During the summer months, dairy cows are highly susceptible to heat stress, resulting in significant reduction in performance, an increased incidence of diseases, and, in severe cases, mortality — ultimately reducing farm profitability.
To address this challenge, dairy farmers and nutritionists are encouraged to plan and implement heat abatement strategies that minimise the negative impact of heat stress on dairy cows’ health and performance.
While this article does not aim to provide a comprehensive discussion on heat stress, it will highlight practical strategies that can be implemented on-farm to minimise its effects, with an emphasis on nutritional tools such as the supplementation of B vitamins.
The negative effects of heat stress on dairy cows are well-documented in journals and industry publications, and include a reduction in feed intake, milk yield and milk composition; lower reproductive performance and immune response; and increased risk of diseases such as mastitis, acidosis and ketosis.
Milk production can quickly decline following exposure of dairy cows to heat stress, with about a 10 per cent drop within two to three days, and about a 25 per cent drop after six days of exposure.
Several practical strategies can be implemented on-farm to mitigate the effects of heat stress, including:
- Providing shelter or shade to reduce radiant heat.
- Installing sprinkler and fan systems to help the cows with evaporative cooling.
- Increasing fermentable fibre in the diet.
- Increasing the energy density of the diet using slowly fermenting starch sources, such as maize, and considering bypass fat.
- Ensuring an adequate provision of cool, clean drinking water.
- Feeding cows during the cooler times of the day.
- Using additives such as rumen-protected B vitamins to reduce stress and improve metabolic efficiency.
B vitamin supplements
Vitamins of the B complex are co-factors/co-enzymes that facilitate various metabolic processes in the animal, including glucose synthesis, fat and protein synthesis, and immune function.
Research has shown that supplementation of rumen-protected B-vitamin blend may improve the energetic efficiency of dairy cows, thereby reducing the negative effects of heat stress (Sacadura et al., 2008).
A study conducted during the summer in northern Mexico also showed improved reproductive performance when the ration of dairy cows was supplemented with a blend of protected B vitamins during the lactation period compared to cows that were not supplemented.
Also, research has shown that any nutrient or compound that improves metabolic efficiency will help to reduce the negative impact of stress-related inflammatory responses.
Heat stress is detrimental to dairy cows’ health and performance.
Implementing proactive actions to mitigate its effects is essential to maintain cow performance and farm profitability.
Management and nutritional strategies, such as supplementing rumen-protected B vitamins, can improve metabolic efficiency and reduce the negative impact of heat stress.
Jefo Nutrition manufactures rumen-protected B-vitamin blends designed to support dairy cows during both the transition and lactation periods.
The Jefo Ruminant Technical Team will be at International Dairy Week, and can provide more information on how Jefo’s solutions can help mitigate the effects of heat stress.
By Dr Razaq Balogun, Jefo Australia’s ruminant technical sales manager.