Why the recent heatwave has increased the risk of embryo loss in cows
The weather in June brought the challenges of both a heatwave and some heavy rain.
The wet spell delayed silage harvesting by two weeks on many farms. This will have an adverse knock-on effect on the DMD of silages fed during the dry cow and fresh cow transition periods next winter.
It will be important to carry out silage sampling next autumn. This will ensure that correct dietary supplementation occurs in the winter months.
The heatwave highlighted the demand cows have for water. As herd size increases and cows travel further on the grazing platform, there is an exponential increase in demand for water.
Larger rapid-fill tanks are required to pump water to a network of feed stations on the grazing platform.
Water deprivation not alone reduces milk production, it also increases the risk of embryonic mortality.
Cows that have lost an embryo will not return to heat before the end of the breeding season. The signal for pregnancy maintenance emanates from the trophoblast, which envelops the developing embryo. This trophoblast ultimately is described as the afterbirth seen when the cow calves.
The trophoblast continues to produce the signalling factor for pregnancy maintenance up to six weeks after an embryonic death. Blood and milk tests for pregnancy will give false positive results where embryonic death maintains a pregnancy status in cows.