Reproductive efficiency is a key driver of profitability in a cow-calf operation, since females that don’t conceive still consume resources without producing a return. Several factors influence pregnancy outcomes, including animal health, nutrition, stress and adherence to estrus synchronization protocols. In this article, we’ll explore 15 key factors you can manage – before, during and after the breeding season – to help maximize pregnancy rates and set your operation up for success.
Before the breeding season
1. Mineral program
Cattle require both macro- and microminerals for optimal health and performance; these requirements vary with age and stage of production. Testing forage is essential to identify mineral deficiencies or toxicities and to develop an appropriate supplementation strategy. Working with a nutritionist can help you create an effective mineral program, and implementing a year-round approach ensures requirements are being met at all times, supporting overall herd health and reproductive success.
2. Breeding soundness exam
To help avoid low pregnancy rates to cleanup bulls, herd bulls should undergo a breeding soundness exam approximately 30 to 60 days before they are turned out with females. This allows time to address any issues or to secure a replacement if needed. In addition to the physical exam, monitoring bulls for adequate libido and active mating behavior during the breeding season is essential for reproductive success.
3. Vaccinations
A proper vaccination program is crucial for preventing diseases that impact herd fertility. Research indicates administering modified-live and killed vaccines at least 45 days before artificial insemination minimizes the risk of reduced conception rates. Work with your veterinarian to establish or adjust your vaccination program to best support reproductive success.
4. Body condition score (BCS)
Females in good body condition (BCS of 5 or higher) at artificial insemination, particularly those on an increasing plane of nutrition beforehand, achieve the greatest conception rates. Females in poor body condition focus their nutrient utilization on survival over reproduction, leading to lower pregnancy rates. Body condition at calving also plays a critical role, influencing fertility in the next breeding season. Research shows that females with a body condition score of at least 5 after calving have greater pregnancy rates the following breeding season.
5. Postpartum period
After giving birth, a female’s uterus requires time to recover, and she must resume cyclicity before being able to conceive again. Regular use of estrus synchronization and artificial insemination increases the number of females that conceive at the beginning of the breeding season, leading to a greater proportion of females calving earlier. These early-calving females have more time to resume cyclicity before the next breeding season, which improves their chance of pregnancy success.
During estrus synchronization and artificial insemination
6. Estrus synchronization protocol
Plan your estrus synchronization protocol well in advance to ensure it aligns with your desired artificial insemination date. Use only proven protocols published by the Beef Reproduction Task Force, since they are research-based and updated annually to maximize pregnancy success.
7. Hormone administration
Estrus synchronization relies on three key hormones: GnRH, prostaglandin F2α and progesterone. Each hormone plays a specific role and must be administered on the correct day according to the selected synchronization protocol. Deviating from the prescribed schedule can result in lower estrus expression and pregnancy rates.
8. Hormone storage
Since hormones are the core of any estrus synchronization protocol, proper storage is crucial to ensure their effectiveness. Always follow label specifications for storage and keep them out of direct sunlight during use. Certain hormones require refrigeration, so when using them out in the field, ensure they remain properly cooled to maintain their potency.
9. Needle length
Proper hormone administration requires injecting into the correct tissue for maximal effectiveness. Using the appropriate needle length for the required route of administration ensures accurate hormone placement. For intramuscular injections, a 1.5-inch, 18-gauge needle is recommended, while subcutaneous injections should be given with a 1/2- to 3/4-inch, 16- or 18-gauge needle.
10. Semen quality
Purchasing semen from a reputable source is essential to ensure it has undergone rigorous quality control checks. After purchase, proper storage and semen handling are crucial to maximize pregnancy rates to artificial insemination.
11. Cleanliness
Maintaining cleanliness during estrus synchronization and artificial insemination is necessary to prevent infections that could reduce pregnancy rates. Before insertion, ensure that your controlled internal drug release (CIDR) and CIDR gun are clean. Inserting the CIDR gun with the opening facing downward helps prevent manure contamination if the female relieves herself. At the time of artificial insemination, avoid contact between the top portion of the sheath and A.I. gun with dirt, manure or body sweat to maintain cleanliness and maximize success.
12. Stress
Stress occurs when an animal struggles to cope with its environment and can stem from various things, including health issues, poor animal handling, overstocking or sudden environmental changes. Each can negatively impact fertility. Preventing or minimizing stress is key for optimum reproductive performance. Low-stress handling benefits both cattle and handlers by improving safety and reducing stress levels. On the day of artificial insemination, low-stress cattle handling is particularly important to support pregnancy success.
Post-A.I.
13. Transportation
After artificial insemination, females often need to be relocated. However, handling and transportation during early pregnancy can cause stress, which could result in reduced pregnancy rates. Before day 5, the embryo remains in the oviduct and is not negatively affected by stress-related changes in the uterine environment. However, around day 5, when the embryo enters the uterus, the risk of pregnancy loss greatly increases, since the environment can now be affected by stress-related disruptions. To minimize this risk, it is recommended to transport cattle either within four days of insemination or after 60 days of gestation if possible.
14. Pregnancy diagnosis
Keeping non-pregnant females until the calving season has negative economic implications, as they incur the same costs as pregnant females but produce no income from a calf. Pregnancy diagnosis allows for early identification of open females, enabling more informed culling decisions. It also helps group females by gestational age, improving both calving and future breeding management.
15. Herd records
Maintaining good herd records allows you to keep track of which females meet your herd goals, which ones consistently conceive to artificial insemination or which calve unassisted and wean a heavy calf each year. By recording this information, you can make more informed culling decisions and remove less fertile or underperforming females while also selecting the best genetics for the future of your herd.
Unfortunately, there’s no silver bullet for ensuring pregnancies. However, by carefully managing the key factors mentioned above, you can significantly improve your chances of a successful breeding season.
