A recent study completed by the University of Liverpool evaluated the effect of lameness, a common chronic stressor, on the reproductive performance of dairy cattle. A cow’s lameness and follicular phases synchronized with GnRH followed seven days later by prostaglandin (PG) were monitored in 70 dairy cows, all of which were 30 to 80 days postpartum.

Of the 70 cows included in the trial, 15 lame cows did not respond to GnRH. Of the cows that did not show an ovarian response, milk progesterone was lower than healthy cows in the five days prior to the PG dosage. Furthermore, lame cows experience ovulation and a shorter interval from PG to ovulation.

To further explore the effects of lameness on dairy cattle reproductive performance, cows were divided into two subsets. Research findings were reported in the May 2011 issue of Theriogenology.

Subset one (four healthy and 16 lame):



 Luteinizing hormone (LH) pulse frequency was lower in lame non-ovulating cows than healthy cows.


 Lameness did not affect interval from PG to LH.


 Prior to LH surge, estradiol was lower in nonovulating cows and estradiol concentration was positively correlated with LH pulse frequency.


Subset two (13 healthy, 15 lame ovulated, six lame non-ovulated and 11 lame non-responders):



 Lame cows that ovulated had a less intense estrus than healthy cows

 Lame cows began estrus and stood to be mounted earlier than healthy cows.

Following analysis of the collected results, researchers revealed several parameters to explain poor fertility in chronically stressed dairy cows. From 30 to 80 days postpartum there was a graded effect that ranged from 29 percent lame cows with absence of ovarian activity to another 21 percent of lame cows which failed to express estrus or ovulate a low estrogenic follicle. In 50 percent of cows, many reproductive parameters were unaffected by lameness.

Get the abstract.

Source: Dairy Cattle Reproduction Council