The impact of hot weather on fertility
Each phase of a cow’s life requires a different health approach. A subject that sometimes gets less attention is fertility, while this is often the second reason for culling on a dairy farm. A changing environment, especially at higher temperatures, can influence the cow’s fertility level. You can read how this works in this article.

Less active due to heat
At higher temperatures, cows are unable to release their heat. The ruminating process costs energy and generates heat, so cows eat less during this period. At warm body temperatures, the cow is more concerned with maintaining a normal body temperature. Due to the heat, cows are less active, which has a direct effect on the visibility of the cow’s heat. The warmth means that cows do not jump on each other as much as usual, which makes it more difficult for the dairy farmer to detect heat in this period. Because milk production and resistance are more important for the animal, the energy will be distributed to these processes. Decreased intake reduces energy, and the reproductive system will be the first to receive less energy.
Three weeks before insemination already a danger
The ovum develops in the period before the heat. If the cow has a high body temperature during this period, there is a chance that the egg cell is of lower quality. This reduces the chance of fertilisation. Oocyte starts to mature as early as 85 days before ovulation. Therefore, ova are of a higher quality at the beginning of lactation. This results in an increased chance around day 56. The next heat is to start developing the follicle after calving. Hot conditions starting from 85 days before insemination can already have a negative effect. If fertilisation is successful, the embryo has difficulty coping with an excessively high body temperature, resulting in more early embryonic death.
Energy plays an important role in good fertility
If the average number of days in lactation of the cow is lower, milk production will be more efficient, according to Geert Opsomer of UGent. In the ideal picture, he talks about a herd that averages 160-180 days in lactation. When your herd averages more than 200 days of lactation, production efficiency drops. A cow is fertile every three weeks; insemination between day 30 and 50 uses the highest quality egg. Due to warmer temperatures and lower feed intake, cows are less able to maintain milk production and will use more fat reserves. As a result, after the peak, the milk production will drop faster. The long-term consequence of this is that cows will become fat when they begin to dry.
Less active due to heat
The roughage intake of a cow decreases during warmer periods, in order not to overheat. Reduced feed intake and increased respiration during warm periods reduce ruminal activity, resulting in lower saliva production and lower availability of the buffering bicarbonate. Cows already naturally produce bicarbonate and through their saliva keep the acidity (pH) of the rumen as stable as possible. Through rumination, a cow produces 2 kg of bicarbonate in its saliva every day. Therefore, ruminative activity is essential for supporting the animal throughout the entire period. If more acid is formed in the rumen than can be absorbed through the rumen wall, discomfort may occur. Highly productive animals can suffer from this in particular. The AHV Booster Tablet ensures that the rumen works more efficiently.

When to use AHV Booster for fertility?
In practice, we regularly see challenges in the area of fertility. This often has to do with the available energy for the cow. Think for example of cows that do not show heat. This is often related to the fact that your cow is fighting other challenges or has not absorbed enough energy in the past or present. There is then too little energy available for showing heat. “Today, we give Booster advice based on the data available on the farm. If you see that a cow is falling too fast in milk production or other key figures (e.g. fat/protein content), it is possible to act on it proactively this way. Companies that work with our AHV app see that the energy balance has improved since the cooperation.”
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Would you like to be visited by an advisor to discuss the health challenges on your farm together? Our AHV Specialist will be happy to visit you to jointly assess the health of your cows and come up with appropriate cow-specific advice.
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