Reproduction and Genetics

Information on dairy cow optimal breeding time, estrous cycle, artificial insemination, and calving. Find resources on heat detection, cow gestation, and breeding dairy cows for milk production.

Dairy Cattle Reproductive Management

The reproductive performance of a dairy herd is one of the most important factors in a cattle farm’s profitability. Successful reproductive management has a significant impact on the herd’s overall performance and producers’ net income.

Heifers must have a calf before they can produce milk, older cows must calve at regular intervals to keep producing milk, and calving is vital for dairy herd replacement programs.

To achieve reproductive efficiency, producers need a high proportion of dairy cattle to become pregnant early in the optimum conception period. Use Penn State Extension’s resources on Heat Detection and Timing of Insemination for Cattle to ensure efficient and profitable reproductive performance of your dairy herd.

Dairy Cow Heat Detection, Estrous Cycle, and Artificial Insemination

Depending on the breed, the optimal age for first calving ranges from 20 to 26 months, and calving once a year is usually the goal. After each calving, cows do not come into estrus for some time, on average 60 days. This anestrus period can range significantly, though – from only 17 days to 150 days depending on various factors. A significant goal for producers is to reduce the number of days that a cow is “open” (not pregnant). Open cows equal profit losses for farmers because they can result in long calving intervals.

Learn more about the stages in the 21-day bovine estrous cycle to accurately determine the dairy cow optimum breeding time. Adapt heat-detection techniques for monitoring cows’ reproductive status and identify the best time for artificial insemination. From milk progesterone analysis to activity monitoring systems, our resources are designed to help dairy producers identify cows in heat and increase conception rates.

Find more information on cow artificial insemination, supplementation of progesterone, and predicting pregnancy loss in your dairy cattle.

Cow Gestation and Calving

The cow gestation period is about 283 days, though it varies by breed and by sex of the calf. Monitoring heifers and cows due to calve is vital in decreasing dystocia and improving calf survival rates. Take advantage of Penn State Extension information resources, such as Calving Alert Systems: Know Exactly When Your Cow is Calving.

Available to dairy producers is our video series on parturition and calving best practices and an on-farm workshop on calving management practices.

Dairy Cattle Infertility Issues

Information on dairy cattle infertility is also available in this section. Learn more about how to identify and treat common infertility problems.

Some cattle diseases, such as bovine viral diarrhea, leptospirosis, and trichomoniasis, are associated with reproductive loss, so producers should make sure they vaccinate their cow herd against reproductive diseases. Visit the Dairy Cow Health and Diseases section for more information on keeping your herd healthy.

Dairy Cattle Breeds

Cattle breeding programs are equally important to single herd farmers and to large-scale farming companies.

Improving the commercial production of farm stock starts with selecting the animals from which to breed. Creating herds from cattle with genes for desirable characteristics allow farmers to achieve a heard with good performers and good breeders. These factors should be taken into account when selecting and developing replacement heifers, as well.

The main dairy cattle breeds are Ayrshire, Brown Swiss, Guernsey, Holstein, Jersey, Milking Shorthorn, American Milking Devon, and Red and White Holstein. Producers can use this growth chart for dairy heifers to compare to the breed standard.