Genetics of heifer reproductive traits in Japanese Black cattle

Abstract

Objective: The objective of this study was to identify environmental factors strongly asso ciated with and to estimate genetic parameters of reproductive traits in Japanese Black heifers. Methods: Data included reproduction records of Japanese Black heifers born between 2004 and 2014. First service nonreturn rate (NRR) to 56 days from first to successful insemination (FS), number of services per conception (IN), age at first calving (AFC) and gestation length were analyzed with the use of the general linear model. Genetic parameters were estimated with the use of the univariate animal model of the residual maximum likelihood. Results: Averages of reproductive traits over eleven years were assessed, and the effects of farm, year, month, artificial insemination technician and interaction of farm×year on the traits were determined. Estimated heritability of FS was very low and that of AFC was higher than that of the other traits. A close genetic relation was observed among NRR, IN, and FS; however, their heritabilities were very low. AFC shows favorable genetic correlation with IN and FS. Conclusion: Low heritabilities of most reproductive traits in Japanese Black heifers are strongly influenced by farm management practices, and that large residual variances make genetic evaluation difficult. Among the reproductive traits, AFC is potentially more useful for genetic improvement of heifer reproductive traits because it has high heritability and favorable genetic correlations with IN and FS.

MOET Efficiency in a Spanish Herd of Japanese Black Heifers and Analysis of Environmental and Metabolic Determinants

“…The data from this herd provide an important extension to the literature, much of which centers on herds in Japan. Reproductive traits of Japanese Black heifers are strongly influenced by farm management practices and the farm environment [ 40 ], which can differ substantially between Japanese and Spanish farms. Japanese traditional management is intensive and emphasizes limiting animal movement, even in reproductive herds [ 26 ], in order to optimize fat infiltration and meat quality [ 33 ].…”

Effects of feeding high volumes of milk replacer on reproductive performance and on concentrations of metabolites and hormones in blood of Japanese black heifer calves

“…The average age and the range of ages at calving were 22.1 ± 0.7 months (LSM ± SE) and 19.5–25.2 months, respectively, for cattle meeting the AI physique criteria at 300 days. In contrast, Setiaji and Oikawa (2020) reported that the average and range of age at calving were 25.8 ± 5.4 months (mean ± SD) and 19.7–43.3 months, respectively, for Japanese black heifers. Birth weight was normal in offspring born to dams meeting the AI physique criteria at 300 days of age (31.1 ± 2.2, 29.8 ± 2.3, and 31.8 ± 2.4 kg for the 9 L × 60 days, 9 L × 41 days, and 7 L × 40 days groups respectively).…”

Bayesian estimates of genetic parameters of non-return rate and success in first insemination in Japanese Black cattle

“…Black cows [23] and in Japanese Black heifers [24]. Based on this result, NRR and SFI could be used for early indicator for evaluate the capacity of cows to conceive.…”