Heat Stress?

With warm weather fast becoming the norm in the UK it is paramount farmers consider the effects this hot weather is having on performance. 

What to look out for ?

Once the temperature rises above 24 degrees, especially in humid conditions, signs of heat stress can begin to show in dairy cows including drooling, open mouth breathing, increased respiratory rates, more time spent standing up, reduced rumination, crowding around water troughs, seeking shade and dry matter intakes reduced by 10% or more

What are the consequences?

All these factors can have serious effects on milk production and animal health – including increased clinical mastitis and somatic cell counts, reduced fertility with increased embryo loss and lowered oestrus expression, conception rates and 100 day in-calf rates. Damage to the growing follicles in the cows’ ovaries means that there could also be a 60 day delay before fertility fully recovers.

So what can we do about it?

Some things are relatively easy to implement, such as ensuring ample supplies of fresh drinking water, feeding and milking the cows at cooler times of the day, providing shade by housing the cows by day and grazing the best pastures at night. Other changes need planning further ahead, such as the installation of fans over the feed barriers and the collecting yard. High Volume Low Speed (HVLS) fans first seen in the USA are now beginning to appear on UK farms and can be especially useful when placed over collecting yards.

Do we need to change the cows diets?

An important area not to over look are changes to the nutritional needs of the cows during the risk periods of heat stress. Dairy farmers should seek advice on any necessary changes to the diets, especially for the high yielding cows. With reduced dry matter intakes the energy density of the diet may well need to be increased but with reduced rumination and drooling the supply of saliva to buffer the rumen pH will be reduced so overall there will be a serious risk of sub acute ruminal acidosis. Inclusion of good quality fibre in the diet will help with rumen function but the provision of an effective rumen buffer would be a wise precaution. Increased mineral losses associated with stress and sweating may well need correcting, especially sodium, potassium and magnesium levels.

Does EM have any products to help?

Yes we do. Subacute ruminal acidosis can occur when cows are grazing lush grass rich in soluble carbohydrates and low in fibre and add in the effects of heat stress on rumen function and the inclusion of a buffer in the diet makes good sense. Ostrea is an effective, long acting and cost effective rumen buffer so whenever a TMR diet is fed during the summer 100gms of Ostrea should be included. It is a year round product.

With cows suffering from heat stress likely to have dry matter intakes reduced by 10% or more, another beneficial product to include in the TMR diet is OrganoFresh. It will help prevent the diet from heating up at the feed barrier preventing spoilage organisms from stealing the energy from the diet and making it less palatable. Farmer experience in Germany is that it will improve intakes by up to 2Kg fresh weight per day worth around 2 litres of milk and many farmers their now include the product 365 days of the year. A valuable tool in combating the effects on the cows performance on those hot humid days.

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