GENO Breeding and A.I. Association of Hamar, Norway recently completed a study evaluating behavior associated with standing estrus in lactating dairy cows, in addition to the behavioral changes during a complete estrous cycle. The research was reported in the March 2011 Journal of Dairy Science.

Monitored by video recording, 20 Holsteins were evaluated during one 22-day estrous cycle. Both primary and secondary signs of estrus were recorded and ovarian cyclicity was confirmed by measuring progesterone levels. Standing to be mounted was considered the primary sign of estrus, while anogenital sniff, chin rest and mounting were considered secondary signs.

Researchers reported the following observations:

13 cows exhibiting estrus-like behavior had short standing and mounting periods.

During standing estrus, cows displayed a variety of behaviors both received and initiated.

Frequency of secondary signs increased gradually within the last 12 hours before standing estrus, with greater frequency between four to six and one to three hours prior to standing estrus.

Primary and secondary signs of estrus decreased three hours following standing estrus.

Researchers concluded that chase up can be regarded as a reliable indicator of estrus. They also found changes in initiated and received behavior can distinguish between the different stages of estrus. Knowledge of these behavioral signs may increase heat detection rates and better predict optimal breeding times.

Source: Dairy Cattle Reproduction Council