Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-23T04:38:26.987Z Has data issue: false hasContentIssue false
  • English
  • Français

The efficiency of conversion of metabolisable protein into milk true protein over a range of metabolisable protein intakes

Published online by Cambridge University Press:  01 August 2008

J. A. Metcalf ,
R. J. Mansbridge ,
J. S. Blake ,
J. D. Oldham  and
J. R. Newbold
J. A. Metcalf*
Affiliation:
ADAS Bridgets, Martyr Worthy, Winchester, Hampshire SO21 1AP, UK
R. J. Mansbridge
Affiliation:
ADAS Bridgets, Martyr Worthy, Winchester, Hampshire SO21 1AP, UK
J. S. Blake
Affiliation:
ADAS Bridgets, Martyr Worthy, Winchester, Hampshire SO21 1AP, UK
J. D. Oldham
Affiliation:
Scottish Agricultural Colleges, Bush Estates, Penicuik, Midlothian EH26 0QE, UK
J. R. Newbold
Affiliation:
BOCM PAULS, 47 Key Street, Ipswich, Suffolk IP4 1BX, UK
*
E-mail: john.metcalf@nutreco.ca
Get access

Abstract

The aim of this work was to test the robustness of the 0.68 estimate of the efficiency of conversion of metabolisable protein into true milk protein (Agriculture and Food Research Council (AFRC), 1993) for protein-limiting diets and to determine whether a different value is appropriate for practical rationing. Seventy-two multiparous cows were blocked on the basis of milk energy output per unit of dry matter intake (DMI), and allocated at random to one of four treatments. Treatments supplied metabolisable energy (ME) at a fixed level to individuals within a block, but varied metabolisable protein (MP) supply from 25% below the estimated requirements, through −12.5% and +12.5% up to 25% above requirements for the average performance of animals within blocks at the start of the study. Cows were offered diets to meet their predicted ME requirements for each 3-week period with measurements performed in the last week of each period. Milk protein output was regressed against the estimated MP available for production for each cow and the efficiency of conversion of MP into milk true protein was calculated, assuming a maintenance requirement according to the MP system. The efficiency of conversion of MP into milk true protein decreased with the increasing supply of MP from 0.77 to 0.50. Using an iterative approach to determine the best fit of the data when supply matched requirement resulted in a range of efficiency values between 0.62 and 0.64 g of true milk protein per g of MP.

Keywords

dairy cowsmetabolisable proteinmetabolisable energynutrition
Type
Full Paper
Information
animal , Volume 2 , Issue 8 , August 2008 , pp. 1193 - 1202
Copyright
Copyright © The Animal Consortium 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Agriculture and Food Research Council 1990. Technical Committee on Responses to Nutrients, Report No. 5. Nutritive Requirements of Ruminant Animals: Energy. Nutrition Abstracts and Reviews Series B 60, 729–804.Google Scholar
Agriculture and Food Research Council 1992. Technical Committee on Responses to Nutrients, Report No. 9. Nutritive Requirements of Ruminant Animals: Energy. Nutrition Abstracts and Reviews Series B 62, 787–835.Google Scholar
Agriculture and Food Research Council 1993. Energy and protein requirements of ruminants. An advisory manual prepared by the AFRC Technical Committee on Responses to Nutrients. CAB International, Wallingford, UK.Google Scholar
Bequette, BJ, Metcalf, JA, Wray-Cahen, D, Backwell, FRC, Sutton, JD, Lomax, MA, MacRae, JA, Lobley, GE 1996. Leucine and protein metabolism in the lactating dairy cow mammary gland: responses to supplemental dietary crude protein intake. Journal of Dairy Research 63, 209–222.CrossRefGoogle ScholarPubMed
Forbes, JM 2007. Voluntary food intake and diet selection in farm animals, 2nd edition. CABI, Wallingford.CrossRefGoogle Scholar
Givens DI, Rymer C, Cottrill BR, Offer NW and Thomas C 2004. In Feed in to Milk: An advisory manual (ed. C Thomas), pp. 41–59. Nottingham University Press, Nottingham.Google Scholar
Hof, G, Tamminga, SLenaers, PJ 1994. Efficiency of protein utilization in dairy cows. Livestock Production Science 38, 169–178.CrossRefGoogle Scholar
International Dairy Federation 1993. Standard 20B: milk, Determination of Nitrogen content. International Dairy Federation, Brussels, UK.Google Scholar
Institut National de la Recherche Agronomique 1988. Alimentation des Bovins, Ovines, et Caprins (ed. R Jarrige). Paris, INRA, p. 370.Google Scholar
Jarrige, R, Alderman, G (eds) 1987. Feed evaluation and protein requirement systems for ruminants. CEC, Luxembourg, 328pp.Google Scholar
Krishnamoorthy, U, Muscato, TV, Sniffen, CJ, Van Soest, PJ 1982. Nitrogen fractions in selected feedstuffs. Journal of Dairy Science 65, 217–225.CrossRefGoogle Scholar
Livesey, CT, Harrington, T, Johnston, AM, May, SA, Metcalf, JA 1998. The effect of diet and housing on the development of sole haemorrhages, white line haemorrhages and heel erosions in Holstein heifers. Animal Science 67, 9–16.CrossRefGoogle Scholar
Madsen, J 1985. The basis for the Nordic protein evaluation system for ruminants. The AAT-PBV system. Acta Agriculture Scandinavica Suppl 25, 9–20.Google Scholar
Metcalf, JA, Mansbridge, RJ, Blake, JS, Newbold, JR, Oldham, JD 1997. Examining the Metabolisable Protein system at ideal protein: energy ratios in dairy cows. Proceedings of the British Society of Animal Science 83.Google Scholar
Moorby, JM, Dewhurst, RJ, Thomas, C, Marsden, S 1996. The influence of dietary energy source and dietary protein level on milk protein concentration from dairy cows. Animal Science 63, 1–10.CrossRefGoogle Scholar
National Research Council 1985. Ruminant Nitrogen Usage. Committee on Animal Nutrition, Board of Agriculture, National Research Council, Washington DC. National Academy Press.Google Scholar
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.Google Scholar
Newbold, JR, Cottrill, BR, Mansbridge, RJ, Blake, JS 1994. Effect of metabolisable protein on silage intake and milk protein yield in dairy cows. Animal Production 58, 455.Google Scholar
Nousiainen, J, Shingfield, KJ, Huhtanen, P 2004. Evaluation of milk urea nitrogen as a diagnostic of protein feeding. Journal of Dairy Science 87, 386–398.CrossRefGoogle ScholarPubMed
Oldham, JD 1984. Protein-energy interrelationships in dairy cows. Journal of Dairy Science 67, 1090–1114.CrossRefGoogle ScholarPubMed
Oldham, JD 1987. Efficiencies of amino acid utilisation. In Feed evaluation and protein requirement systems for ruminants (ed. R Jarrige and G Alderman), pp. 171–186. CEC, Luxemborg.Google Scholar
Porter MG, Patterson DC, Steen RWJ, Gordon FJ, 1984. Proceedings of the 7th Silage Conference, Paper 45. Queen’s University of Belfast, UK.Google Scholar
Subnel, AP, Meijer, RGM, van Straalen, WM, Tamminga, S 1994. Efficiency of milk protein production in the DVE protein evaluation system. Livestock Production Science 40, 215–224.CrossRefGoogle Scholar
Tamminga, S, van Straalen, WM, Subnel, APJ, Meijer, RGM, Steg, A, Wever, CJG, Blok, MC 1994. The Dutch protein evaluation system; the DVE/OEB system. Livestock Production Science 40, 139–155.CrossRefGoogle Scholar
Van Straalen, WM, Salaun, C, Ven, WAG, Rijpkema, VS, Hof, G, Boxem, TJ 1994. Validation of protein evaluation systems by means of milk production experiments with dairy cows. Netherlands Journal of Agricultural Science 42, 89–104.CrossRefGoogle Scholar
Vérité, R, Delaby, L 2000. Relation between nutrition, performances and nitrogen excretion in dairy cows. Annales de Zootechnie 49, 217–230.CrossRefGoogle Scholar