The Modern Dairy Cow

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2 The Modern Dairy Cow A marvel of a biological system to convert a wide range of feeds into high quality protein products for consumption by humans. What are the limits in terms of milk production? Recent world record milk production: - 4 year old cow, 365 day lactation - 77,480 lbs. milk (35,145 kg) - Average of 212 lbs./day (96 kg./day)

3 The Modern Dairy Cow (2) This cow is housed in a herd of 94 cows fed a TMR. Herd average is 44,122 lbs. milk (20,013 kg.) Milk fat = 3.8% Milk true protein = 3.08

4 > 200,000 kg of milk -lifetime Average = 42 kg/day for every day in milk!

5 The Cow as a Biological Manufacturing Plant Inputs - - Feed and water Outputs - - Milk, meat Co-products - - Manure, heat, gases

6 Why Are We Concerned About Gas Emissions? Primary reason - - Gas emissions from the cow represent a loss of consumed nutrients to the environment. - The energy and protein lost in producing gases is not available for use in producing milk. - Milk production and efficiency of feed use are decreased. - Profits are decreased.

7 Why? (2) Secondary reason - - There are increasing government regulations for agriculture to lower emissions to the environment. - The dairy industry in the U.S. is being regulated on nitrogen and phosphorus on larger dairy farms. - Ammonia and methane regulations are probably the next targets for the dairy industry.

8 Sources of Ammonia Emissions in the US % of Total Emissions 9% 5% 10% Industry Cattle Human 27% 45% Poultry Swine Fert. 4%

9 Primary Sources of Air Emissions on Dairy Farms NH 3 NH 3 N 2 O CH4 H 2 S VOC NH3 PM CH4 PM Barn Open Lot Manure Storage Cropland L. T.

10 Primary Sources of Air Emissions on Dairy Farms NH 3 NO X NH 3 NH 3 N 2 O CH4 H 2 S VOC NH3 VOC PM CH4 PM Barn Open Lot Manure Storage Cropland L. T.

11 Primary Sources of Air Emissions on Dairy Farms NH 3 NO X NH 3 NH 3 N 2 O CH4 H 2 S VOC NH3 VOC PM CH4 PM Barn Open Lot Manure Storage Cropland L. T.

12 % of Nitrogen Intake Excreted in Milk % Milk, lbs/day

13 Liver Urine Feed Crude Protein Recycled Urea Milk Recycled Ammonia Carbohydrates Microbes VFA Manure Excess Protein Dr. M. B. Hall - Univ. of Florida Escape Feed Protein Rumen Production & Maintenance Absorbed Protein

14 Synchronizing Carbohydrate and Protein Release in the Rumen Fermentable carbohydrates Degradable protein Microbial protein Volatile fatty acids

15 Milk, Urine and Fecal N excretion, g/d Nitrogen Excretion in Milk, Feces and Urine Based on N Intake in Lactating Dairy Cattle Nitrogen Intake, g/d Milk N Urinary N Fecal N Source: Dr. M. Van Amburgh Cornell University

16 Nitrogen Intake and Excretion with Varying Ration CP g/day Ration CP, % N intake Manure N Olmos Colmenero and Broderick, 2006

17 Daily N Excretion g/day Milk Urine Fecal Ration CP, % Olmos Colmenero nd Broderick, 2006

18 NH3 g/day Daily Ammonia Emissions, g/day , ,5 17,9 19,4 Ration CP %

19 Milk Nitrogen Efficiency % Ration CP, % Olmos Colmenero and Broderick, 2006

20 NH3 g/day Ration CP and Ammonia Emissions, g N/cow/day Ration CP % Burgos et. al., 2010

21 Can We Reduce Ammonia Emissions? Growing dairy heifers ( lbs) Fed 2 TMR s ( 15 and 17.4% CP) N intake was reduced by 14% N excretion was reduced by 13% Ammonia emissions were reduced by 28% Not a growth trial

22 What About Dairy Cows? Broderick - - Lowering ration CP from 16.5 to 15% decreased ammonia emission by 20%. Burgos - Lowering ration CP from 17 to 15% decreased ammonia emissions by 37%.

23 How Do We Decrease Ammonia Emissions? There are a number of options - Decrease rumen degradable protein and shift to more rumen undegradable protein sources. - Increase rumen fermentable carbohydrates. - Select rumen degradable sources with lower rates of breakdown. - Match rates of digestion of protein and carbohydrate sources in the rumen. - Use multiple sources of protein and carbohydrate feed ingredients to get a more uniform pattern of NH3 and available carbohydrate in the rumen.

24 The Goal!

25 Feeding Management Feed an carbohydrate energy source before feeding the protein feed in component fed herds. Minimize slug feeding. Use feed management practices that encourage cows to eat more frequently and have smaller meals.

26 How Can We Monitor Ammonia Emissions on Farms? Practical direct measuring techniques are not available. Need to use indirect measures. One option is to use urinary N excretion - - A portion of the urinary N is converted to ammonia. - The % varies due to a number of factors. - A starting point used in C NCPS is to use a conversion factor of 65% g of urinary N = 65 g of ammonia. - Urinary N excretion is on a number of AMTS reports. Keep rumen NH3 between % of requirements.

27 Monitoring (2) Milk urea nitrogen can also be used as a monitoring tool. Routinely provided to dairy producers by many milk plants on the loads of milk shipped. Is an optional milk analysis that can be added for herds on the DHI (Dairy Herd Improvement) milk testing program.

28 Ration CP and MUN, mg/dl Burgos et. al., 2010

29 Milk Urea (mg/l) Relationship between rumen ammonia and milk urea (data from MTT studies) y = 18.4x + 87 R 2 = Rumen ammonia N (mmol/l

30 MUN Guidelines Range used in our New York Precision Feed Management program mg/dl Values > 12 indicate inefficiency of N use in the cow. Many high producing herds routinely have herd MUN values of 7 9 with high levels of reproductive efficiency. MUN values < 5-6 may indicate a shortage of ammonia in the rumen and could be limiting microbial protein synthesis and milk production.

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34 Conversion of feed into animal product methane heat faeces urine feed FCE = milk : feed intake milk

35 Methane/Gross energy intake (%) Methane Energy Loss Dry matter intake (kg/d) 30 Mills et al.,

36 U.S. GHG Emissions, MMT CO 2 Equiv CO2 CH4 N2O Source: U.S. EPA 2016

37 U.S. CH4 Emissions, MMT CO 2 Equiv ,2 164, Total Enteric Source: U.E. EPA 2016

38 U.S. Total GHG Emissions Other 89% Methane 11% Other Methane Source: U.S. EPA 2016

39 Sources of Methane Emissions Enteric CH4 emissions are 22.5% of total methane emissions. Enteric CH4 emissions are 2.4% of total U.S. greenhouse gas emissions. CH4 emissions from dairy cattle are 5.7% of total CH4 emissions. CH4 emissions from dairy cattle are 0.6% of total U.S. greenhouse gas emissions.

40 Where Does Methane Come From? Rumen fermentation yields H 2 Methanogenesis is a sink for H 2 C0 2 reduced to CH 4 Fermentation also occurs in hind gut Acetate Butyrate Propionate Valerate Microbial growth with amino acids H 2 Microbial growth with ammonia and in manure H 2 Source H 2 Sink Lipid Hydrogenation unsaturated fatty acids Methane EXCESS CO 2 + 4H 2 CH 4 +2H 2 O Zero pool scheme

41 How Do We Measure and Report Methane Emissions? Used the CNCPS 6.5 model. Ration was 53% forage, 47% concentrate. 56:44 corn silage to alfalfa silage (DM basis). 17.6% CP, 31.5% NDF, 26% starch, 4.7% fat.

42 Milk, lbs./day Methane Emissions CH 4, g/day CH 4, g/l. milk

43 How Much of the Total Herd Methane Emissions do Various Animal Groups Produce? (% of Total) Item Herd A Herd B Herd C Cows/Her d 150 1,200 1,500 Milk cows Dry cows Heifers

44 Commercial Dairy Herd Rations Database of 199 individual rations. All run through the CNCPS 6.5 program. Average milk production was 83.7 lbs. (range 50 to 128). Average DMI was 51.4 lbs. (range 35.2 to 69.8 lbs.).

45 Commercial Rations Results Correlation between DMI and CH4 emissions (g/day) = Correlation between DMI and CH4 emissions (g/lb. milk) was

46 How Can We Decrease CH 4 Emissions? Key opportunities: - Increase milk/cow - Decrease cow numbers - Improve feed efficiency - Decrease the number of nonproductive days.

47 Examples Milking frequency Reproductive efficiency bst Uniform grouping Healthy animals Transition cow management Ionophores More accurate ration formulation, mixing and delivery Forage quality Reduced age at 1 st calving

48 Potential Maximum Reductions in CH 4 /unit of ECM Genetic selection 18% Feeding and nutrition 15% Rumen modifiers 5% Other management strategies 18% All approaches combined 30% Approaches are not assumed to be additive Knaap et. al., 2014

49 Nutrition and Feeding Impacts on Change CH 4 Emissions Impact Increase DMI Decrease 2-6% for each 2.2 lb. increase Decrease forage particle size Processing of grain Neutral Decrease about 1-2.5% for a 5% increase in total tract starch digestibility Rumen ph <5.5 Decrease 15-20% Feeding more grain Decrease about 2% for a 1% increase in ration NFC Knapp et.al., 2014

50 Productivity Bell et. al., A 1 SD increase in feed efficiency could lower CO 2 equivalent emissions by 6.5%. rbst Could potentially lower methane emissions by 8.3% (Bauman and Capper, 2010).

51 Forages Higher quality forages have lower methane emissions. Replacing grass or legume forages with corn silage may lower methane emissions. The first step is to select forages to be grown based on farm agronomic and environmental considerations. The second step is to produce higher quality forages.

52 Other Herd Management Factors About 10-30% of total herd methane emissions are from dry cows and replacement heifers. Reducing age at 1 st calving by 2 months can lower herd methane emissions by 1.5%. Reducing culling rate by 5 units can lower herd methane emissions by 3.1% Dr. B. Weiss Ohio State

53 Garnsworthy (2004) Evaluated reproductive efficiency on methane and ammonia production in UK herds Compared current preg rate (19%) vs that in 1995 (25.5%) Evaluations also included replacement inventory and two levels of milk production 13,500 and 20,000 lb./year

54 Achieving a Higher Pregnancy Methane Rate 4 to 11% reduction per 100 cows Ammonia 4 to 9% reduction per 100 cows Garnsworthy, 2004

55 Hristov et. al Paper at 2015 ADSA meetings. 12 week trial with lactating cows. Milk production average was 100 lbs./day. Used 0, 40, 60 and 80 mg/kg feed of 3- nitrooxypropanol. Methane emissions were reduced by 25, 31 and 32%.

56 Economics A couple of recent papers have indicated that adjusting rations to lower methane emissions may increase feed costs and lower profitability. This area needs additional analyses. Will be related to relationships between milk price and feed costs. May be farm specific.

57 How to Really Decrease CH 4 Emissions Low forage and high corn silage. High starch ( >30%). High levels (>5%?) of unsaturated fats. Added nitrates. Added 3-NOP. Do You See Any Problems by Doing This?

58 Summary Long-term approaches - - Use of genomics and genetic selection to improve feed efficiency. - Alterations of rumen microbial population. - Added compounds that can alter rumen fermentation. - Altering herd management (replacements, reproduction).

59 Summary - 2 Short-term approaches - - Improve feed efficiency. - Using fiber and starch digestibility in balancing rations. - Utilizing feed additives and production technologies based on research data. - Forage type and quality.

60 Summary - 3 Providing feeding and management systems that improve cow comfort, herd health and reproductive performance. Precision feeding and consistency of feed mixing, delivery and feed bunk management.

61 Thanks!

62 Dr Mark Hanigan, PhD Virginia Tech Is there Really a single limiting Amino Acid?