Hostname: page-component-586b7cd67f-g8jcs Total loading time: 0 Render date: 2024-11-26T20:13:40.013Z Has data issue: false hasContentIssue false
  • English
  • Français

The optimum level of protein in the supplement for dairy cows with access to grass silage

Published online by Cambridge University Press:  02 September 2010

F. J. Gordon  and
C. H. McMurray
F. J. Gordon
Affiliation:
Agricultural Research Institute of Northern Ireland, Hillsborough, Co. Down
C. H. McMurray
Affiliation:
Veterinary Research Laboratory, Stoney Road, Stormont, Belfast BT4
Get access

Abstract

Grass silage with a dry-matter content of 19·4% and containing 16·7% crude protein was offered ad libitum to 42 first lactation British Friesian cows during the first 75 days post-calving. In addition the animals received supplementary concentrates containing either 10·3, 13·6, 17·3, 21·1, 25·2 or 30·3% crude protein on a fresh weight basis, with extracted soya bean meal being used as the main protein source. All concentrates were offered at an equal level of 8·0 kg per day. The relationship between milk yield and protein content of the supplement was curvilinear and was described by the following equation:

Y= 8·95+ 1·0×–0·0205×

where Y = milk yield per day in kg, and × = percentage protein in the supplement. This equation indicated that maximum milk yield was obtained with a concentrate containing 24·4 % protein on a fresh weight basis. The protein content of the milk was also curvilinearly affected by the level of protein in the supplement, and it was calculated that maximum milk protein (nitrogen × 6·38) would be obtained with a supplement containing 23·9% protein. Plasma blood urea levels increased linearly with increasing protein intake. The effects on live-weight change and blood components were also recorded.

Type
Research Article
Information
Animal Production , Volume 29 , Issue 3 , December 1979 , pp. 283 - 291
Copyright
Copyright © British Society of Animal Science 1979

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

REFERENCES

Broster, W. H. 1972. Protein requirements of cows for lactation. In Handbuch der Tierernahrung (ed. Lenkeit, W., Breirem, K., Crasemann, E.), Vol. 2, pp. 292–322. Parey, Hamburg.Google Scholar
Butler, T. M. 1972. Sources and levels of proteins in cattle feeds. Ir. Grassld Anim. Prod. Assoc. J. 8: 24–31.Google Scholar
Butler, T. M. and Gleeson, P. A. 1973. Energy and protein supplementation of grass silage for lactating cows. An Foras Talüntais Anim. Prod. Res. Rep., pp. 98–99 (Abstr.).Google Scholar
Cuthbert, N. H., Thickett, W. S. and Wilson, P. N. 1973. The effect of varying protein level in a compound diet fed in conjunction with grass silage. Proc. Br. Soc. Anim. Prod. (New Series) 2: 70 (Abstr.).Google Scholar
Gordon, F. J. 1977a. Comparison of results from long term dairy cattle feeding experiments with calculated N-requirements. In Proc. 2nd. int. Symp. Protein Metabolism and Nutrition, pp. 142–146.Google Scholar
Gordon, F. J. 1977b. The effect of protein content on the response of lactating cows to level of concentrate feeding. Anim. Prod. 25: 181–191.Google Scholar
Gordon, F. J. 1979. The effect of protein content of the supplement for dairy cows with access ad libitum to high digestibility, wilted grass silage. Anim. Prod. 28: 183–189.CrossRefGoogle Scholar
Ling, E. R. 1963. A Text Book of Dairy Chemistry, Vol. 2, 4th ed. Chapman and Hall, London.Google Scholar
McIntyre, K. H. 1970. The effects of increased nitrogen intakes on plasma urea nitrogen and rumen ammonia levels in sheep. Aust. J. agric. Res. 21: 501–507.CrossRefGoogle Scholar
McMurray, C. H., Logan, E. F., McParland, P. J., McRory, F. J. and O'neill, D. G. 1978. Sequential changes in some blood components in the normal neonatal calf. Br. vet. J. 134: 590–597.CrossRefGoogle ScholarPubMed
Payne, J. M., Rowlands, G. J., Manston, R., Dew, S. M. and Parker, W. H. 1974. A statistical appraisal of the results of the metabolic profile tests on 191 herds in the B.V.A./A.D. A.S. joint exercise in animal health and productivity. Br. vet. J. 130: 34–43.CrossRefGoogle Scholar
Pfander, W. H., Grebing, S. E., Price, C. M., Lewis, O., Asplund, J. M. and Ross, C. V. 1975. Use of plasma urea nitrogen to vary protein allowances of lambs. J. Anim. Sci. 41: 647–653.CrossRefGoogle ScholarPubMed
Preston, R. L., Breuer, L. H. and Pfander, W. H. 1961. Blood urea and rumen ammonia in sheep as affected by level and source of carbohydrate and protein. J. Anim. Sci. 20: 947 (Abstr.).Google Scholar
Treacher, R. J., Little, W., Collis, K. A. and Stark, A. J. 1976. The influence of dietary protein intake on milk production and blood composition of high-yielding dairy cows. J. Dairy Res. 43: 357–369.CrossRefGoogle ScholarPubMed