As temperatures soared across the UK in late May and early June, many farmers will have had cows that experienced heat-induced stress ranging from mild dehydration to heat stroke, but for autumn calvers, the full effect may not be fully realised until calving.
In a press release, Nettex’s technical livestock manager Nia Williams advised farmers that due to the recent heatwave, “cows calving this autumn are at a greater risk of producing calves with impaired immunity.”
Williams advised farmers that these calves may be facing greater risk of scours in the early stages of life.
Heat stress can disrupt a cow’s normal feed intake levels, increase the cow’s susceptibility to infections such as pneumonia, and impact mammary gland development, all of which can impact the cow’s ability to produce colostrum.
Commenting on the effects, Williams noted that:
“Calves born to heat-stressed cows are often lighter at birth, and can show reduced growth rates both before and after weaning.”
Williams advised farmers that colostrum should be feed rapidly after birth and that farmers should monitor the effect of passive antibody transfer with a blood test between 1 to 7 days from birth.
It is a requirement under the Welfare of Farmed Animal (England) Regulations 2007 that all calves receive colostrum within six hours of birth. The quicker the calf receives colostrum, the greater the absorption of antibodies (immunoglobulins) and stronger the calf’s immune system.
Calves suffering from heat stress may exhibit symptoms including poor suckling, low energy and open-mouth breathing. Nutritional support may be needed.
Electrolytes are commonly used on farm and are easy to use, cost effective, and show rapid improvements in calf health especially where calves are scouring. If symptoms do not reduce or disappear, veterinary assistance may be required.
Cow health
Autumn calvers will be at particular risk of heat-induced stress. Water consumption and appetite reduce significantly in the lead-up to calving resulting in dehydration and in many cases mineral deficiencies.
Calcium deficiency or milk fever is the most common but other subclinical deficiencies can develop such as zinc, selenium, and copper.
“During calving, cows can lose close to 60L of water through blood and uterine fluids, along with significant electrolyte losses.”
Williams advises farmers to support cows immediately after calving with nutritional support. The feeding of minerals, electrolytes, and vitamin-dense products in solid or liquid form is increasingly common.
Boluses are also increasingly popular post-calving as well as mineral injections (where deficiency is identified) as an insurance policy that mitigates the risk of developing clinical or subclinical deficiencies post-calving.