Predicting stage 2 of calving in Holstein-Friesian heifers

Association between growth rates, age at first calving and subsequent fertility, milk production and survival in Holstein-Friesian heifers

Age at first calving (AFC) affects the profitability of dairy enterprises. This study examined the relationships between AFC and subsequent fertility, milk production and survival up to third calving in UK Holstein-Friesian heifers; Study 1 comprised 134 consecutively born heifers from the same herd (AFC 764 ± 8 days) and Study 2 contained 445 heifers born on 17 farms (AFC 796 ± 6 days). Growth...

Insemination factors affecting the conception rate in seasonal calving Holstein-Friesian cows.

Differences in conception rate to first service between artificial inseminations (AI) carried out by commercial AI operators (CAI) or do-it-yourself operators (DIY), between natural service (NAT) and AI, between different AI sires, and between fresh and frozen-thawed semen, on Irish commercial dairy farms, were studied using logistic regression. The study comprised 12,933 potential first insemi...

Heterogeneity of genetic parameters for calving difficulty in Holstein heifers in Ireland.

Calving difficulty is a trait that greatly affects animal welfare, herd profitability, and the amount of labor required by cattle farmers. It is influenced by direct and maternal genetic components. Selection and breeding strategies can optimize the accuracy of genetic evaluations and correctly emphasize calving difficulty in multiple-trait indices provided there are accurate estimates of genet...

Inductions of superovulation using several FSH regimens in Holstein-Friesian heifers.

Note Eighty-three Holstein-Friesian virgin heifers were randomly divided into four groups and superovulated with one of the four FSH regimens as follows : Group I) twice daily injections of a constant dose of 5 mg of FSH for a period of 4 days, giving a total dose of 40 mg in 8 fractions ; Group II) as in Group I with additional 5 mg of FSH on the 5th day, giving a total dose of 45 mg ; Group I...

Relationship between serum total cholesterol levels before calving and occurrence rate of diseases after calving in Holstein heifers and cows.