Infrequent Milk Progesterone Measurements in Daughters Enable Bull Selection for Cow Fertility

Milk progesterone measures to improve genomic selection for fertility in dairy cows

Environmental effects on progesterone profile measures of dairy cow fertility.

Environmental effects on fertility measures early in lactation, such as the interval from calving to first luteal activity (CLA), proportion of samples with luteal activity during the first 60 days after calving (PLA) and interval to first ovulatory oestrus (OOE) were studied. In addition, traditional measurements of fertility, such as pregnancy to first insemination, number of inseminations pe...

Fertility of Bull Semen Frozen in Skim Milk Diluent

In Victoria the usual diluent for deep frozen bull semen consists of a mixture of egg yolk, sodium citrate and glycerol. The semen is equilibrated in this mixture for 17 hours prior to freezing. O’Dell and Almquist (1957), and Amman and Almquist (1957) found that survival of spermatozoa as assessed by motility was increased when the semen was diluted with a mixture of glycerol, fructose and ski...

Index for daughters’ fertility in the Netherlands

In the Netherlands a fertility index is introducing which describes the fertility of daughters of a bull. The index is based on two breeding values which are estimated for all bulls; non return after 56 days (NR56) and interval between calving and first insemination (ICI). These two traits are combined in an index: the calving interval index or CI-index. This index was developed after comparing...

Bull management for cow/calf producers

Fertility in a bull is generally defined as the ability to impregnate females. Certainly that is a minimum requirement, but a bull with high fertility is able to impregnate more than the expected number of cows in a short breeding season. Such a bull has greater economic value than one of lesser fertility (1,17). If the bull also has a desirable genetic background, it could contribute more than...