Battling the Summertime Repro Slump

Published on Wed, 07/17/2019 - 4:33pm

 Battling the Summertime Repro Slump.

 Some Tips to Limit the Effects of Hot Weather on your Herd's Fertility.

 Article courtesy of Parnell

As temperatures heat up around the country, we can expect to see a slump in fertility rates on cattle operations. Heat stress negatively affects your heifer and cow fertility by increasing days open, minimizing estrus detection, and cause embryonic abortion. Though you may think that the effects only last during the summer, without proper mitigation, it could take months before your fertility rates return to normal levels.
However, there are some things you can do on your farm to better mitigate the effects of the season and keep your pregnancy rate from hitting those terrible lows.

Utilize a Fertility Protocol
In optimal weather conditions, standing heat only lasts between 15 to 18 hours. Hot weather suppresses the expression of estrus in cattle, further shortening your window for heat detection. Therefore, if your farm is primarily breeding to heat, you may experience a decrease in your insemination rate. Subsequently, other fertility rates will be impacted.
Being fully compliant with your selected fertility protocol for timed AI can help mitigate low summer pregnancy rates. It has been shown that utilizing fertility protocols, at least in the first insemination after calving, increased the herd's pregnancy rate compared to
cows bred to heat detection during high temperatures. Eliminating the reliance on heat detection is the primary attribution for improving pregnancy rates. Make sure that your fertility team understands your protocols and knows when each hormone should be administered to see the best results on your farm.

Keep Cows Cool
Pregnant cows are most prone to pregnancy loss due to heat stress within the first days of embryonic development. Cows do not efficiently sweat and depend primarily on panting to regulate internal temperature. Therefore, proper cooling equipment should be implemented to help cows effectively dissipate body heat.
Increasing airflow with fans throughout barns is an easy way to combat high temperatures, and in combination with misters can create evaporative cooling in barns helping regulate the cow's core body temperature. Misters should be used in areas with clean traction flooring and face away from bedding and bunk areas to maintain feed integrity and promote lying time.
If cows are currently on pasture, provide sufficient shade for them to get out of direct sunlight. Aim to place shading in areas that receive breezes to encourage cattle to stand in places with increased airflow.

Embryo Transfer
An alternative method for maintaining pregnancy rates during the summer is embryo transfer. Embryo transfer can benefit genetic advancement on your farm and help bypass the period when cows are most vulnerable to pregnancy loss.
Implanting the embryo when it is less susceptible to heat stress can cause pregnancy rates to remain at levels achieved in cooler months. As stated before, estrus expression is subdued during hot weather, so embryo transfers are most successful when paired with a fertility protocol.
Keep in mind, embryo transfers come at a varying cost. Speak with your veterinarian to further evaluate the benefits and feasibility of implementing the practice on your farm.

Adjust Feed Management
Cattle will reduce their feed intake during hot weather — reduced feed intake affects a cow's overall body condition score, which is a significant factor to successful fertility.
Be sure to review rations with your nutritionist and adjust them to account for decreased intake. Also, try to increase the amount of feed available during the cooler periods of the day. Supplying 60 to 70 percent of a ration between 8 p.m. and 8 a.m. has been shown to prevent decreased feed intake during hot weather months.
Before making any changes to your operation, be sure to evaluate your current practices and facilities. Work with your team to identify which tips you can implement to best help you battle the summertime fertility slump. For more information on cattle fertility visit