Noble Research InstituteI think of reproductive efficiency as a puzzle, reaching the most efficient means to optimize pregnancy rates within a single breeding season.

Walker ryon
Ryon S. Walker
Livestock Consultant / Noble Research Institute

This includes increasing pregnancy rates, reducing breeding cost, shortening the calving season, more efficient use of labor and matching a breeding program with facility and pasture resources.

Within each piece of the puzzle, many producers have figured out hidden secrets unique to their operations. As a consultant, I get to work with thought-provoking producers and am constantly learning about their secrets to efficiency.

As I work with other producers on breeding management goals, I find myself asking them, “Have you thought about this?” which leads to my five tips to consider for improving reproductive efficiency.

1. Use reproductive technologies to help control your calving season. Natural service, no doubt, is the most successful method of breeding cattle for producers today. However, estrous synchronization and A.I. can be used to improve reproductive efficiency. These systems allow producers to reach certain production or economic goals quicker than natural service and can open the doors to value-added markets as well. Some of the benefits include:

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  • Shortening and concentrating the calving and breeding seasons

  • Increasing the time available for postpartum recovery in cows and first-calf heifers

  • The ability to induce anestrous cows and prepubertal heifers to cycle

  • Introducing new genetics into the herd

  • Improving calf performance and uniformity at weaning (weight, color and disposition)

If the goal is to shorten your calving season, estrous synchronization needs to be considered to facilitate that goal in a shorter timeframe. Estrous synchronization allows the majority of the cows a chance to conceive on the first day of the breeding season. Estrous detection can be a time- and labor-consuming process, making A.I. programs impractical for some beef producers. Estrous synchronization systems that incorporate timed A.I. have advanced in their ability to control the estrous cycle and induce ovulation at a predetermined time, which eliminates the need for estrous detection.

2.  Consider not using A.I. in your thinner cows. Body condition at calving can have an impact on the length of your breeding season. Cows must calve in good body condition (body condition score of 5 or 6) in order to reduce the postpartum recovery period and increase the percentage of cows cycling prior to the breeding season.

However, if some cows are in less-than-ideal condition (less than 5 body condition score) at breeding, and you utilize A.I. in your breeding program, I would consider synchronizing and letting the bull breed them. Numerous studies have shown pregnancy rates to A.I. are lower in thinner cows.

So why risk the semen cost on higher-risk cows? Some estrous synchronization protocols (progesterone-based) can induce anestrous cows to cycle, bull presence can stimulate the pheromone response that initiates cyclicity, and the bull will do a better job than the A.I. technician.

3.  Manage lactating 2-year-olds and later-calving cows differently. Estrous synchronization programs can be used for natural-service breeding to concentrate the calving season further without the use of A.I. I am a big proponent of A.I., but I do believe A.I. is not always the best option.

Using an estrous synchronization program with natural service is another tool that can increase the chances of getting those females bred during their first estrous cycle, particularly for first-calf heifers and late-calving cows. First-calf heifers require more time to return to first estrus after calving than mature cows.

Nutrient requirements are much higher for the postpartum recovery process, lactation, maintenance and growth. Late-calving cows will oftentimes fall later into the calving season, year after year, until they end up open. How quickly this occurs depends on the length of the breeding season.

Identify cows that have calved within the last 30 to 45 days of the calving season and synchronize them with a progesterone source. The progesterone source will help prime their reproductive system and allow the opportunity to kick-start them to cycle early on during the breeding season.

Note: Bulls should be turned out on the last day of the synchronization protocol at a ratio of one bull to 20 cows for the first 21 days.

4.  Determine which cows are still cycling at the end of the breeding season. Strategic culling of late-calving and open cows will assist in shortening the breeding and calving seasons. This will require pregnancy determination at some point during weaning. Depending on the stage of pregnancy at determination, it can be difficult to accurately determine days pregnant (or when the cow will calve during the calving season).

Knowing when cows will calve allows you to make strategic decisions for determining calving groups and culling. Using estrous detection aids (paint sticks, estrous detection patches or heat mount detectors) toward the end of your breeding season, or when bulls are pulled, will allow you to identify cows still cycling and will allow you to make decisions early.

If cows do not respond and are not cycling, that gives you an indication they are not open and will allow you to manage those females for a tighter calving season. Tree cover within a pasture will have an impact on activating these aids, so you should use these aids in pastures with little to no tree cover. Note: It is still recommended you have the pregnancy status confirmed in your herd during weaning.

5.  Replacement heifers that conceive early stay longer. Consider keeping only the bred heifers that conceive early in the breeding season. Research suggests heifers that conceive early during their first breeding season have a higher likelihood of staying in the herd longer.

A replacement heifer represents a producer’s most costly improvement in their herd genetics, so longevity is an important trait to select for. This may require you to develop more heifers each year to meet a defined replacement goal, but the heifers that conceive later can be marketed as bred heifers and have a higher market value compared to a feeder calf.

There is no set number of factors that contribute to reproductive efficiency, and factors may be slightly different from producer to producer. We know the benefits to some of the common tools used to improve fertility; however, sometimes it’s the tactics of how we use these tools that improve our efficiency.  end mark

PHOTO: Knowing when cows will calve allows you to make strategic decisions for determining calving groups and culling. Photo courtesy of Noble Institute.

Ryon S. Walker