Reproductive Behavior

Live cover breeding in dairy cattle is rare, but when it is used it is important to know what behaviors to look for when getting ready to breed.

Females In Estrus

Behaviors of cows in are important to keep track of because certain behaviors can indicate when she is in estrus and ready to be bred. Cows will exhibit a "standing heat", meaning they allow other cows to mount them, mounting other cows themselves, and an increase in locomotive activity when they are in estrus (1). Standing heat is also known as lordosis, where the cow will arch her back and brace her hind legs to be mounted. Because females are only receptive to breeding when in estrus, they are typically the ones initiating copulation or allowing themselves to be bred during season. This is referred to as proceptivity. These pre-copulatory behaviors allow producers to know when is the best time to breed them. Receptivity is important during the copulation phase because this ensures that the bull is able to breed the cow successfully.

The memory portion of postcopulatory behavior is important because that can determine the success of future breedings of the cow. If the cow has bad experiences with a bull during natural breeding, it could make her more reluctant to allow breeding in the future. Luckily, this problem is eliminated greatly by the use of AI.

Figure 9. Table demonstrating the differences in the three stages of reproductive behavior between males and females

Figure 10. Video demonstrating reproductive behavior between Dexter cattle. Although this video doesn't show any successful breeding, there are a lot of examples of the courtship behavior between the cows and the bull.

1:50 - female mounting showing estrus

1:54, 2:20 - flehmen response from male

2:14 - sniffing vulva

Male Reproductive Behavior

Precopulatory Behavior

Attractivity behaviors from the cow will signal a bull that she is receptive to breeding. The bull will rest his chin on the back of the cow to see if she exhibits lordosis. This will lead to courtship behaviors from the male like sniffing the vulva and a flehmen response. The flehmen response creates a decrease in pressure in the nasal cavity, which forces air through the vomeronasal organ and improves the bulls ability to smell the pheromones from the cow. Once he finds that the cow is receptive, the bull will become sexually stimulated and erection and protrusion of the penis will occur.

Copulatory Behavior

When the bull is sufficiently stimulated, he will mount the cow and begin copulation. Because bulls are short copulators, this process only takes 1 to 2 minutes. After intromission, the glans penis is stimulated within the vagina and ejaculation will occur.

Postcopulatory Behavior

The refractory period in the bull is the time when a second copulation will not take place. This period can vary due to the age of the bull, the amount of sexual rest before copulation, and the novelty of the female. It's important in bulls that are used for semen collection to reduce the refractory period so the most samples can be collected as possible. This can be done by exposing the bull to a new female or a new place for collection, which is known as the Coolidge effect.

Memory is important for bulls for the same reason as it is for cows. If the bull has a positive experience when breeding, they will continue to be successful breeders. If they are injured or have negative experiences, this can affect the bulls future as a sire.

Gaude, I., Kempf, A., Strüve, K. D., & Hoedemaker, M. (2021). Estrus signs in Holstein Friesian dairy cows and their reliability for ovulation detection in the context of visual estrus detection. Livestock Science, 245, 104449. https://doi.org/10.1016/j.livsci.2021.104449

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