Estimation of milk consumption curve parameters for different genetic groups of bovine calves
| Autor: | E. L. Villarreal, C. A. Mezzadra, R. Paciaroni, S. Vulich, L. M. Melucci |
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| Rok vydání: | 1989 |
| Předmět: | |
| Zdroj: | Animal Science. 49:83-87 |
| ISSN: | 1748-748X 1357-7298 |
| DOI: | 10.1017/s000335610000427x |
| Popis: | Milk consumption was estimated for crossbred suckled calves from birth to weaning during 2 years. Breed groups utilized were Aberdeen Angus (A) and Charolais (C) sires on Fl Angus-Hereford (and their reciprocals) dams in the 1st year and in the 2nd year, sires A and Nelore (Bos indicus) (N) were used on the same type of dam. The weigh-suckle-weigh technique was employed twice a day to estimate milk consumption on a weekly basis. Estimations were adjusted by least-squares for the effects of genetic group, week of estimation, and their interaction, with sex of calf and calf and cow weights in the week of estimation as covariables. Then a non-lineal regression equation of the form: y = b0Wb1e -b2b2W was fitted for each individual, where y = milk consumption and W = week of estimation. Curves for A and C were very close in their shape, but with a greater consumption (P < 0·01) for C. For the 2nd year, there were differences among A and N both in the shape of the curve and in consumption at the peak of lactation (P < 0·01). Differences in time to peak lactation were also found: for A calves, it was week 9, for C calves week 10 and for N calves week 3·8. The N group showed a sharper decline in persistency than the other groups, suggesting different patterns in milk consumption. |
| Databáze: | OpenAIRE |
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