Environmental effects on the reproductive traits of Korean Native cattle and Charolais crossbreds on farm feeding.
1989
Na K.J. | Hong S.G. | Kim H.S. | Lee K.S.
This experiment was carried out to develop the synthetic breed (5/8 Charolais 3/8 Korean native cattle) with the importation of Charolais (C) traits to Korean Native cattle (K.N.C). The environmental effects on the reproductive traits of K.N.C. and Charolais crossbreds on farm feeding from 1979 to 1985 were estimated by least squares method. The age and standard error at the first artificial insemination (A.I.) was 463.1+-12.4 days in first cross-breed (F1), 489.6+-15.9 days in back cross breed (B1) and the age at the first calving of F1 and B1 was 837.8+-34.4 days, 819.2+-43.2 days, respectively. Age at first A.I. and calving were not significantly different among breeds but were significantly different among sires. The number of A.I. services per conception was 1.382+-0.03 in K.N.C, 1.639+-0.03 in F1 and 1.497+-0.11 in B1. More A.I. services per conception were needed for Charolais crossbreds than those of K.N.C. The average gestation length of K.N.C, F1 and B1 was 287.3+-0.15 days, 286+-0.21 days, and 286.1+-0.78 days, respectively. Gestation length was significantly different among breeds, calving seasons, and sex of calf. The day of A.I. services after calving was 96.2 days in K.N.C, 124.3 days in F1 and 103.5 days in B1. The day of A.I. services after calving of Charolais crossbreds was a little bit longer than that of K.N.C. Calving interval was 401.3 days in K.N.C, 441.3 days in F1 and 392.1 days in B1.
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