Embryonic death rate is a growing concern for dairy herds


Embryonic death rate is a growing concern for dairy herds

File photo
File photo

Water is an integral element of our dairy industry. The current drought is having enormous adverse effects on livestock welfare and putting a lot of stress placed on farm families.

Milk production has dropped dramatically and the incidence of later foetal death has increased. This will ultimately increase the number of empty cows at the end of this breeding season.

Farmers are now faced with the challenges of managing daily herds where grazed grass was the sole ingredient of the diet to one where grazed grass has to be rationed and dietary supplementation of concentrates and silage is the norm.

Aside from this is the need for water by the cow in a high temperature environment. The demand for water increases dramatically in line with the humidity index.

As herd sizes increased over the past number of years there has been a concurrent upgrade in water supply and size of water troughs on farms. The current heat wave has clearly shown the implications of inadequate water supply on some farms.

Farmers have to now contend with the need to get cows in calf while milk production drops because of either inadequate water supply or reduced nutritional intake. Our scanning records for the past month have revealed a dramatic increase in later embryonic deaths.

Embryo mortality beyond day 34 of gestation is primarily associated with either cows carrying twins or infectious diseases such as Neosporin or BVD.

The current drought has increased the stress load on cows and, with water supply being inadequate on many farms, the animals’ immune systems have been compromised as a consequence. This has resulting in diseases such as Neospora and IBR becoming more active in herds. These diseases will kill foetuses beyond day 34 of gestation. Scanning records reveal that this feature of later foetal death only occurred among cows bred after May 20, which points to drought-related stressors.

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Cows experiencing foetal death beyond date 34 of pregnancy will take up to eight weeks to return to heat naturally.

Breeding programme for spring calving will be finished in three weeks time for most herds. Farmers should identify cows carrying dead pregnancies now by scanning. Your vet can then administer prostaglandin to these cows, which will enable them to go back in calf within two to four days.

What can you do to reduce the adverse effect of this drought? Some farmers are frantically sinking new wells to create a better water supply.

Other measures to consider are placing large water troughs close to the exit area from the milking parlour and allowing cows access to water troughs in other areas of the grazing platform where feasible.

Some farmers with access to rivers have started irrigation systems using sprinklers to increase grass growth. This is not feasible on most farms.

It is difficult watching grass turn brown over large sections of land on sandy soils or shallow soil on upland farms.

Farmers are now faced with second cut silage where grass has headed out prematurely because of heat stress. The feed value of this grass will decrease rapidly if not ensiled now.

Alternatively, farmers are either grazing their second cut silage ground or using zero grazing to feed directly to their cows.

In conclusion, the current drought has caused many farmers to reconsider the direction they are taking on expansion.

I believe we cannot continue to run our dairy sector in the ‘red zone’ in terms of stocking rates and milk yields. This year and last year have starkly illustrated the limitations and shortcomings of hard core grass-based milk production systems.

Dr Dan Ryan is a bovine reproductive physiologist and can be contacted at www.reprodoc.ie

Indo Farming

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