Ensure Heifers Thrive During Cold Weather

When it comes to the weather and dairy animals, we often think of heat stress in the summer. However, dairy cattle, especially younger dairy animals, can be affected by cold stress, too. This article will focus on dairy heifers between post-weaning and calving age. Dairy farmers should assess their heifer management to ensure this age group of replacement animals can grow well in cold weather, and steps should be taken to prevent cold stress and minimize health issues.

Lactating cows are fairly tolerant to cold temperatures. Lactating and dry cows with a heavy winter coat can withstand temperatures below 18˚F before feeling any cold stress (Wagner, 1988). However, young post-weaned heifers can experience cold stress when temperatures fall below 32˚F (Eastridge, 2019). While older breeding and calving age heifers can be more adept to cold, they still need proper care to protect them from winter weather.

A dairy animal's normal body temperature is 101°F. Cold stress in dairy cattle happens when the animal's body temperature drops. During cold stress, a heifer's body must work to maintain its core temperature, resulting in that energy being diverted away from its other systems responsible for growth and development. Normally, a heifer's winter coat, plus their natural metabolic processes, like rumination, can keep them warm. During extremely cold temperatures, especially if there is inadequate housing, lack of dry bedding, insufficient nutrition, or a combination of these, heifers may experience cold stress.

Housing and Bedding

Because of this increased demand for energy, dairy heifer housing is critical during the winter. Dry, well-bedded pens make a significant difference in a heifer's ability to tolerate cold stress. Adequate bedding should be provided. Often, the pre-weaned calves and lactating herd receive proper bedding, while the post-weaned to calving age heifers may not receive the proper bedding amounts in their pens to keep their coats dry. There are many bedding options for heifer housing, such as straw, shavings, and corn fodder. The bedding should be clean, dry, and absorbent to help the animals preserve body heat.

One way to test the dryness of heifer pens is the knee test. To do this, try dropping to your knees in several areas around the pen. If your knees are still clean and dry after 10–15 seconds of kneeling on the bedding, then the bedding is sufficient. But if your pants are dirty or damp, more fresh bedding should be added.

Keeping heifers dry during the winter can be challenging, but wet coats have reduced insulation properties. The hair coat’s natural insulating property is reduced when the coat is covered in mud (Tarr, 2022). These animals with wet coats or excess manure and mud may be at risk for increased heat loss (CIRG Report, 2004). When observing the animals, if the majority of a group has excessive mud-caked coats, extra bedding needs to be added. Pens may need to be cleaned more frequently to ensure heifers have access to dry bedding.

Heifer housing should also allow for adequate air exchange without becoming drafty. The housing should protect the heifers from the environmental extremes. According to the US National Animal Health Monitoring Survey, bovine respiratory disease (BVD) is the most recorded health problem in weaned heifers (Overton, 2020). Respiratory problems tend to increase in calves and heifers when housing doesn’t offer sufficient air exchange. In Overton’s study, it was found that the economic impact of raising a heifer with (BVD) costs an additional $252 per case. Additionally, heifers with BVD tend to have a slower growth rate, leading to a delay in first service and an average age of older at first calving (Overton, 2020).

It's important to monitor the heifers' breathing and take notice of any animals coughing. If heifers have respiratory issues, consider taking steps to improve airflow. For example, barns can be fitted with tube ventilation to help increase airflow.

Heifers housed outdoors need to have access to either natural or constructed windbreaks. Wind significantly reduces the actual temperature, increasing cold stress on heifers.

Nutrition

To prevent cold stress, the animal will increase its metabolic rate and use energy reserves to supply more body heat (Johnson, 2019). On the nutrition side, adequate nutrition is important during colder weather to help heifers reach their full growth potential. This growth is necessary so that heifers achieve the correct breeding size. To do this, heifers need to average around 1.75 pounds/day of growth for large breeds and 1.3 pounds/day for smaller breeds (Eastridge, 2019). Heifers may experience stunted growth if they are exacerbating their energy reserves to maintain body temperature due to poor nutrition or housing.

Data has shown that undersized heifers may calve later than the desired age range of 22 to 24 months. These smaller heifers tend to be more prone to calving problems and less productive (Heinrichs, 2022). Farmers should work with their nutritionist to make sure that their heifers have enough energy in their diet to help protect them from the cold weather and to ensure proper growth.

Water

Another critical factor to help heifers during colder temperatures is to always have water available. Frozen waterers or troughs and excessively cold water can limit water intake. Restricting water will negatively affect feed intake and make it more difficult for heifers to meet their energy needs (Tarr, 2022). Dairy heifers between the ages of 5 and 24 months will drink about 3.8 to 9.6 gallons of water per day (Meehan, 2021). Monitoring for frozen waterers is important during the extreme colder temperatures.

It’s important to ensure heifers grow to their genetic potential to reach their full ability as lactating cows. Providing the fundamentals of heifer care, including proper housing and bedding, nutrition, and water will help heifers thrive during cold weather.

References

CIGR Design Recommendations of Beef Cattle Housing. 2004. Report of the CIGR Section II, Working Group No. 14. Cattle Housing 2nd edition.

Eastridge, M. 2019. Managing Dairy Calves and Heifers during the Winter Months. The Ohio State University.

Heinrichs, J., C. Jones. 2022. Monitoring Dairy Heifer Growth. Penn State Extension.

Johnson, K. 2019. Managing dairy cattle in cold weather. University of Minnesota. 

Meehan, M.A., G. Stokka, M. Mostrom. 2021. Livestock Water Requirements. North Dakota State University Extension.  

Overton, M. W. 2020. Economics of respiratory disease in dairy replacement heifers. Animal Health Research Reviews. 21(2):143-148.

Tarr, B., and S. Gain. 2022. Cold Stress in Cows. Ontario Government Factsheet.

Wagner, D. 1988. Effects of Cold Stress on Cattle Performance and Management Factors to Reduce Cold Stress and Improve Performance. Bovine Practitioner (23): 88-93.