NRC's Seventh Edition of the NUTRIENT REQUIREMENTS OF DAIRY CATTLE Survey Results

Provide your own input

# Updates Expansions/Refinements Additions
1 The current NRC does not adequately address the effects of heat stress (Cows and calves) other than through changes in DMI. This is an important area that should be addressed in the models. There has been a good deal of work from Arizona since the 7th edition was published that expands the data available for refinements.
2 Chapter 12
Variability and feeding to group requirements
Component price implications on feeding strategies
3 1.Manure production with different diets, feedstuffs, ages, production systems.
2.Feed management for manure nutrient reduction.
3.Feeding for greenhouse gas reduction.
4.Feeding for manure pathogen reduction.
4 -energy metabolism of lactating cows
-protein metabolism of lactating cows
probiotic effect of lactic acid bacteria on rumen metabolism and immune system of lactating cows.
5 Amino acid sud-model:equations leading to the prediction of absorbed AA (Metabolizable AA)and ideal AA/MP ratios. Specific analysis(feed, ruminal, post-ruminal) needed for the model to predict absorbed nutrients.
6 Agree with revisiting heifer growth requirements, but also suggest revisiting maintenance requirements under different environmental conditions, including for the pre-weaned calf Need to expand the information on feeding sugars under the carbohydrate section 1) Under Environmental Impact, Nitrogen: Discuss implications of milk urea nitrogen (physiological and regulatory)
2) Under "Agents Potentially Toxic to Dairy Cattle" include mycotoxins, endophyte, gossypol, prussic acid, botulism, listeria, and references on poisonous plants.
7 Chapter 4 requirements on fiber and NFC needs major revision. .A requirement for physically effective NDF (Particle size of NDF is probably a better measure than forage NDF in DM)

.An update and consideration of the effective fiber concept (NRC assumes that the concept exists in text, but do not supply guidelines for formulation)

.Rumen degradable starch would be useful (already being considered, I assume)

.Eliminate the NRC 2001 mistake of a maximum NFC requirement (minimum NDF defines maximum NFC)

. Eliminate the ADF requirement
8 You have placed "Metabolizable protein requirements" under "Additions', although it should be under "Expansions/Refinements".

MP requirements should be updated to reflect underprediction of milk and milk protein yields with diets supplying MP below current NRC (2001) requirements.
9 Hi, I am happy to see this but wonder who is behind it. We should be coordinating all the efforts related to this. I am on the NRSP-9 committee that is concerned about NRCs and was recently asked to give a talk on Wed at Indy about needs for the new NRC Dairy. Please give Mark Hanigan or me a call. Mark is in Italy for vacation so you can call me at 517-230-7460
10 Expand the methane reduction approch beyond the feed additives effect as implied. Include feed efficiency, reducing the size of the replacement heifers, selection and other non-conventional potential feed additives etc.
11 The effect of heat stress on dry matter intake and updating the model predictions for DMI during heat stress. Update the diet humidity content on DMI.
Better designing NRC software to fit all the windows operating systems (Vista, 7, 8 as well as other versions).
Effect of different non-forage fiber sources on the passage rate predictions and amino acid flow to the small intestine. Effect of particle size (not forage:concentrate ratio) on passage rate and diet energy predictions. Adding a chapter entitled "practical recommendations for the dairy farmers" to book. I think, this makes NRC book more understandable for non-academic people.
12 review requirements for trace minerals including Mn and Co for all cows, Zn levels for dry cows, iodine levels without and with goitergens in the diet.
13 I would suggest an expansion of, and addition to, the section in chapter 1 on cow behavior, management, and environmental factors affecting feed intake.
14
15 An up-date on the AA requirements of dairy cows is required in my opinion. Specifically, NRC should look at the AA requirement where forages other than corn silage are being fed. In Chapter 12 I think there should be an emphasis on whole farm modelling of N and P efficiency. Indeed, there is probably a requirement at this stage to discuss the effects of one environmental strategy on other environmental losses. For example, if N is reduced on a whole farm level then what impact is this having on LCA emissions or P losses? It may also be worth while to discuss the effects of these strategies on dairy cow health (for example the effects of low P diets). I think this would be a worth while expansion to this chapter. The addition of a feed additive section I think is a worth while exercise. There are many additives that are used commercially, stating various claims on both production and health. A review of this area into a chapter would be nice.
16 - Fiber digestibility and fiber effectiveness of tropical feeds(forages and nonforage sources) - Accounting for silage fermentation end products (organic acids, alcohols) as part of silage dry matter, especially their energy contribution for dairy rations. It will need some focus on methods to determine dry matter content of silages. - Emissions of volatile organic compounds from silages. It could be included within "environmental impact" issues.
17 The energy system needs several refinements, including digestibility discount, digestibility of fat, DE value of protein and how to handle protein not captured, conversion of DE to ME, and conversion of ME to NE.
18 Nutritional requirements of dairy cows under heat stress and feed additives recommended in this period.
19 young dairy calf nutrion from weaning til 6 month of age, to achieve best groth and profitabillity.
20 Dry matter intake
Metabolizable Protein requirements
Heifers growth
Calves growth
Scientific data on low/medium energy close up diets
Fiber requirements
By products nutrient utilization
Additives
Choline
Aminoacids
Pasture/grazing data
21 Update knowledge on carbohydrates included in NFC: composition, ruminal fermentation, nutritional impact. Impact of protein on ruminal carbohydrate fermentation.
Relationship of in vitro estimates of degradation (starch, fiber) with in vivo measures of same.
Low protein diets: including ability to predict animal performance.
Feed analyses: description of those required for the NRC inputs (acceptable options), and information on analytical variability of these assays (defines the precision with which they are determined and guides the precision related to their use).
Sensitivity analyses of any models included in the NRC so users understand what affects them most.
22 I believe that a new section on antioxidant management/supplementation of dairy cows during different physiological status (pregnancy, lactation, dry period) would be of extreme interest for the reader.
23 Macro nutrients (protein metabolism, vitamins and minerlas, fats and fatty acids Incorpration fo the CPM fatty acid sub model
refine mineral bioavailability
24 In the last few years I have calculated the EB of dairy cows in several experiments and realized that the actual LBW gain (or loss) does not fit with the NRC model (2001; chapter 2, pg 22-25). The actual LBW gain was lower than predicted, and the gap between predicted and actual LBW was sometimes too big. I would suggest re-evaluating the NRC model for gain and loss of BW, and especially for high producing dairy cows consuming 25-29 kg of DM. This high consumption strongly influences the gut fill, which I do think mask the real gain in body mass and leads to the discrepancy between the NRC model and real measurements.
25 - Include drinking water as a normal dietary ingredient and the possibility to change the mineral contents in the drinking water to balance minerals in the diet.
- Give the possibility to change or adjust mineral contents in the milk.
- Include free choice salts as an ingredient.
- Expand byproducts data base.
- Maximize the connection between animal nutrition and soil nutrition, including in the outputs an estimation of mineral excretion (all the minerals) in feces and urine for manure management, manure application, or for mass balances at farm level. - Based on the recent research results of tannins in the ruminants diet increasing the efficiency of body weight gain, nitrogen utilization efficiency, and the impact on ammonia volatilization in manure, tannins should be included as feed additive
- Environmental impacts: ten minerals in the manure have been described as possible pollutants that may affect crop production, soil, and underground water. Recommendations of manure management and manure applications should be included based on dietary mineral contents.
26 Minerals/vitamins
Protein
amino acids
specific carbohydrates (e.g., starch)
formulating for groups of cows, not a specific cow. How does group composition (variation in milk yields, DIM, etc) affect formulation goals/ requirements
27 Kemin Industries suggests an update to the amino acid requirements as it relates to rumen protected amino acid (RPAA) supplementation in the 8th edition of Nutrient Requirements of Dairy Cattle. Since the last NRC issued in 2001, the availability and quality of RPAA has improved significantly to the point where diets can be formulated to specific metabolizable protein (MP) levels which improve productivity and efficiency. Enhanced RPAA stems from new advances in technology and a greater understanding by the industry regarding the functional biology of the animal. When the previous NRC established the optimum amount of MP lysine, there was no RP-lysine commercially available in the market. Given the new technology in the market and the improved genetic potential of today’s dairy cattle requiring higher levels of nutrients than pre-2001, requirements for all essential amino acids need to be updated. Kemin Industries suggests the review of the macro-and-micro-mineral availability model, as well as updates to the vitamin and trace mineral requirements specifically in regard to chromium (Cr), in the 8th edition of Nutrient Requirements of Dairy Cattle. In the last NRC, there was no recommendation on supplementation of chromium as quoted, "...the amount of chromium required for optimal performance is unclear and the literature does not support a general recommendation ..." Since 2001, there have been at least 18 refereed scientific journal publications on the effects of Cr supplementation in dairy cattle. Chromium supplementation has consistently improved performance in lactating dairy cattle – up to 5.4 kg of daily milk yield per head per day along with enhanced health and immune function characteristics. We believe this research is sufficient to warrant the review and development of a feeding recommendation for Cr supplementation of dairy cattle diets. Additionally in 2009, the United States Food and Drug Administration Center for Veterinary Medicine Division of Animal Feeds permitted the supplementation of Cr from chromium propionate in cattle diets, which makes it imperative to develop a clear NRC recommendation for Cr supplementation. Kemin Industries suggests regulatory aspects of nutrition be considered for the 8th edition of Nutrient Requirements of Dairy Cattle. The United States dairy industry is coming under increasing regulatory control from various agencies; therefore, dairy nutritionist and feed formulation personnel need to have a greater understanding of these regulatory aspects moving forward.
28 Choline has been shown to be a required nutrient for companion, laboratory and non-ruminant production animals and fish. Choline functions as component of cell membranes, lipoproteins that transport lipids through the circulatory system, and the neurotransmitter acetylcholine. Choline serves as a source of methyl groups and may interact with other nutrients involved in one-carbon metabolism. Previous NRC committees have not included choline as a required nutrient for adult ruminants because of the lack of research to establish a recommendation. For example, the dairy NRC (2001) states: “The establishment of a choline requirement, either for the lactating dairy cow, or a transition cow in the late dry period and in early lactation, will require more extensive feeding experiments than available at the time of this publication.” There is now sufficient evidence that choline should be included in the next NRC as a required nutrient for transition dairy cows, i.e., cows from 3 wk prepartum to 3 wk postpartum. Choline should be listed as a required nutrient because 1) transition dairy cows exhibit the classic choline deficiency symptom and 2) the deficiency symptoms can be alleviated by supplementation of choline that is protected from ruminal degradation. Research since the 2001 NRC shows: forty to sixty percent of transition dairy cows exhibit moderate to severe fatty liver (Bobe et al., 2004, J. Dairy Sci. 87:3105). Liver tissue has a high requirement for choline because daily hepatic fatty acid uptake increases during the transition period by more than 10-fold (Reynolds et al., 2003, J. Dairy Sci. 86:1201). Hepatic fatty acid oxidation does not increase proportionately, therefore, choline, as a constituent of phosphatidylcholine, is needed for exporting fat from the liver as part of very low density lipoproteins (VLDL; Cole et al., 2011, Biochim, Biophys. Acta 1821:754). Greater than 95% of free dietary choline is rapidly degraded in the rumen (Sharma and Erdman, 1988, J. Dairy Sci. 71:2670). This along with the high requirement for choline contributes to the large proportion of transition cows exhibiting the classic deficiency symptom. Feeding choline protected from ruminal degradation reduces fat accumulation in the liver during the transition period and negative energy balance (Cooke et al., 2007, J. Dairy Sci. 90:2413; Zom et al., 2011, 94:4016). Expression of genes involved with VLDL assembly and secretion are increased in transition cows supplemented with protected choline (Goselink et al., 2013, J. Dairy Sci. 96:1102). Results from thirteen studies in which protected choline was fed to transition dairy cows indicates supplementation increases milk and energy corrected milk yield 2.2 kg/day or more (Pinotti et al., 2010, Energy and Protein Metabolism and Nutrition, EAAP Publ. 127; Grummer, 2013, Page 27 in Proceedings of the Florida Ruminant Nutrition Conf.). Feeding rumen-protected choline to transition cows improves animal health including a reduction in ketosis, subclinical ketosis and mastitis (Lima et al., 2012, Vet. J. 193:140). As in other animals, methionine may be able to contribute methyl groups for hepatic synthesis of phosphatidylcholine. However, research to date suggests that supplementation of rumen-protected methionine or methionine analogs does not reduce fat accumulation in the liver and, therefore, cannot fulfill the role of protected choline in diets fed to transition dairy cows (Socha, 1994, Ph.D. Thesis; Bertics et al., 1999, J. Dairy Sci. 82:2731; Piepenbrink et al., 2004, J. Dairy Sci. 87:1071; Preynat et al., 2010, J. Dairy Sci. 93:2130).
29 Dear Sir

I think It will be very good if you add a chapter about the inflammation in dairy cattle. There is link between inflammation and metabolic disease and it could change the nutrient requirement of dairy cattle.

Regards

Golnaz
30 Update the accuracy of estimating DE,TDN and subsequently NEL of forages with the NRC prediction equation. The major commercial testing labs used the NRC equations and have a large data set of forage analyses that could be used for this purpose. Estimating or predicting the digestible fiber component of the prediction equation is of particular interest. Comparisons of forage DE prediction based on in vitro digestible NDF predicted digestible NDF based on lignin as components in the TDN equation should be compared. Dry matter intake prediction is currently based on caloric requirements (maintenance +production) and days in milk. Dry matter intake prediction could be refined further to account for dietary factors such as caloric density and/or effective neutral detergent fiber.

The equations for predicting nutrient requirements and feed nutrient specifications should conform to Excel spreadsheet ration formulation programming. Metabolizable protein needs more refinement in this area.
Develop nutrition guidelines for pasture based dairy production. There is an increase in interest in these dairies (aka grazing dairies) that have less cost associated with infrastructure, labor, health, reproduction, health and waste. Recommendations for maximizing forage nutrient intake with intensive rotational grazing of irrigated pastures as well as the need for supplemental feeding is needed.
31 I believe an important addition to the new NRC dairy cattle model will be the inclusion of a fatty acids submodel that estimates duodenal flow, intestinal absorption and indicates requirements at least for linoleic and linolenic acids. There are substantial data supporting the effects of linoleic and linolenic acids, as well as EPA and DHA on production, milk composition, immune response, and some data on fertility.

I and colleagues at the University of Florida would encourage the committee to think about this and include data relative to fatty acids beyond what other fat submodels (CPM) have used.



It would be a major improvement for the NRC to provide some guidelines on feeding these fatty acids. Studies have been published to evaluate the effects of essential fatty acids for young calves, as well as for late gestation and early lactation cows.
32 My second suggestion for the new NRC dairy cattle model is to include choline as a required nutrient for late gestation and early lactation dairy cows.

I believe there are sufficient data in the literature to support the benefits of feeding choline to reduce hepatic triglyceride accumulation, reduce the risk of ketosis, and improve yields of milk and milk fat.

We have considered choline as feed additive to cattle, when it is a required nutrient for other species. It think the NRC committee will be able to find sufficient evidence in the literature to support the recommendation of including choline as a required nutrient for dairy cattle.
33 The fatty acid profiles of feeds should be included in the description of feedstuffs when possible. Much is already in the CPM submodel. Recent lactation, growth, reproduction, and health/immunity data using cows and calves indicate that specific dietary fatty acids have physiological roles of which we are now learning. While we may not know requirements, it is possible that recommendations can be made which is also the role of the NRC.
34 Particle passage rate information
Relationship between intake and digestibility (emphasis on forage)
Splanchnic metabolism of VFA Effect of dry matter intake and diet composition on methane emissions
Expand feed analysis for precision feeding
Definition of feed efficiency
35 Include evaluation of efficiency of nitrogen use;
Include NDFfe requirements;
36 Classical energy based systems have at their core empirically derived estimates of animal requirements. These yield efficiencies of ME utilization that are inconsistent with efficiencies calculated from known biochemical pathways. Application of more modern statistical tools (Markov Chain Monte Carlo estimation of parameter variability) to ordinary least squares equations return results indicating model misspecification.

In these classical systems MEm or FHP are considered to be fixed points and even when, in some systems, there is an allowance for an increase in either, those are not different statistically from either value (MEm, FHP) as described by Lofgreen and Garrett (1968). Maintenance is a function of the fed state and should be characterized as such in both growing animals and lactating cows. It does not appear to be a linear function of metabolic body size. For the growing animal characterizing dRE/dMEI as a function of RE fits the data better than the classical approach taken by Lofgreen and Garrett(1968) and returns estimates of efficiencies of ME utilization for maintenance and gain consistent with known biochemical pathways. Further, MCMC evaluation of parameter estimates indicates parameter stability for a first order equation.
Cattle and the microflora in their gut utilize chemical, not proximate entities. While the detergent fiber residue procedure is archaic the objection to the process should be the variable nature of the residue. Feeds should be characterized as to their chemical, rather than proximate composition.

Ruminal degradation of feed components can be described as the first derivative of dx/dt = f(x) with lag times and undegraded fractions (or similar equations) estimated using nls methods. The simplistic approach of "curve peeling" yields equations that are unrealistic.
As regards residual feed intake; I have not examined RFI in lactating dairy cattle but have found that the most commonly used equation (in growing cattle, DMI= a + b1MBS + b2ADG) returns parameter estimates inconsistent with animal biology. For an intercept different from zero, if positive then cattle with no mass nor gain consume feed and if negative then feed is produced. Coefficient b1, when multiplied by ME (Mcal/kg feed) is purported to be MEm, but ranges from 0.150 to 0.300. The first derivative of the equation with respect to ADG is a constant, indicating that energy content of gain is unchanged over a range of rates of gain. This is not supported by any NRC "Nutrient Requirements of Beef Cattle" in which the first derivative is b2ADG. Estimates of the partial efficiency of ME use for gain are either biologically unrealistic or violate the first law of thermodynamics.

Estimates of production, based on inputs, should have confidence intervals about those estimates and vice-versa.
37 Lactation:
Update knowledge on heat stress cow and transition cow feeding
Individual fatty acid requirements,especially for C16:0,C18:1,C18:2 and C18:3

Metabolizable glucose requirements
38 The section on vitamins should be updated since there is new literature available.
More is known about the environmental effect of using organically bound trace elements. This should be updated.
With cows being held on TMR feed and supplemented with fats of various qualities, one should include a section on the requirement of unsaturated fatty acids. A section on mycotoxin binders would be recommended since contamination with mycotoxins is unavoidable under certain climatic conditions. NRC should provide guidance to the legislators regarding the precise conditions of the use of such binders.
39 The NRC needs to address group feeding of cows versus feeding an individual with equations for intake and what lead factors should be used to balance rations for feeding dairy cows.
40 Expand the Energy value of feed beyond MCal of energy and refine their nutrient value on their impact on the metabolism. This is needed particularly with fats (specific fatty acids) and carbohydrates (glucose and other sugars).
41 NEW THI index with stress threshold for high producing cattle (>35 kg/day). We can provide expansions/refinements on relationship between THI and water intake, feed intake, posture (lying or standing) and milk yield and composition
42 Refinements on Lys:Met ratio, because there is growing evidence that shows this ratio does not have a huge effect on production. Also, new data suggests that the Lys effect on milk protein yeild is not as big as we thought before.
43 dry matter intake prediction equation a more extensive validation of the accuracy of the current TDN calculation and adjustment for effect of intake using in vivo total tract digestibility data from lactating cows published since 2001

expansion/improvement in modeling the effect of increasing dry matter intake on rumen dynamics, metabolizable protein supply

review of metabolizable protein demands in early lactation, labile protein reserves and effects on peak production and persistency
better description of total sulfur amino acid requirements and methyl group metabolism in dairy cows
44 -expand the knowledge on fatty acid metabolism within the rumen, including the long chain PUFAs such as DHA and EPA -develop a model on fatty acid metabolism within the rumen and post-absorptively, including long chain PUFAs such as DHA and EPA -expand the knowledge on nutrient requirements during disease states
45 In chapter 1, there is much newer research to add to and refine the section on cow behavior, management, and environmental factors affecting feed intake.
46 A dietary glucogenic precursor requirement i.e. bypass starch, bypass glucogenic amino acids, propionate salt or ionophores to mediate insulin resistance to enhance oxidative metabolism, reduce ketone synthesis and overall improve energetic efficiency.
47 The NRC committee should be able to determine the requirment for fatty acids in general and specifically for CLA isomers like the t10, c12. It comes in pare pasture milk in very small but effective amounts in spring and early summer. Literature meta analysis (DeVeth et al., 2009)has shown a significant positive effect on reproduction if supplemented in to TMR diets.
48 The MP allowable milk predictions over predict the marginal response to MP (slope bias) because the efficiency of conversion of MP to milk protein is 45% rather than 65% as assumed in the model.

The NEL allowable milk still appears to be overpredicted (mean bias) by about 3 kg which is better than the 8 kg error in the 89 model, but still not 0 as it should be.
A riminally available CHO system is needed to allow better predictions of acidosis and rumen function including methane production.

P availability in feed can be better represented based on Knowlton's work on P digestion.

The effects of unsaturated and trans fatty acids on milk fat depression need to be considered.

Update the amino acid equations.
Predictors of environmentally sensitive outputs.
49 Include a weight loss prediction in the calf model when low levels of nutrition and/or cold temperatures cause such. Also, attempt to include impact of heat stress.
50 Cover diet induced changes and pathology of digestive tract. Displaced abomasum, Sub acute ruminal acidosis and lameness, bloat, parakeratosis of rumen wall, liver abscesses abomasal ulcers, hemorrhagic bowel syndrome
51 14 Nutrient Requirement Tables.
1.) Update tables of byproduct/co product feeds like DDGS, adding High Protein (HP) DDGS. FeedAC database currently being held by David Mertens has data from 2001 to 2011 that should be utilized.
2.) Extensive database information on forages is available from commercial labs. NY Dairy One Lab; Mid- Ch west Labs; and others have told me they will help if asked, if given credit.
3.) Add Algae and Kelp feeds with analysis recently published in JDS. Other analysis may be obtained from papers published in J. of Animal and J. Poultry Sci.
Ch. 10 Nutrient Req. of the Young Calf.
Add feed additives for pre ruminant calves. Mono oligio saccharides (MOS) and Beta-glucans have been shown to improve hip height, ADG, and reduce fecal score.
Add requirements for Cr.

Add Fatty acid data to Feed Tables Ch # 14.
52 1 1 1
53 Transition model:
- DMI prediction- how to regulate dry matter intake during transition period (-30 to +60 calving)
- Rumen digestibility equations for each ingredients according to DMI (based on rate of passage) then total tract digestibilities.
- The efficiency of small intestine digestibilities by the amounts of escaped nutrients from rumen fermentation.
Calf growth model and Dry matter intake prediction Calf disease control with antibiotic-free diet: best solution for avoiding from pathogen.
Evaluate organic minerals
54 first, let me thank you for making this happen, I think this is a great way forward. I will use this section for some of the bigger issues (processes) instead of details. the bigger issues are more important:
1) who uses the Dairy NRC? and in what ways:
a) legal document for dairy requirements
b) actual on farm or in commercial use as a ration balancer or evaluator (computer program or model)
c) scientists and nutritionists in research
d) faculty and students in education/teaching

The answer is of course, all of the above but in different ways. probably b) is the least use BUT the Dairy NRC provides the scientific, justifiable background and basis for updating and evalauting on farm models and research studies.
2) who pays for it
a) to produce
in the past, the feed industry, and perhaps some from NAS and some from FDA paid for the upfront costs.
University faculty donated time to produce it
user fees recouped some of the funds-books were purchased by companies, nutritionists, libraries, faculty students. This must be kept in mind. Pricing the actual product is critical--too high and students and faculty wont' buy it.
New Paradigm:
Industry pays up front, more, and the product costs the same.
FDA, which uses the book as their base, pays more up front.
ARC/NIFA pays the faculty who write it (at the very least with release time or a direct written acknowledgement that this activity counts toward their research productivity but BETTER they actuall get paid release time (overload) and/or paid support (postdoc/student) to help with their programs (committee members can choose) b) for use
the actual book needs to be priced so that faculty and students, the largest population of people that use it, can afford it. It is the faculty and students who evaluate it , learn it and sell it forward. Industry companies and nutritionists pay the same price and use as they see fit.
3) who writes it? and what makes it worth their while
-see comments above on who pays for it
4) what is the new update paradigm?
the NANP must be explicitly involved (committee members/advisors/coordinators) so that the product is made for regular updates (annually, biannually) with new feed data base information or new requirements as they are discovered and validated.

AND I (JOHN MCNAMARA) WOULD LIKE TO BE INVOLVED ON THE NUTRITION AND REPRODUCTION PART AS WELL AS IN SCIENTIFIC AND PRACTICAL INFORMATION ON VARIATION IN NON MAMMARY GENETIC DIFFERENCES ON REQUIREMENTS (MODERN MODELING).
in addition to all the excellent suggestions, we MUST have:

nutritional support of or effects on reproductive fertility
glucose
energy balance
fatty acids
amino acids/N/ammonia
milk production/metabolic rate on steroid degradation.

Effects of genetic improvement and variation on requirements (this can be as simple as milk output, milk fat and milk protein output)AND effects of non-mammary genetic variation (liver/muscle/adipose) on requirements. the cow is not just an udder and a mammary gland and everyone knows this now and we have data on VARIATION in requirements and should codify it.

no one size fits all linear constants relating milk components etc to energy or amino acid or fatty acid requirements. the stage of lactation, level of milk and component production and genetic variation in tissue metabolism alter this.

better data on feed mixing and physical form of diet effects on intake.
see expansions and refinements

thanks for doing this.
55 A personal view: NRC should limit itself to quantifying nutrient supply, nutrient requirement and (the other side of the coin), response to nutrients. 'Requirements and responses' should cover those outputs of the system of importance to society, the farmer and the animal: milk yield and composition, body state change, health and well-being, reproduction and environmental impact.
The emphasis must be on QUANTIFICATION: updating a system for ration formulation and evaluation. The update should NOT include deep qualitative reviews of a diverse range of topics related to dairy nutrition and management: in today's information-rich age there are other, better formats for this and NRC should be wary about taking on too much. Resist the temptation and be realistic! Stick to those topics of nutrient supply and requirement that can be (reasonably) quantified! One measure of success will be the size of the final document: it should be shorter than NRC (2001).
On nutrient supply, the focus should be on models, not the creation of a primary database. NRC should liaise with other international activities (specifically Feedbase.com) to prevent duplication of effort.
56 A critical revision of our standpoint on dairy cow nutrition during the dry and transition period is required. Adequate nutrition during these periods is of vital importance to our sector.
Inadequate feeding strategies not only result in higher risks of metabolic disorders, but new insight also taught us that these metabolic disorders are associated with changes in the immune status of dairy cows and consequently also to their response on infectious agents. For instance, supporting fat metabolism by supplementing rumen protected choline not only resulted in less hepatic lipidosis, but also in a lower incidence of mastitis. The link between feeding strategies during the dry en transition period, metabolic disorders (fatty liver, ketosis) and infectious diseases should be emphasized.
For a better understanding of dairy cow metabolism in the transition period, a change in our mind-set is vital. Too often nutritionist and veterinarians spread the theory that fat mobilization in early lactation is caused by a too low energy intake. It has been more than 10 years that Friggens hypothesized that fat mobilization is a normal physiological phenomenon in all mammals. It should be realized that milk energy output at the start of lactation is higher than feed energy input because the animal adds extra energy (from its body reserves) as a consequence of this physiologically normal process. So, the emphasis in feeding strategies should shift from measures to increase DMI / energy intake at any cost towards measures to prevent massive fat mobilization and to support fat metabolism. A change in mind-set will open new ideas on how to deal with this apparent “negative energy balance”.
Healthy cattle, reduced involuntary culling due to infertility, mastitis and lameness will reduce the required number of replacement heifers. Consequently, preventing metabolic disorders during the transition period will contribute to a high feed efficiency on herd / farm level and to a reduction of the environmental impact (N, methane) of dairy production.
57
58 Energy and protein requirements for feeding dairy bull calves after birth through weaning with the goal of raising them for beef. The current NRC is vague for raising dairy bulls for beef under 350-400 lbs or so. Review of research on medications and treatments of scouring dairy calves including oral rehydration solutions and probiotics.
59 We should address animal welfare issues in order to avoid those severe impacts of media repercussions that pork and poultry has experienced in many countries. Example: The 5 Freedoms of Animals as laid out by the Brambell commission ranks as no.1: Freedom from hunger and thirst... Are we working on the right track here, if the negative energy balance of transition cows keeps growing, running her into ever deeper metabolic trouble which we should name what it is: controlled starvation. We need to pay attention here.
60 a review and critique of existing ration formulation models would be helpful for those who have not witnessed their development over time discuss gut flavor receptors in relation to feed additive actions

discuss colostrum replacers, source and efficacy of supplemented IgGs, and effects of colostrum heat treatment

discuss role of methyl-donor nutrients and applicable analytic assays
61 The inclusion of zinc, copper and manganese hydroxy chloride trace mineral as a newly approved source of trace mineral supplmentation for dairy cattle manufactured by Micronutrients. Hydrox trace minerals (specifically copper hydroxychloride (TBCC) has been recongnized an important source of copper supplementation in poultry ans swine NRC publications). Unlike conventional inorganic trace minerals or better known organic trace minerals which have a high level of solubility at neutral pH, hydroxy trace minerals have very low solubility at neutral pH. This unique feature effectively protects the trace mineral from being degraded in the rumen and subsequent negative reactions with antagonists as the each hydroxy crystal passes through the rumen. This results in an increased level of biologiocally active trace mineral available for absorption in the intestinal tract. Several university studies exist to colaborate the effects highlighted above plus performace based studies designed to demontrate the effect of optimizing the delivery of esssential trace minerals to the blood stream on cow health and productivity. Please advise what additional material are required for evaluation by the committee.
62 I encourage the addition of a vitamin C requirement for the pre-ruminant calf. Below, I list citations that exemplify the need to establish this requirement. If you would like the individual papers, I would gladly send them to you. Thanks for your consideration.

Vitamin C has been shown to reduce ocular and nasal discharge in the young, milk-fed calf(app. 4.5 g/calf/day, Eicher).

Vitamin C has been shown to enhance IgG production in highly stressed calves (Cummins).

In a Czech study, plasma ascorbic acid levels were significantly lower in calves with diarrhea verses those without, indicating vitamin C is used to fight stress (Sahinduran). An earlier Czech study showed calf plasma ascorbic acid levels were lower in comparison to healthy calves both during acute phase and 21 days post a bronchopneumonia respiratory challenge. Calves were between two and three months old (Jagos).

Supplementation of vitamin C has been shown to reduce scours 2.6 fold (Seife) and decrease incidence of naval infections and pneumonia (Nockels). Although the liver of cattle can generate ascorbic acid, it's also been shown that significant levels are not produced until 2-3 weeks age (Lundquist) and other observations note production does not occur until four months age (Wegger).

Canadian research in calves fed only their dam's colostrum and whole milk shows that plasma ascorbic acid levels plummet from birth to 21 days before plateauing out, indicating appreciable synthesis doesn't occur until approximately 21 days age (Hidiroglou, Ivan).

Vitamin C clearly helps maintain calf health and immune function and depletion rates during the first weeks of life demonstrate a requirement. I encourage establishing an NRC requirement of minimum 200 mg/day ascorbic acid for the young, milk-fed pre-ruminant calf.

Citations:

Eicher SD, Morrill JL, Blecha F, Higgins JJ, Anderson NV, Reddy PG. Neutrophil and lymphocyte response to supplementation with vitamin C & E in young calves. J Dairy Sci. 75:1635-1642. 1992.

Cummins CA, Brunner CJ. Effect of housing on plasma ascorbate and endocrine and immune function J. Dairy Sci 74:5. 1991.

Sahinduran S, Albay MK. Supplemental ascorbic acid and prevention of neonatal calf diarrhea ACTA Vet BRINO 73:221-224. 2004

Jagos P, Bouda J, Dvorrak R. Ascorbic acid levels in bronchopneumonia of calves. Vet Med (Praha) 22(2):133-146. 1977.

Seife HA, Mokhber Dezfuly MR, Bolurchi M. The effectiveness of ascorbic acid in the prevention of calf diarrhea. J. Vet Med. B43:189-191.1996.

Nockels CF. Immunoenhancing vitamins for cattle. Agri-Pract. 9:10-13. 1988

Lundquist NH, Phillips PH. Age related studies on ascorbic acid metabolism in animals J. Dairy Sci 25:286-395. 1942.

Wegger. Moustgaard. Age variations in plasma ascorbic acid levels in calves. Page 16 in 25th Anu. Rep. Sterility Res. Inst., R. Vet Agric. Univ., Copenhagen, Denmark.

Hidiroglou M. Ivan M, Batra TR. Concentrations of vitamin C in plasma and milk of dairy cattle. ann. Zootech. 44:399-402. 1995.
63 Content of this input to Committee is from three people suggesting new NRC covers or has a section on feeding cattle on Pasture.

Dear Ken, I visited today with Dr. Darío Colombatto who shared some time with you during your visit to Argentina. I was out of the country so I didn´t have the chance to visit with you.
I am writing this email regarding the new NRC. My friend Alejandro Castilllo from UCDavies told me that you are going to be highly involved.
I am very interested on helping with Committee with a potential chapter for grazing dairy cows. I did my PhD on that area with Dr. Larry Muller and Gaby Varga at PSU.
It is very importance to remember that the NRC is not only the main guide to feed cows in the US, but also out of the US in countries such as New Zealand, Australia, South Africa, Costa Rica, Colombia, Ecuador, Chile, Argentina, and Uruguay where most of the dairy systems use pastures supplemented with concentrates and conserved forages. In fact, those countries must add more than 10 millon dairy cows, similar to the US.
Therefore, I want to offer my help with the new NRC. Please find attached my resume and one review published in the JDS. From Fernando Barga

Hello Ken
I am writing is that I had promised to give you some names about experts on pasture and milk production for the new NRC. The first name I can tell you is Dr Fernando Bargo (fernando.bargo@gmail.com) who is a renowned expert on milk production from pasture based systems. He holds the second longest article in the history of JDS, with his literature review on the topic, published in 2003. I personally think Fernando is a sure bet in order to help you in this task. Other names I can think of are Dr Pablo Chilibroste from Uruguay, Dr Pablo Gregorini from USDA and Dr Ronaldo Vibart from New Zealand (ronaldo.vibart@agresearch.co.nz). Dr Ian Lean from Australia could be another one to call upon. I can find the other emails in case you need them.
Best wishes
Dario Colombatto

Ken
Fernando Bargo (included in this email) contacted me and I suggested him to contact you, about the "grazing" subject for the new NRC. In my opinion, the best way to go with this is trying to contact the right people and make an on-line "Grazing Sub-Committee" to discuss this and make a plan. My question for you is if you think that this can be possible and second, according to you contacts, who can be the possible candidates for this sub-committee? We know with Fernando some possible names from Australia and New Zealand, but for USA your opinion is very important.
All the best.
Alejandro Castillio
University of California Cooperative Extension
Merced, CA.














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64 Chapter on pasture/grazing dairy systems with supplementation and TMR supplementation
65 I would recommend re-evaluating the body gain and loss prediction model in high yielding dairy cows. In my previous few experiments with daily individual measurements, I realized that the NRC (2001)model is over estimated and the actual BW gain was much lower than predicted.
66
67 NRC should move away from describing body weight change simply in kgs. Animals lose/gain fat and protein reserves, and also alter gut fill. The balance between these three types of 'weight' has big implications for nutrient requirements. Body condition score is a good indicator of success in diet formulation and feed supply - fat cows are overfed and thin cows are underfed. There are many studies to show that cows over-conditioned at calving will have reduced appetite and more severe negative energy balance. NRC should include maintenance of appropriate BCS as a goal in meeting nutrient requirements.
68 Those are some amazing stats ineedd, awesome job FS and Psyfireman for all the work you poured into this as well as the thousands of players who keep coming back for more. Those are some amazing stats ineedd, awesome job FS and Psyfireman for all the work you poured into this as well as the thousands of players who keep coming back for more. Those are some amazing stats ineedd, awesome job FS and Psyfireman for all the work you poured into this as well as the thousands of players who keep coming back for more.
69 Ajinomoto Heartland, Inc. suggests that the updated NRC should refer to methodologies for determination of bio-availability of rumen protected amino acid (RPAA) products.

Several rumen protected lysine products (RP-Lys) have been commercialized for last several years, and it is becoming more and more common to formulate the dairy diets on metabolizable Lys basis with using RP-Lys in the formulation matrix. As far as the bio-availability of RP-Lys products is concerned, however, there is no standardized methodology, and as a consequence each RP-Lys manufacturer suggests the bio-availability of its product based on its own evaluation which is sometimes lacking in objective validity.
For example, the in situ Dacron bag technique has been traditionally used to determine the degree of protection of RPAA. But the value obtained with this technique does not take into consideration the proportion of physically broken RPAA particles by rumination and chewing, thus potentially has a risk of overestimating the ruminal escape of the products.
Another example is related to the digestibility of RPAA products. Most RPAA products are using solid fat as a protective substance, and the digestibility of the products is defined just based on the digestibility of fat. According to NRC 2001, however, the digestibility of various fat sources varies a lot depending on the origin, composition of fatty acids, and the degree of saturation. For instance, solid fat (or highly saturated fat) is generally less digestible than liquid fat or fat partially hydrolyzed. If the manufacturers of RPAA don’t refer to this difference in digestibility by fat sources, it is highly likely that the digestibility of RPAA products is way too overestimated.
Less accuracy in bio-availability suggested by RP-Lys manufacturers results in less precision in diet formulation, which is a loss for the industry. Therefore, it is desired to have a standardized methodology to precisely evaluate the bio-availability of various RPAA products.

Plasma free Lys concentration has been considered as a quantitative marker of the absorbed amount of Lysine in dairy cows. Whitehouse et al. published a poster in which they examined the dose-response relationships between plasma free Lys concentrations and intestinally or abomasally infused Lys in lactating dairy cows (J. Dairy Sci. Vol. 95, Suppl. 2, p 345, 2012), and confirmed that the plasma free Lys response approach can be utilized for determining Lys bioavailability of RP-Lys supplements. In the next step, Whitehouse et al. tried to quantify the bio-availability of a commercialized RP-Lys product using the plasma free Lys technique (J. Dairy Sci. Vol. 95, Suppl. 2, p 115, 2012). The results suggest that the bio-availability value of RP-Lys products can be precisely measured with the plasma free Lys response method.
Based on those studies, Ajinomoto Heartland, Inc. suggests that the updated NRC should recognize that the plasma free Lys method documented by Whitehouse et al. is a reliable and useful methodology to determine the bio-availability of various RP-Lys products. This method should be considered as a standardized technique for evaluation of bio-availability of the RP-Lys products.
70 Because my suggestion did not appear in the list of previously received external input, I am re-sending my input as below.

Ajinomoto Heartland, Inc. suggests that the updated NRC should refer to methodologies for determination of bio-availability of rumen protected amino acid (RPAA) products. Several rumen protected lysine products (RP-Lys) have been commercialized for last several years, and it is becoming more and more common to formulate the dairy diets on metabolizable Lys basis with using RP-Lys in the formulation matrix. As far as the bio-availability of RP-Lys products is concerned, however, there is no standardized methodology, and as a consequence each RP-Lys manufacturer suggests the bio-availability of its product based on its own evaluation which is sometimes lacking in objective validity.
For example, the in situ Dacron bag technique has been traditionally used to determine the degree of protection of RPAA. But the value obtained with this technique does not take into consideration the proportion of physically broken RPAA particles by rumination and chewing, thus potentially has a risk of overestimating the ruminal escape of the products.
Another example is related to the digestibility of RPAA products. Most RPAA products are using solid fat as a protective substance, and the digestibility of the products is defined just based on the digestibility of fat. According to NRC 2001, however, the digestibility of various fat sources varies a lot depending on the origin, composition of fatty acids, and the degree of saturation. For instance, solid fat (or highly saturated fat) is generally less digestible than liquid fat or fat partially hydrolyzed. If the manufacturers of RPAA don’t refer to this difference in digestibility by fat sources, it is highly likely that the digestibility of RPAA products is way too overestimated.
Less accuracy in bio-availability suggested by RP-Lys manufacturers results in less precision in diet formulation, which is a loss for the industry. Therefore, it is desired to have a standardized methodology to precisely evaluate the bio-availability of various RPAA products.
Plasma free Lys concentration has been considered as a quantitative marker of the absorbed amount of Lysine in dairy cows. Whitehouse et al. published a poster in which they examined the dose-response relationships between plasma free Lys concentrations and intestinally or abomasally infused Lys in lactating dairy cows (J. Dairy Sci. Vol. 95, Suppl. 2, p 345, 2012), and confirmed that the plasma free Lys response approach can be utilized for determining Lys bioavailability of RP-Lys supplements. In the next step, Whitehouse et al. tried to quantify the bio-availability of a commercialized RP-Lys product using the plasma free Lys technique (J. Dairy Sci. Vol. 95, Suppl. 2, p 115, 2012). The results suggest that the bio-availability value of RP-Lys products can be precisely measured with the plasma free Lys response method.
Based on those studies, Ajinomoto Heartland, Inc. suggests that the plasma free Lys method documented by Whitehouse et al. is a reliable and useful methodology to determine the bio-availability of various RP-Lys products. This method should be considered as a standardized technique for evaluation of bio-availability of the RP-Lys products.
71 When we discuss the environmental impact of dairy, many people talk about methane and how to mitigate its emission through dairy production. It is good that the updated NRC is going to add a section of Environmental Impact and refer to methane reduction. However, the NRC should pay the similar attention to Nitrous Oxide (N2O) as N2O is about 300 times more potent GHG than CO2 while methane is 21-fold potent than CO2. Although the total emission (ton) of N2O is much less than CO2 or methane, its impact on global warming is not negligible due to its high potency as a GHG.
In swine and poultry nutrition, it has been well documented that feeding a diet which is low in crude protein and appropriately balanced on amino acid by using synthetic amino acids such as L-Lys, L-Thr, L-Trp and DL-Met can significantly reduce the excretion of nitrogen into manure and hence can reduce the emission of N2O generated during the manure treatment process without compromising the growth performance of animals. Some researchers have estimated the carbon footprint (CFP) of pork based on Life Cycle Assessment, and have revealed that feeding an amino acid-balanced and reduced CP diet is an effective practice to reduce the CFP of pork. On top, pigs fed a low CP diet consume less water than those fed a high CP diet and the total volume of manure is reduced when the low CP diet is fed. Thus, it results in saving water in pig production and saving the cost for manure treatment.
The similar effects are expected in dairy as well, because some researchers already reported that lowering dietary CP content could result in lower excretion of nitrogen in manure of dairy cows. Since the mechanisms of N2O emission from the manure treatment process is not different between pig and dairy production, it is very rational to say that feeding an amino acid balanced and reduced CP diet to dairy cows must be an effective practice to reduce the environmental impact without negatively affecting the production performance. And, the recent increase in the availability of rumen protected amino acid products is definitely of great help to implement this practice in an economically feasible manner.
Because “Sustainability” has been drawing more and more attention in many industries and the dairy is not an exception, the updated NRC should refer to the nutritional practices that can contribute to the sustainable growth of the dairy industry. Then, because of the reasons above, I suggest an addition of a description regarding “reduction of N2O emission through dietary manipulation” in the section of Environmental Impact.
72 It is assumed that the committee will be looking at the many dynamic sub models that have been developed outside of the USA as well as within the USA.

there is a need in the post wean calf model to provide more accurate estimates of rates of passage than is currently being used.

We need a more robust rumen sub model with fermentation predictions as well as coupling this with VFA metabolism. It is assumed that the work done by Russell as well as his colleagues at the forage lab will be used.

It is suggested that the amino acid sub model need to include all amino acids - essential and non essential. The non essential AA play important roles in energy metabolism as well as other metabolic areas. comments have been made both on improved ideal protein approach as well as improving the factorial approach. It is strongly suggested that much emphasis needs to be placed on the dynamic aspects of metabolism as suggested by Lapierre as well as incorporating the concepts of active uptake sites for amino acids per the work that has been done by Baumrucker, Penn State.

It is suggested that a rumen sub model be developed in the mineral area. The current model focuses mostly on the digestion and factorial requirements with discussion of antagonists but little if any recognition of the microbial dynamics

It is agreed with the other comments on the development of a FA sub model. Emphasis needs to really be placed on FA metabolism in the model.

Agree with all of the comments on the CHO areas. We do need to be more definitive on the areas of fermentation products from silages as well as the soluble fiber area such as pectin's and Beta glucans.

would suggest including in the DMI intake model the concept of gut fill relative to the slow and indigestible fiber pools as well as a more mechanistic model rather than the current empirical ones

It is assumed that a more mechanistic passage model will be developed based on particle size, particle size reduction rate and specific gravity coupled of course with rates of digestion of the various pools

With the starch sub model as well as the other sub models - time to recognize that there is a hindgut. there are enough data available to develop this model

good luck in doing this. Was worried it would not happen. Please put emphasis on the model development and not waste precious time on development of platforms.

73 Updates of benefits of controlled energy rations in the dry period
Update metabolizable protein and amino acid requirements for pre-fresh and fresh cows
Update rumen pH estimates based on peNDF and expanded discussion on buffering needs of diets
Update dietary factors that impact milk component yields including the impact of saturated fats and K on milk fat and amino acids on milk protein.
Accelerated growth programs in calves.
Non-structural carbohydrate fractions of feedstuffs and ruminal fermentability of these carbohydrate fractions.
Feed database to include ethanol distillers grains and more byproducts.
Impact of early life nutrition on lactation performance
Nutrition through automatic calf feeders and the impact of feeding frequency on intake and growth of dairy calves.
Evaluate variable efficiency of MP use with balanced amino acid supply
Effect of feeding behavior on DMI
Hepatic oxidation theory and its effect on intake
Impact of different fatty acids on reproduction.
Various levels of carbohyrate fractions during the transitio period.