Reducing dietary protein in dairy cow diets: Implications for nitrogen utilization, milk production, welfare and fertility

Animal

Volumn 8, Issue 2, 2014, Pages 262-274

  Sinclair, K D ^a   Garnsworthy, P C ^a   Mann, G E ^a   Sinclair, L A ^b  

^a UNIVERSITY OF NOTTINGHAM   (United Kingdom)

^b HARPER ADAMS UNIVERSITY   (United Kingdom)

Author keywords

CP; dairy cow; fertility; health; milk yield

Indexed keywords

BOS;

NITROGEN;

ANIMAL; ANIMAL FOOD; ANIMAL HUSBANDRY; ANIMAL WELFARE; ARTICLE; CATTLE; DAIRYING; DRUG EFFECT; FEMALE; FERTILITY; METABOLISM; METHODOLOGY; MILK; PHYSIOLOGY; PROTEIN INTAKE;

ANIMAL HUSBANDRY; ANIMAL NUTRITIONAL PHYSIOLOGICAL PHENOMENA; ANIMAL WELFARE; ANIMALS; CATTLE; DAIRYING; DIETARY PROTEINS; FEMALE; FERTILITY; MILK; NITROGEN;

EID: 84892816735     PISSN: 17517311     EISSN: 1751732X     Source Type: Journal    
DOI: 10.1017/S1751731113002139     Document Type: Article

References (123)

1. Aboozar M, Amanlou H, Aghazadeh AM, Adl KN, Moeini M and Tanha T 2012. Impacts of different jevels of RUP on performance and reproduction of Holstein fresh cows. Journal of Animal and Veterinary Advances 11, 1338-1345.
2. Allison RD and Garnsworthy PC 2002. Increasing the digestible undegraded protein intake of lactating dairy cows by feeding fishmeal or a rumen protected vegetable protein blend. Animal Feed Science and Technology 96, 69-81.
3. Archibeque SL, Freetly HC, Cole NA and Ferrell CL 2007. The influence of oscillating dietary protein concentrations on finishing cattle. II. Nutrient retention and ammonia emissions. Journal of Animal Science 85, 1496-1503.
4. Armentano LE, Swain SM and Ducharme GA 1993. Lactation response to ruminally protected methionine and lysine at two amounts of ruminally available nitrogen. Journal of Dairy Science 76, 2963-2969.
5. Bach A, Calsamiglia S, Huntington GB and Stern MD 2000. Nitrogen metabolism of early lactation cows fed diets with two different levels of protein and different amino acid profiles. Journal of Dairy Science 83, 2585-2595.
6. Barton BA, Rosario HA, Anderson GW, Grindle BP and Carroll DJ 1996. Effects of dietary crude protein, breed, parity, and health status on the fertility of dairy cows. Journal of Dairy Science 79, 2225-2236.
7. Bazeley K and Pinsent PJN 1984. Preliminary observations on a series of outbreaks of acute laminitis in dairy cattle. Veterinary Record 115, 619-622.
8. Bertics SJ and Grummer RR 1999. Effects of fat and methionine hydroxy analog on prevention or alleviation of fatty liver induced by feed restriction. Journal of Dairy Science 82, 2731-2736.
9. Bobe G, Young JW and Beitz DC 2004. Invited review: pathology, etiology, prevention, and treatment of fatty liver in dairy cows. Journal of Dairy Science 87, 3105-3124.
10. Botts RL, Hemken RW and Bull LS 1979. Protein reserves in the lactating dairy cow. Journal of Dairy Science 62, 433-440.
11. Broderick GA 2003. Effects of varying dietary protein and energy levels on the production of lactating dairy cows. Journal of Dairy Science 86, 1370-1381.
12. Bruckental I, Droiri D, Kaim M, Lehrer H and Folman Y 1989. Effects of source and level of protein on milk yield and reproductive performance of high-producing primiparous and multiparous dairy cows. Animal Production 48, 319-329.
13. Butler ST, Shalloo L and Murphy JJ 2010. Extended lactations in a seasonalcalving pastoral system of production to modulate the effects of reproductive failure. Journal of Dairy Science 93, 1283-1295.
14. Butler WR 1998. Optimizing protein nutrition for reproduction and lactation. Effect of protein nutrition on ovarian and uterine physiology in dairy cattle. Journal of Dairy Science 81, 2533-2539.
15. Butler WR, Calaman JJ and Beam SW 1996. Plasma and milk urea nitrogen in relation to pregnancy rate in lactating dairy cattle. Journal of Animal Science 74, 858-865.
16. Cabrita ARJ, Dewhurst RJ, Melo DSP, Moorby JM and Fonseca AJM 2011. Effects of dietary protein concentration and balance of absorbable amino acids on productive responses of dairy cows fed corn silage-based diets. Journal of Dairy Science 94, 4647-4656.
17. Cadórniga C and López Díaz MC 1995. Possible modulation of adipose tissue responsivesness to catecholamines by available dietary protein in dairy cows during early lactation. Reproduction Nutrition Development 35, 241-248.
18. Canale CJ, Muller LD, McCahon HA, Whitsel TJ, Varga GA and Lormore MJ 1990. Dietary fat and ruminally protected amino acids for high producing dairy cows. Journal of Dairy Science 73, 135-141.
19. Cant JP, Depeters EJ and Baldwin RL 1991. Effect of dietary-fat and postruminal casein administration on milk-composition of lactating dairy-cows. Journal of Dairy Science 74, 211-219.
20. Carroll DJ, Barton BA, Anderson GW and Smith RD 1988. Influence of protein intake and feeding strategy on reproductive performance of dairy cows. Journal of Dairy Science 71, 3470-3481.
21. Chew KH 1972. Subacute/chronic laminitis and sole ulceration in a dairy herd. Canadian Veterinary Journal 13, 90-93.
22. Chow JM, DePeters EJ and Baldwin RL 1990. Effect of rumen-protected methionine and lysine on casein in milk when diets high in fat or concentrate are fed. Journal of Dairy Science 73, 1051-1061.
23. Christensen RA, Cameron MR, Clark JH, Drackley JK, Lynch JM and Barbano DM 1994. Effects of amount of protein and ruminally protected amino acids in the diet of dairy cows fed supplemental fat. Journal of Dairy Science 77, 1618-1629.
24. Clark AK and Rakes AH 1982. Effect of methionine hydroxy analog supplementation on dairy cattle hoof growth and composition. Journal of Dairy Science 65, 1493-1502.
25. Cole NA 1999. Nitrogen retention by lambs fed oscillating dietary protein concentrations. Journal of Animal Science 77, 215-222.
26. Cole NA and Todd RW 2008. Opportunities to enhance performance and efficiency through nutrient synchrony in concentrate-fed ruminants. Journal of Animal Science 86, E318-E333.
27. Colin-Schoellen O, Laurent F, Vignon B, Robert JC and Sloan B 1995. Interactions of ruminally protected methionine and lysine with protein source or energy level in the diets of cows. Journal of Dairy Science 78, 2807-2818.
28. Colmenero JJ and Broderick GA 2006. Effect of dietary crude protein concentration on milk production and nitrogen utilization in lactating dairy cows. Journal of Dairy Science 89, 1704-1712.
29. Cottrill B, Biggadike HJ, Collins C and Laven RA 2002. Relationship between milk urea concentration and the fertility of dairy cows Source. Veterinary Record 151, 413-416.
30. Curtis CR, Erb HN, Sniffen CJ, Smith RD and Kronfield DS 1985. Path analysis of dry period nutrition, postpartum metabolic and reproductive disorders, and mastitis in Holstein cows. Journal of Dairy Science 68, 2347-2360.
31. Davidson S, Hopkins BA, Diaz DE, Bolt SM, Brownie C, Fellner V and Whitlow LW 2003. Effects of amounts and degradability of dietary protein on lactation, nitrogen utilization, and excretion in early lactation Holstein cows. Journal of Dairy Science 86, 1681-1689.
32. De Wit AA, Cesar ML and Kruip TA 2001. Effect of urea during in vitro maturation on nuclear maturation and embryo development of bovine cumulusoocyte-complexes. Journal of Dairy Science 84, 1800-1804.
33. Donaldson J, van Houtert MFJ and Sykes AR 2001. The effect of dietary fish-meal supplementation on parasite burdens of periparturient sheep. Animal Science 72, 149-158.
34. Durand D, Chilliard Y and Bauchart D 1992. Effects of lysine and methionine on in vivo hepatic secretion of VLDL in the high yielding dairy cow. Journal of Dairy Science 75 (Suppl. 1), 279 (Abstract).
35. Edwards JS, Bartley E and Dayton AD 1980. Effects of dietary protein concentration on lactating cows. Journal of Dairy Science 63, 243-248.
36. Elrod CC and Butler WR 1993. Reduction of fertility and alteration of uterine pH in heifers fed excess ruminally degradable protein. Journal of Animal Science 71, 694-701.
37. Espejo LA and Endres MI 2007. Herd-level risk factors for lameness in highproducing Holstein cows housed in freestall barns. Journal of Dairy Science 90, 306-314.
38. Faverdin P 1999. The effect of nutrients on feed intake in ruminants. Proceedings of the Nutrition Society 58, 523-531.
39. Friggens NC, Andersen JB, Larsen T, Aaes O and Dewhurst RJ 2004. Priming the dairy cow for lactation: a review of dry cow feeding strategies. Animal Research 53, 453-473.
40. Galbraith H and Scaife JR 2007. Lameness in dairy cows: influence of nutrition on claw composition and health. In Recent advances in animal nutrition (ed. PC Garnswothy and J Wiseman), pp. 91-126. Nottingham University Press, Nottingham, UK.
41. Garcia-Bojalil CM, Staples CR, Risco CA, Savio JD and Thatcher WW 1998. Protein degradability and calcium salts of long-chain fatty acids in the diets of lactating dairy cows: reproductive responses. Journal of Dairy Science 81, 1385-1395.
42. Garnsworthy PC and Jones GP 1987. The influence of body condition at calving and dietary protein supply on voluntary food intake and performance in dairy cows. Animal Production 44, 347-353.
43. Garnsworthy PC, Gong JG, Armstrong DG, Newbold JR, Marsden M, Richards SE, Mann GE, Sinclair KD and Webb R 2008. Nutrition, metabolism and fertility in dairy cows: 3. Amino acids and ovarian function. Journal of Dairy Science 91, 4190-4197.
44. Goff J 2003. Managing the transition cow-considerations for optimising energy and protein balance, and immune function. Cattle Practice 11, 51-63.
45. Greenfield RB, Cecava MJ, Hohnson TR and Donkin SS 2000. Impact of dietary protein amount and rumen undegradability on intake, peripartum liver tryglyceride, plasma metabolites, and milk production in transition dairy cattle. Journal of Dairy Science 83, 703-710.
46. Grummer RR 1995. Impact of changes in organic nutrient metabolism on feeding the transition dairy cow. Journal of Animal Science 73, 2820-2833.
47. Hepburn NL, Knight CH, Wilde CJ, Hendry KAK and Galbraith H 2008. L-methionine uptake, incorporation and effects on proliferative activity and protein synthesis in bovine claw tissue explants in vitro. Journal of Agricultural Science 146, 103-115.
48. Herrera-Saldana R, Gomez-Alarcon R, Torabi M and Huber JT 1990. Influence of synchronizing protein and starch degradation in the rumen on nutrient utilization and microbial protein synthesis. Journal of Dairy Science 73, 142-148.
49. Hongerholt DD and Muller LD 1998. Supplementation of rumen-undegradable protein to the diets of early lactation Holstein cows on grass pasture. Journal of Dairy Science 81, 2204-2214.
50. Howard HJ, Aalseth EP, Adams GD and Bush LJ 1987. Influence of dietary protein on reproductive performance of dairy cows. Journal of Animal Science 70, 1563-1571.
51. Hristov AN, Price WJ and Shafii B 2004. A meta-analysis examining the relationship among dietary factors, dry matter intake, and milk and milk protein yield in dairy cows. Journal of Dairy Science 87, 2184-2196.
52. Huhtanen P and Hristov AN 2009. A meta-analysis of the effects of dietary protein concentration and degradability on milk protein yield and milk N efficiency in dairy cows. Journal of Dairy Science 92, 3222-3222.
53. Huhtanen P, Rinne M and Nousiainen J 2008. Evaluation of concentrate factors affecting silage intake of dairy cows: a development of the relative total diet intake index. Animal 2, 942-953.
54. Huyler MT, Kincaid RL and Dostal DF 1999. Metabolic and yield responses of multiparous Holstein cows to prepartum rumen-undegradable protein. Journal of Dairy Science 82, 527-536.
55. Ingvartsen KL and Andersen JB 2000. Integration of metabolism and intake regulation: a review focusing on periparturient animals. Journal of Dairy Science 83, 1573-1597.
56. Ipharraguerre IR and Clark JH 2005. Impacts of the source and amount of crude protein on the intestinal supply of nitrogen fractions and performance of dairy cows. Journal of Dairy Science 88 (Suppl. 1), E22-E37.
57. Jones GP and Garnsworthy PC 1988. The effects of body condition score at calving and dietary protein content on dry-matter intake and performance in lactating dairy cows given diets of low energy content. Animal Production 47, 321-333.
58. Jonker JS, Kohn RA and High J 2002. Dairy herd management practices that impact nitrogen utilization efficiency. Journal of Dairy Science 85, 1218-1226.
59. Jordan ER and Swanson LV 1979. Effect of crude protein on reproductive efficiency, serum total protein, and albumin in the high-producing dairy cow. Journal of Dairy Science 62, 58-63.
60. Jorritsma R, Jorritsma H, Schukken YH and Wentink GH 2000. Relationships between fatty liver and fertility and some periparturient diseases in commercial Dutch dairy herds. Theriogenology 54, 1065-1074.
61. Kehrli ME and Shuster DE 1994. Factors affecting milk somatic cells and their role in health of the bovine mammary gland. Journal of Dairy Science 77, 619-627.
62. Kokkonen T, Syrjälä-Qvist L, Tsehai Tesfa A, Tuori M and Yrjänen S 2002. Effect of concentrate crude protein level on grass silage intake, milk yield and nutrient utilisation by dairy cows in early lactation. Archives of Animal Nutrition 56, 213-227.
63. Kolver ES, Roche JR, Burke CR, Kay JK and Aspin PW 2007. Extending lactation in pature-based dairy cows: I. Genotype and diet effect on milk and reproduction. Journal of Dairy Science 90, 5518-5530.
64. Laven RA and Livesey CT 2004. The effect of housing and methionine intake on hoof horn hemorrhages in primiparous lactating Holstein cows. Journal of Dairy Science 87, 1015-1023.
65. Law RA, Young FJ, Patterson DC, Kilpatrick DJ, Wylie AR and Mayne CS 2009a. Effect of dietary protein content on animal production and blood metabolites of dairy cows during lactation. Journal of Dairy Science 92, 1001-1012.
66. Law RA, Young FJ, Patterson DC, Kilpatrick DJ, Wylie ARG and Mayne CS 2009b. Effect of dietary protein content on the fertility of dairy cows during early and mid lactation. Journal of Dairy Science 92, 2737-2746.
67. Lean IJ, Celi P, Raadsma H, McNamara J and Rabiee AR 2012. Effects of dietary crude protein on fertility: meta-analysis and meta-regression. Animal Feed Science and Technology 171, 31-42.
68. Lee C, Hristov AN, Heyler KS, Cassidy TW, Long M, Corl BA and Karnati SK 2011. Effects of dietary protein concentration and coconut oil supplementation on nitrogen utilization and production in dairy cows. Journal of Dairy Science 94, 5544-5557.
69. Lee C, Hristov AN, Heyler KS, Cassidy TW, Lapierre H, Varga GA and Parys C 2012a. Effects of metabolizable protein supply and amino acid supplementation on nitrogen utilization, milk production, and ammonia emissions from manure in dairy cows. Journal of Dairy Science 95, 5253-5268.
70. Lee C, Hristov AN, Cassidy TW, Heyler KS, Lapierre H, Varga GA, de Veth MJ, Patton RA and Parys C 2012b. Rumen-protected lysine, methionine, and histidine increase milk protein yield in dairy cows fed a metabolizable proteindeficient diet. Journal of Dairy Science 95, 6042-6056.
71. Livesey CT and Laven RA 2007. Effects of housing and intake of methionine on the growth and wear of hoof horn and the conformation of the hooves of firstlactation Holstein heifers. Veterinary Record 160, 470-476.
72. Mann GE, Mann SJ, Blache D and Webb R 2005. Metabolic variables and plasma leptin concentrations in dairy cows exhibiting reproductive cycle abnormalities identified through milk progesterone monitoring during the post partum period. Animal Reproduction Science 88, 191-202.
73. Manson FJ, Leaver JD 1988. The influence of dietary protein intake and of hoof trimming on lameness in dairy cattle. Animal Production 47, 191-199.
74. Metcalf JA, Mansbridge RJ, Blake JS, Oldham JD, Newbold JR 2008. The efficiency of conversion of metabolisable protein into milk true protein over a range of metabolisable protein intakes. Animal 2, 1193-1202.
75. Momcilovic D, Herbein JH, Whittier WD and Polan CE 2000. Metabolic alterations associated with an attempt to induce laminitis in dairy calves. Journal of Dairy Science 83, 518-525.
76. Nachtomi E, Halem A, Bruckental I and Amir S 1991. Energy-protein intake and its effect on blood metabolites of high-producing dairy cows. Canadian Journal of Animal Science 71, 401-401.
77. National Research Council (NRC) 2001. Nutrient requirements of dairy cattle, 7th Revised Edition. National Academy Press, Washington, DC, USA.
78. Newbold JR 1994. Practical application of the metabolisable protein system. In Recent advances in animal nutrition (ed. PC Garnsworthy and DJA Cole), pp. 231-264. Nottingham University Press, Nottingham.
79. Nilsson SA 1963. Clinical, morphological and experimental studies of laminitis in cattle. Acta Veterinaria Scandinavica 4, 299-304.
80. Noftsger S and St-Pierre NR 2003. Supplementation of methionine and selection of highly digestible rumen undegradable protein to improve nitrogen efficiency for milk production. Journal of Dairy Science 86, 958-969.
81. Ocon OM and Hansen PJ 2003. Disruption of bovine oocytes and preimplantation embryos by urea and acidic pH. Journal of Dairy Science 86, 1194-1200.
82. Offer JE, Logue DN and Roberts DJ 1997. The effect of protein source on lameness and solear lesion formation in dairy cattle. Animal Science 65, 143-149.
83. Oldham JD 1984. Protein-energy interrelationships in dairy cows. Journal of Dairy Science 67, 1090-1114.
84. Paquay R, DeBaere R and Bull LS 1972. The capacity of the mature cow to lose and recover nitrogen and the significance of body reserves. British Journal of Nutrition 27, 27-37.
85. Patton RA 2010. Effect of rumen-protected methionine on feed intake, milk production, true milk protein concentration, and true milk protein yield, and the factors that influence these effects: a meta-analysis. Journal of Dairy Science 93, 2105-2118.
86. Piepenbrink MS, Overton TR and Clark JH 1996. Response of cows fed a low crude protein diet to ruminally protected methionine and lysine. Journal of Dairy Science 79, 1638-1646.
87. Piepenbrink MS, Marr AL, Waldron MR, Butler WR, Overton TR, Vázquez-Añón M and Holt MD 2004. Feeding 2-hydroxy-4-(methylthio)-butanoic acid to peripartiurient dairy cows improves milk production but not hepatic metabolism. Journal of Dairy Science 87, 1071-1084.
88. Polan CE, Cummins KA, Sniffen CJ, Muscato TV, Vicini JL, Crooker BA, Clark JH, Johnson DG, Otterby DE and Guillaume B 1991. Responses of dairy cows to supplemental rumen-protected forms of methionine and lysine. Journal of Dairy Science 74, 2997-3013.
89. Preynat A, Lapierre H, Thivierge MC, Palin MF, Cardinault N, Matte JJ, Desrochers A and Girard CL 2010. Effects of supplementary folic acid and vitamin B12 on hepatic metabolism of dairy cows according to methionine supply. Journal of Dairy Science 93, 2130-2142.
90. Putnam DE and Varga GA 1998. Protein density and its influence on metabolite concentration and nitrogen retention by Holstein cows in late gestation. Journal of Dairy Science 81, 1608-1618.
91. Putnam DE, Varga GA and Dann HM 1999. Metabolic and production responses to dietary protein and exogenous somatotrophin in late gestation dairy cows. Journal of Dairy Science 82, 982-995.
92. Reynolds CK and Kristensen NB 2008. Nitrogen recycling through the gut and the nitrogen economy of ruminants: an asynchronous symbiosis. Journal of Animal Science 86, E293-E305.
93. Rhoads ML, Rhoads RP, Gilbert RO, Toole R and Butler WR 2006. Detrimental effects of high plasma urea nitrogen levels on viability of embryos from lactating dairy cows. Animal Reproduction Science 91, 1-10.
94. Robert JC 2005. Metabolizable methionine optimization of dairy cow rations. In Recent advances in animal nutrition 2004 (ed. PC Garnsworthy and J Wiseman), pp. 223-254. University of Nottingham Feed Manufacturers Conference, Nottingham, UK.
95. Robinson PH 2010. Impacts of manipulating ration metabolizable lysine and methionine levels on the performance of lactating dairy cows: a systematic review of the literature. Livestock Science 127, 115-126.
96. Robinson PH, Swanepoel N and Evans E 2010. Effects of feeding a ruminally protected lysine product, with or without isoleucine, valine and histidine, to lactating dairy cows on their productive performance and plasma amino acid profiles. Animal Feed Science and Technology 161, 75-84.
97. Robinson PH, Fredeen AH, Chalupa W, Julien WE, Sato H, Fujieda T and Suzuki H 1995. Ruminally protected lysine and methionine for lactating dairy cows fed a diet designed to meet requirements for microbial and postruminal protein. Journal of Dairy Science 78, 582-594.
98. Robinson PH, Chalupa W, Sniffen CJ, Julien WE, Sato H, Watanabe K, Fujieda T and Suzuki H 1998. Ruminally protected lysine or lysine and methionine for lactating dairy cows fed a ration designed to meet requirements for microbial and postruminal protein. Journal of Dairy Science 81, 1364-1373.
99. Robinson PH, Chalupa W, Sniffen CJ, Julien WE, Sato H, Fujieda T, Ueda T and Suzuki H 2000. Influence of abomasal infusion of high levels of lysine or methionine, or both, on ruminal fermentation, eating behavior, and performance of lactating dairy cows. Journal of Animal Science 78, 1067-1077.
100. Rode LM, Fujeieda T, Sato H, Suzuki H, Julien WE and Sniffen CJ 1994. Rumenprotected amino acid (RPAA) supplementation to dairy cows pre-and postparturition. Journal of Dairy Science 77, 243 (Abstract).
101. Rogers JA, Krishnamoorthy U and Sniffen CJ 1987. Plasma amino acids and milk protein production by cows fed rumen-protected methionine and lysine. Journal of Dairy Science 70, 789-798.
102. Rogers JA, Peirce-Sandner SB, Papas AM, Polan CE, Sniffen CJ, Muscato TV, Staples CR and Clark JH 1989. Production responses of dairy cows fed various amounts of rumen-protected methionine and lysine. Journal of Dairy Science 72, 1800-1817.
103. Sawa A, Bogucki M and Krezel-Czopek S 2011. Effect of some factors on relationships between milk urea levels and cow fertility. Archiv Fur Tierzucht-Archives of Animal Breeding 54, 468-476.
104. Schei I, Volden H and Baevre L 2005. Effects of energy balance and metabolizable protein level on tissue mobilization and milk performance of dairy cows in early lactation. Livestock Production Science 95, 35-47.
105. Schor A and Gagliostro GA 2001. Undegradable protein supplmenetation to early-lactation dairy cows in grazing conditions. Journal of Dairy Science 84, 1597-1606.
106. Shibano K and Kawamura S 2006. Serum free amino acid concentrations in hepatic lipidosis of dairy cows in the periparturient period. Journal of Veterinary Medical Science 68, 393-396.
107. Sinclair KD, Broadbent PJ and Hutchinson JSM 1994. The effect of pre-and postpartum energy and protein supply on the blood metabolites and reproductive performance of single-and twin-suckling beef cows. Animal Production 59, 391-400.
108. Sinclair KD, Sinclair LA and Robinson JJ 2000a. Nitrogen metabolism and fertility in cattle: I. Adaptive changes in intake and metabolism to diets differing in their rate of energy and nitrogen release in the rumen. Journal of Animal Science 78, 2659-2669.
109. Sinclair KD, Kuran M, Gebbie FE, Webb R and McEvoy TG 2000b. Nitrogen metabolism and fertility in cattle: II. Development of oocytes recovered from heifers offered diets differing in their rate of nitrogen release in the rumen. Journal of Animal Science 78, 2670-2680.
110. Sinclair LA, Blake CW, Griffin P and Jones GH 2012. The partial replacement of soyabean meal and rapeseed meal with feed grade urea or a slow-release urea and its effect on the performance, metabolism and digestibility in dairy cows. Animal 6, 920-927.
111. Soder KJ and Holden LA 1999. Lymphocyte proliferation response of lactating dairy cows fed varying concentrations of rumen-protected methionine. Journal of Dairy Science 82, 1935-1942.
112. Tarlton JF, Holah DE, Evans KM, Jones S, Pearson GR and AJF Webster 2002. Biochemical and histopathological changes in the support structures of bovine hooves around the time of first calving. The Veterinary Journal 163, 196-204.
113. Thomas C 2004. Feed into milk: a new applied feeding system for dairy cows. Nottingham University Press, Nottingham.
114. Twigge JR and van Gils LGM 1984. Practical aspects of feeding protein to dairy cows. In Recent advances in animal nutrition (ed. W Haresign and DJA Cole), pp. 201-217. Butterworths, London, UK.
115. Vandehaar MJ, Yousif G, Sharma BK, Herdt TH, Emery RS, Allen MS and Liesman JS 1999. Effect of energy and protein density of prepartum diets on fat and protein metabolism of dairy cattle in the periparturient period. Journal of Dairy Science 82, 1282-1295.
116. Vanhatalo A, Huhtanen P, Toivonen V and Varvikko T 1999. Response of dairy cows fed grass silage diets to abomasal infusions of histidine alone or in combinations with methionine and lysine. Journal of Dairy Science 82, 2674-2685.
117. Vyas D and Erdman RA 2009. Meta-analysis of milk protein yield responses to lysine and methionine supplementation. Journal of Dairy Science 92, 5011-5018.
118. Wall E, Coffey MP and Pollott GE 2012. The effect of lactation length on greenhouse gas emissions from the national herd. Animal 6, 1857-1867.
119. Wathes DC, Bourne N, Cheng Z, Mann GE, Taylor VJ and Coffey MP 2007. Multiple correlation analyses of metabolic and endocrine profiles with fertility in primiparous and multiparous cows. Journal of Dairy Science 90, 1310-1325.
120. Westwood CT, Bramley E and Lean IJ 2003. Review of the relationship between nutrition and lameness in pasture-fed dairy cattle. New Zealand Veterinary Journal 51, 208-218.
121. Westwood CT, Lean IJ, Garvin JK and Wynn PC 2000. Effects of genetic merit and varying dietary protein degradability on lactating dairy cows. Journal of Dairy Science 83, 2926-2940.
122. Wu Z and Satter LD 2000. Milk production during the complete lactation of dairy cows fed diets containing different amounts of protein. Journal of Dairy Science 83, 1042-1051.
123. Yan T, Mayne CS, Gordon FG, Porter MG, Agnew RE, Patterson DC, Ferris CP and Kilpatrick DJ 2010. Mitigation of enteric methane emissions through improving efficiency of energy utilization and productivity in lactating dairy cows. Journal of Dairy Science 93, 2630-2638.