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♦ Why Am I Not Finding Cows In Heat?
♦ Why Am I Not Finding Cows In Heat?

Why Am I Not Finding Cows In Heat?

By: Bob Saar, National Accounts Senior Specialist, Genex

One thing I often hear while working with Genex member and customer herds throughout the Northeast is “my cows are not showing heat and conceiving the way they should.” Let’s take a closer look at the issue and address factors affecting animals’ ability to show heat. First of all, one must determine if the problem exists throughout the entire herd or within a specific subgroup. To do this, analyze the dairy’s computer record system. Specifically, analyze the records for reproduction and events that have happened by lactation or lactation group. Once the group in which the problem exists is determined, one will be better able to find possible causes and solutions, such as the following.

How does flooring affect cows showing heat?

Slippery floors can be a deterrent to cows exhibiting heats and can also cause injury to animals. Generally concrete is the most common flooring surface in dairy facilities. To make concrete flooring more cow-friendly, one could groove or scabble slippery floors. Caution must be used when using grooving or scabbling floor options, as not to make the surfaces too abrasive on hooves. Another option is to use grooved rubber belting or similar rubber products.

How does lameness affect cows showing heat?

Lameness causes stress on an animal. Lameness also tends to cause animals to lie down more and eat less. Obviously, if an animal lies down more, it becomes more difficult to observe signs of heat. And, if an animal eats less, lameness can cause a cow to lose body condition.


 How does body condition loss affect cows showing heat?
It is a known fact in the industry that a one point loss in body condition can inhibit an animal’s ability to exhibit heat. Keeping rations adequate to prevent body condition loss are critical. An old saying I have heard and believe has a lot of merit in this situation: “rations need to be balanced adequately to maintain production and reproduction.” Remember a cow is a mother; she needs enough energy to produce milk (feed her calf) before she will want to reproduce again.

How does the ratio of open to pregnant cows affect cows showing heat?
The higher the number of pregnant cows in a pen the lower the amount of estrus that is shown; pregnant cows and cows in mid cycle are much less likely to mount cows in or near heat. A possible solution for this issue is to maintain a higher percentage of open cows within the breeding group.

How does transitioning affect cows showing heat?
The more metabolic problems an animal has when freshening, the greater probability of anestrus. According to the article, Effect of Disease on Reproduction in Dairy Cows: a Meta
Analysis, clinical ketosis, dystocia and retained placentas are associated with more days to first service and a lower conception rate at first service (Fourichon, Seegers and Malher, 2002). Overcrowding of transition groups may also lead to more metabolic problems at or after calving. Some recently available data looks at bunk space for overcrowding rather than stall space.


 How does failure of proper observation for estrus affect cows in heat?
Jeffrey S. Stevenson of Kansas State University says, “The greatest limiting factor to successful fertilization is associated with detection of estrus. It is estimated that approximately 50% of heats go undetected on the average dairy farm in the U.S.” (1997). He goes on to state, “There are two important challenges in heat detection. The first is accurately recognizing signs of heat and the second is catching all possible heats in breeding heifers and cows. One might be quite accurate in catching cows in heat, but still have a major heat detection problem because too few heats are observed.” One solution for the issue of failure to properly observe estrus may be to adequately train employees in heat detection technique. In regards to specific timeframes for observing animals for heat, the proper time to observe animals is not while they are eating; instead, for the best results, it should be every employee’s job to make sure they observe animals at all times and properly identify the animals in heat. If herds are housed in stanchion barns, they need to be turned out daily, to conduct proper heat detection.

How does heat stress affect cows in heat?
As M.A. Varner of the University of Maryland explains, “The term ‘heat stress’ refers to the stress of hot weather and not the estrous or heat cycle.” He goes on to share how reproductive efficiency is affected by heat stress. “First, cows are harder to detect in estrus and are sometimes classified as anestrus. Second, cows that are bred by artificial insemination have a hard time becoming or staying pregnant. The second problem shows up as low conception rate or high services per conception.” A solution for heat stress is to have a great heat abatement strategy, which may include sprinklers, fans, tunnel ventilated barns, a source of water close to cows exiting the milking parlor, or multiple water sources for cows on pasture. In conclusion, there are many different factors that could cause a producer to say, “My cows are not showing heat and conceiving the way they should.” To overcome the obstacles, a producer needs to drill down through all layers to find the source of the problem - problems that could relate to the cows not showing heat or people not heat detecting correctly. There are also products available to aid in heat detection – such as tail paint, Kamars®, heat detection systems, heat detection workshops and protocol programs – but I suggest not just putting a Band-Aid on an underlying problem. Work with your local resources (veterinarian, Genex consultant, etc.) to determine the problem and fix it from its source.


Fourichon, C., H. Seegers, and X. Malher. “Effects of Disease on Reproduction in Dairy Cows.”

Theriogenology 53.9 (2002). 1729-59.Stevenson, Jeffrey S. “The question would be are their cows really not showing heat or are we not heat detecting correctly.” 1997.

Varner, M. A. “Stress and Reproduction.” Dairy Integrated Reproductive Management.

Special thanks to Jerry Bertoldo, DMV, Dairy Specialist, Cornell University Cooperative Extension, Genesee County, N.Y.

Posted April 2012