by: Lee Jones, MS, DVM
University of Georgia
Yes, I know you are in spring calving season if that's your program. So you might wonder why this article isn't about calving instead of breeding, which is still at least three months away. The thing is, what we do right now during calving will determine our success in the breeding season. Actually, what we did last fall after weaning impacts the upcoming breeding season as well; but that opportunity is behind us, so we need to focus on what we can do right now to prepare for a successful breeding program.
For the cow herd, the main concerns are adequate nutrition, maintaining cow body condition in 5 or 6 (scale of 1-9 with 9 being obese), and an effective health program including properly timed vaccinations. The body condition (BC) of the cow at calving is associated with the time the cow rebreeds after calving. The other factor is body condition or weight loss after calving. Cows that lose weight after calving breed back later than cows that calve in good BC and don't lose weight. The nutrient requirements for cows are the highest during early lactation (first three months after calving). It is critical that we provide nutritional supplementation during this period. This can be accomplished by feeding grain or a pellet supplement or providing access to high-quality winter supplemental forage. Most winter pasture and stored dry hay or haylage are not sufficient to meet the lactating cow's nutritional requirements. If farmers are relying on winter grazing for supplement, then it is important that the forage be sufficient in quality and quantity. This is very much dependent on rain and temperature (as well as the forage species) and can quickly become overgrazed. Owners should carefully monitor their winter forage pastures and provide other sources of supplement if needed. The amount of supplement needed varies and depends on the weather, cow condition, average cow size and age, as well as the protein and energy content of the supplement. Properly supplemented cows breed back more quickly in the breeding season than cows that do not receive sufficient supplementation. First-calf heifers are especially at risk of losing weight after calving and need particular attention to help them breed back and stay early in subsequent calving seasons. In many cases, it is better to manage them in a separate group and even calve them a little ahead of the main herd for best results. Providing a high quality free-choice mineral is also very important. Consult with a livestock nutritionist or a county Extension agent for more information.
The calving area should be protected from severe weather and flooding. Some folks like to calve in woods; this does offer some protection from the weather, but it is difficult to observe cows during calving and assist if cows are having difficulty delivering the calves naturally. It is important to assist cows and heifers as soon as problems are noticed. Early intervention improves the calf's chance of survival and helps the cow recover. Calving areas become contaminated over time, and the rate of contamination depends on the number or concentration of cows and calves. After four to six weeks, it might be advisable to move the dry cows to a fresh area. This allows newborn calves to calve in a cleaner environment and reduces the exposure to disease agents. Cows that experience problems during calving often breed back later than cows that do not have any problems. Assisting a cow that has trouble calving will improve her chances of breeding back sooner as well as raising a healthy calf. It is critical to use good hygiene when assisting a calf birth. We can cause an infection if we aren't careful, and that could cause infertility in the cow.
Vaccinating the cow herd improves calf health by enhancing colostrum; it also protects the fertility of the cow herd. Cow herd fertility can be impacted by viruses such as IBR and BVD and bacteria such as Leptospora spp. Vaccinating cows prior to calving helps improve the colostrum. Vaccinating prior to breeding allows for the use of a modified live viral vaccine in open cows. Annual vaccinations are recommended; but the choice of when – prior to calving or prior to breeding -- largely depends on the goals and opportunities of management.
The other important part of the breeding season is our bulls. Another option could be to breed some of the cows by artificial insemination. For the bulls, an annual breeding soundness examination (BSE) is recommended one to two months prior to exposure to the cows. A complete BSE involves a physical exam and internal exam, along with a semen evaluation using a microscope. It is important that the bull have good eyesight, sound hooves and legs, and be in good body condition. Some folks prefer to have a massage done, thinking it is less invasive and more humane. The risk is that the bull could have a defect that is missed by not having a thorough examination. Even if a bull has good-quality semen and sperm, he still might not be able to actually breed cows and sire calves. Open cows is a high price to pay for a quick, incomplete examination. Minimum criteria to pass a bull on a BSE are: no visible physical defects; scrotal circumference at least >32 cm (for a yearling bull); and a minimum of 70 percent normal sperm with at least 30 percent progressive motility. Bulls that pass a BSE have been shown to breed more cows in a shorter amount of time than bulls that were not examined or didn't pass a BSE. Bulls also need to be on a good plane of nutrition and have access to high-quality minerals. Hardworking bulls can lose a lot of weight during the season, so they need to be in good BC at the beginning of breeding.
Many owners have discovered the benefits of estrus synchronization and AI. If you are planning to use AI in your herd, it's a good idea to check the tank inventory and make sure all your equipment is in good condition and you have the necessary supplies on hand. Some companies run specials on sires, and that can be a good time to purchase the sires you want to use before the companies get busy with orders. Check the thaw box with a reliable thermometer. The temperature cards in the thaw boxes are acceptable to use but it is wise to have the box temperature checked with an accurate thermometer. If the temperature is off by a few degrees, it could mean that your conception rates could be off by a lot. Check the lube to see whether it has gone bad since last year. Insemination rods need to be clean and working properly; and make sure you have plenty of sleeves and sheaths.
For the best AI results, cows and heifers need to be in good condition (BC of 5) and on a high plane of nutrition.
If necessary, feeding cows and heifers some grain prior to breeding will dramatically improve the percentage of cows that conceive to the AI.
A successful breeding season doesn't happen overnight. Taking the time to prepare our cows for a successful breeding season starts months before we turn out bulls or start our synchronization program. Proper preparation ensures success.
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