- Volume 45 Issue 5
DOI QR Code
Bias and Accuracy of Single Milking Testing Schemes to Estimate Daily Milk
검정일 1회 검정에 의한 착유우의 1일 유량 추정시 오차와 정확도
- Cho, Y.M. (National Livestock Research Institute, R.D.A.) ;
- Ahn, B.S. (National Livestock Research Institute, R.D.A.) ;
- Choi, Y.L. (National Livestock Research Institute, R.D.A.)
- Published : 2003.10.31
This study was conducted to evaluate the adequacy of an alternative a.m.-p.m. testing scheme for milk yield in comparison with the official test method based on weighing two milkings within 24 h. A total of 8,309 p.m. milking weights and 6,767 a.m. milking weights from 72 Holstein cows raised at N.L.R.I. were collected between October 2000 and November 2001. Ratios were computes for daily milk yield to a.m. and p.m. milking weights(direct yield ratios) and ratios of a.m. and p.m. milking weights to daily milk yield (inverse yield ratios). Analysis of variance indicated that the milking interval is the most important source of variation for yield ratios. Adjustment factors for estimating daily milk yield from single milking weights were derived through regression analysis of direct and inverse yield ratios on the length of the milking interval. Daily milk yield was estimated more precisely and accurately when adjustment factors were used than when single milking weights were doubled. In conclusion, alternative recording of a.m. and p.m. milking weights led to reliable estimates of milk yields.
Alternative a.m.-p.m. Daily milk yield;Yield ratio;Adjustment factor
- Cassandro, M., Carnier, P., Gallo, L., Mantovni, R., Contiero, B., Bittante, G. and Jansen, G. B. 1995. Bias and accuracy of single milk testing schemes to estimate daily and lactation milk yield. J. Dairy Sci. 78:2884-2893. https://doi.org/10.3168/jds.S0022-0302(95)76919-3
- Everett, R. W. and Wadell, L. H. 1970. Sources of variation affecting ratio factors for estimating total daily yield from individual milkings. J. Dairy Sci. 53:1430.
- Feddersen, E. 1998. Performance recording of animals, state of the art: Proposal for the update of the pedigree document. Page 291 in Proc. 31st Biennial Session of ICAR, Rotorua, NewZealand.
- Hargrove, G. L. and Gilbert, G. R. 1984. Differencs in morning and evening sampl milkings and adjustment to daily weights and percents. J. Dairy Sci. 67:194.
- Lee, A. J. and Wardrop, J. 1984. Predicting daily milk yield, fat percent, and protein percent from morning or afternoon tests. J. Dairy Sci. 67:351.
- Liu, Z., Reents, R., Reinhardt, F. and Kuwan, K. 2000. Approaches to Estimating Daily Yield from Single Milk Testing Schemes and Use of a.m.-p.m. Records in Test-Day Model Genetic Evaluation in Dairy Cattle. J. Dairy Sci. 83:2672-2682.
- Porzio, G. 1953. A new method of milk recording. Anim. Breed. Abstr. 21:344.
- Putman, D. N. and Gilmore, H. C. 1970. Factors to adjust milk production to a 24-hour basis when milking intervals are unequal. J. Dairy Sci. 53(Suppl. 1):685.
- Rosati, A., Bouloc, N., Claus, J., Mao, I., Schaeffer, L. and Wilmink, H. 1998. Performance recording of animals, State of the art: Report of the Lactation Working Group. Page 249 in Proc. 31st Biennial Session of ICAR, Rotorua, New Zealand.
- SAS. 2000. SAS/STAT User's guide. SAS institute Inc., Cary, NC., USA.
- Smith, J. W. and Pearson. R. E. 1981. Development and evaluation of alternative testing procedures for official records. J. Dairy Sci. 64:466.
- Wiggans, G. W. 1981. Methods to estimate milk and fat yields from a.m./p.m. plans. J. Dairy Sci. 64:1621.
- Wilmink, J. B. M., Galesloot, P., Johnson, D., Ouweltjes, W., Rosati, A., Schaeffer, L. R., Steine, T. and VanRaden, P. 1998. Performance recording of animals, State of the art: Final report of the ICAR-INTERBULL Working Group on Milk Recording Accuracy and its impact on genetic evaluations. Page 249 in Proc. 31st Biennial Session of ICAR, Rotorua, New Zealand.