지원사업
학술연구/단체지원/교육 등 연구자 활동을 지속하도록 DBpia가 지원하고 있어요.
커뮤니티
연구자들이 자신의 연구와 전문성을 널리 알리고, 새로운 협력의 기회를 만들 수 있는 네트워킹 공간이에요.
논문 기본 정보
- 자료유형
- 학술저널
- 저자정보
- 발행연도
- 2013.1
- 수록면
- 489 - 500 (12page)
이용수
초록· 키워드
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Daily milk yields on test days were estimated using morning or afternoon partial milk yields collected by official agencies and the accuracy of the estimates was determined. Test-day data for milk yields consisted of 3,156,734 records of AM/PM partial milking measurements of 255,437 milking Holstein cows from 3,708 farms collected from December 2008 to April 2013. A linear regression model(LRM) was applied to estimate daily milk yields using alternate AM/PM milk yield records within lactation stages, milking intervals, and parities on every daily milk yield. The alternate statistical approach was a non-linear hierarchical model(NHM) in which Brody’s growth function was implemented by reflecting an animal’s physiological milk production cycle. When compared with LRM, daily milk yields predicted by the NHM were assumed to be functionally related to day in milk(or lactation) stage, milking intervals, and partial milk yields. Since the results were in terms of accuracies based on comparisons of different statistical models, accuracies of estimates of daily milk yields by NHM were close to those determined by the LRM. The average of these accuracies was 0.94 for AM partial milk yields and 0.93 for PM partial milk yields for first calving cows. However, the accuracies of AM/PM milk yield estimations from cows under a calving stage higher than the first parity were 0.96 and 0.95, respectively. Correlations between the estimated daily milk yields and the actual daily milk yields ranged from 0.96~ 0.98. These accuracies were lower for unbalanced AM/PM milking intervals and the first calving cows. Overall, prediction of daily milk yields by NHM would be more appropriate than by LRM due to its flexibility under different milk yield-related circumstances, which provides an idea of the functional relationship between milking intervals and days in milk with daily milk yields from statistical viewpoints.
(Key words : AM/PM milk yields, Prediction of daily milk yields, Milking intervals, Brody’s function, Accuracy)
목차
등록된 정보가 없습니다.
참고문헌 (23)
참고문헌 신청
Barash, H. / 2001 / Interrelationships among ambient temperature, day length, and milk yield in dairy cows under a Mediterranean climate / J. Dairy Sci 84 : 2314 ~ 2320
Brody, S. / 1945 / Bioenergetics and growth / Reinhold Publishing Co
Cassandro, M. / 1995 / Bias and accuracy of single milking testing schemes to estimate daily and lactation milk yield / J. Daily Sci 78 : 2884 ~ 2893
DHIA / / Simplifying DHI test plans. National DHIA, National Dairy Herd Information Association
DeLorenzo, M. H. / 1986 / Factors for estimating daily yield of milk, fat and protein from a single milking for herds milked twice a day / J. Dairy Sci 69 : 2386 ~ 2394
Brody, S. / 1945 / Bioenergetics and growth / Reinhold Publishing Co
Cassandro, M. / 1995 / Bias and accuracy of single milking testing schemes to estimate daily and lactation milk yield / J. Daily Sci 78 : 2884 ~ 2893
DHIA / / Simplifying DHI test plans. National DHIA, National Dairy Herd Information Association
DeLorenzo, M. H. / 1986 / Factors for estimating daily yield of milk, fat and protein from a single milking for herds milked twice a day / J. Dairy Sci 69 : 2386 ~ 2394
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