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Tools for managing reproductive efficiency in the cowherd

by Kaitlyn Root

Reproductive performance is one of the core drivers of profitability and success in cow/calf operations. With the breeding season starting or underway for many producers across Wyoming, this is often the time of year we think most about fertility and the reproductive efficiency of the cowherd.

However, reproductive performance is impacted by management decisions made throughout the year. Numerous factors including nutritional management, body condition, herd health, environmental stressors, genetics, etc. can impact reproduction. 

Determining
reproductive efficiency

So, how can we evaluate reproductive efficiency to help ensure success during the breeding season?

Assessing reproductive performance each year will allow for identification of any problems which may have occurred, as well as provide an opportunity to plan for the upcoming year and continue to build on the current success of the program.  

Maintaining records of the number of females exposed to artificial insemination (AI), or bulls at the start of the breeding season, dates when bulls were turned in and removed and the number of calves weaned will allow for assessment of reproductive efficiency. Pregnancy detection (palpation, ultrasound or blood test) is an extremely useful tool in assessing reproductive rates, determining pregnancy status, as well as potentially identifying any late bred cows or heifers.

Calculating weaned calf percentage can be a valuable measurement to consider when evaluating reproductive efficiency in the cowherd. Weaned calf percentage is calculated by dividing the number of calves weaned by the number of females exposed.  

While pregnancy rates describe success during the breeding season, weaned calf percentage will allow for evaluation of the number of cows and heifers which were bred, maintained a pregnancy, had live calves and raised calves to weaning. The ultimate goal of cow/calf operations is for every cow to wean a marketable calf each year, therefore, assessment of the full system from breeding through weaning is an important tool. 

Calving distribution can also be a worthwhile measurement to consider. Cows calving late in the calving season wean young, lighter weight calves, resulting in less productivity and profit. These lower-producing cows, however, cost the same to maintain.  

Calves born earlier in the calving season have significant advantages over late calves, with research reporting early calves having heavier weaning weights, heavier carcass weights and greater marbling scores.

In addition, late calving heifers and cows are at an increased risk of falling out of the herd during the next breeding season.  

Environment impacts
and considerations

With drought conditions persisting and increasing feed costs, cow productivity, efficiency and profitability are critical to consider. 

Tightening the calving window and shifting the calving distribution towards the first half of the calving season can result in heavier calves at weaning and increase calf crop uniformity, potentially resulting in marketing premiums. Furthermore, research has established heifers calving in the first 21 days of their first calving season have increased longevity in the herd and wean more pounds of calf over their lifetime when compared with heifers calving in the second or third 21-day calving period. 

Estrus synchronization may be a viable option to help shorten the calving season and shift the calving distribution. Utilizing a progestin-based synchronization protocol can help initiate resumption of estrous in cows on the edge of resuming cyclicity. Estrus synchronization can be beneficial in herds utilizing either natural service or AI. 

Having a defined calving season can also allow for more efficient nutritional management. Typically diets or supplementation programs are designed to meet the nutritional demands of different stages of production (i.e., gestation or lactation).  

An extended calving season or the lack of a defined breeding season can result in periods of over- or under-supplementation for a significant portion of the cowherd. This can result in either decreased performance or an inefficient use of feed resources, ultimately impacting profitability. 

In addition, with drought conditions resulting in decreased forage availability, culling later-conceiving, lower-productivity cows may be an effective strategy to help manage limited feed resources and potentially increase profitability.

Utilizing the measurements and tools described above can allow producers to identify issues or areas for improvement, as well as serve as an assessment for management decisions made throughout the year. Decisions such as nutrition or supplementation strategies and herd health protocols can directly influence fertility.  

Creating a proactive plan 

In general, nutrition, more specifically cow body condition, is going to have the biggest impact on reproductive success. Making sure cows are at an adequate body condition prior to calving is crucial for ensuring cows resume cyclicity before the next breeding season. 

It is essential protein and energy requirements are being met throughout the year to maintain body condition and support lactation, calf performance and cow or heifer reproduction. 

Developing a good mineral program and a preventative herd health plan are also important factors to consider. Numerous minerals are tied to both male and female reproductive performance, therefore, ensuring mineral requirements are being met throughout the year can help support reproductive efficiency.

Several diseases and pathogens, such as bovine viral diarrhea, infectious bovine rhinotracheitis, leptospirosis, vibriosis and trichomoniasis can also directly impact reproductive performance causing infertility and abortions. 

Taking a systems approach to reproduction by evaluating all of the factors influencing fertility and reproductive performance not only during the breeding season but throughout the year, will allow for identification of areas to increase efficiency or improve performance. It will also provide an opportunity to create a proactive plan for the upcoming or following year, allowing for increases in efficiency and profitability over time. 

Shelby Rosasco is the University of Wyoming Extension beef specialist and an assistant professor at the University of Wyoming in the Animal Sciences Department. Rosasco can be reached at srosasco@uwyo.edu. 

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