SIX ESSENTIAL PRACTICES FOR REPRODUCTIVE EFFICIENCY

Six Essential Practices for

REPRODUCTIVE EFFICIENCY

By Lee Jones, DVM, MS, University of Georgia

Reproductive efficiency is crucial for cow/calf herd production and profitability. Without pregnancies, calves aren’t born or weaned and sold. Pregnancy has significantly greater economic impact than any other production trait, and reproductive efficiency is more important than growth or carcass traits for the cow/calf producer. There are a lot of things that challenge reproduction in our cow herds. While fertility is the single most significant factor for cow herd success, infertility is considerably costlier than scours, calf respiratory disease or any other non-fatal disease. Infertility can be defined as a cow failing to breed, breeding but not delivering a live calf, or breeding late. The fact is that if the calf isn’t born alive and healthy and weaned, we don’t have anything to sell. There are six key management areas essential for reproductive efficiency for beef cow/calf programs: heifer fertility, cow herd management, bull fertility, controlled calving season, pregnancy diagnosis, and culling.

Heifer Fertility

Selecting heifers for fertility and longevity is essential for lifetime productivity. Numerous studies have shown that heifers that breed early and calve early (first 21 days of controlled calving season) are more productive over their lifetime and stay in the herd longer than heifers that calve later. Heifers that calve early as 2-year-olds and maintain early calving throughout their lifetime can produce 100 pounds more calf each year than heifers that calve two cycles later. Traditional methods of heifer selection rely on physical traits such as weight, age and pregnancy status to determine who to keep. Genomic tools show potential to improve our ability to identify the more productive heifers earlier than traditional, phenotypic selection tools. However, selecting heifers by physical traits and overall phenotype is still a valuable tool to build a fertile cow herd. Proper management and selection of heifers that will conceive early is critical. The use of estrus synchronization and AI to breed heifers at the beginning of the breeding season is also an effective tool to produce productive heifers that have longevity.

Cow Herd

Managing body condition of the cow herd is the best practice to maintain reproductive performance in herds. The cow’s body condition at calving determines her opportunity to get bred in the next breeding season. Cows that calve in poor body condition (BCS 4 or less on a 1-9 scale) likely will not be cycling when the bulls are turned out and have fewer opportunities to get bred than a cow that calves in good BCS. Cows that calve in BCS of 5 or 6 are usually cycling by 60 days after calving and have a better chance of maintaining a 12-month calving interval. Likewise, if a cow calves late

in the calving season, she will have fewer days to get bred back. Managing cows to calve early and maintain adequate body condition during the dry period helps cows get rebred. The ideal time to improve cow body condition is between weaning and calving. Colostrum quality is also affected by cow body condition. So, managing for BC improves not only fertility but calf health as well.

Bulls

Managing our bulls is another important part of reproductive efficiency of the herd. Using fertile bulls will get more cows bred earlier than using sub-fertile bulls. Several studies show the benefits of a thorough annual breeding soundness exam (BSE) consisting of a physical examination, a thorough reproductive tract examination, and a semen evaluation including checking motility and morphology of the sperm. Bulls that pass a BSE produce more calves and heavier calves than bulls that don’t or bulls that haven’t been examined. Fertile bulls get more cows bred in the first service. Sub-fertile bulls can take two or more services to get cows bred. Every cycle a cow goes open is 40-50 pounds of calf lost at weaning, so testing bulls and using only fertile bulls helps keep more cows bred and bred early.

While bulls should be low-maintenance during the offseason, it is easy to neglect their basic nutritional needs. Bulls need to maintain good body condition and be in good condition for the breeding season; BCS 5-6 is optimal. However, a bull can be in good condition and still fail his BSE due to mineral and vitamin deficiencies. Therefore, a complete nutrition plan for the bull pen including adequate vitamins and minerals is essential.

Controlled Calving Season

Having a controlled calving season helps facilitate efficient, effective cow herd management not just for feed efficiency and body condition but also for herd health. Matching herd production with forage availability is essential for efficient herd production. It is important that the cow herd’s highest nutritional needs coincide with the availability of sufficient, high-quality forage. Feed cost is the single highest expense in a cow herd. The most efficient herds manage their cow herds so cows satisfy most of their nutritional requirements through grazing available high-quality forage.

A controlled calving season also facilitates better herd health programs. Cow and calf vaccination programs can be better timed for more effective protection and convenience, and to allow for more vaccine protocol options. Other advantages include better marketing options and more efficient use of labor and calving season supervision.

Pregnancy Diagnosis

Overall, only 1 in 5 beef herds are checked for pregnancy each year. This is a real opportunity to improve cow herd efficiency. Some farmers claim that it’s too expensive (compared to an open cow?), they don’t have time, the facilities aren’t adequate, they can’t get a vet – and the excuses go on. However, anywhere from 10 percent to as high as 35 percent of the cows exposed to bulls don’t calve each year. Removing these non-productive cows from the herd can save in winter maintenance costs. Not only does it save by not paying to keep non-productive cows; removing the non-productive ones frees resources for the productive cows, improving their production and fertility. Producers have several effective techniques to find open cows today. Blood tests, rectal palpation, ultrasound and even heat patches are all proven tools to find open cows.

While knowing pregnant or open status is important, knowing the age of gestation is even better. This allows for better pre-calving season decisions. Collecting additional data, such as body condition score (BCS) and condition of teeth, is also helpful for managing cows. Thin cows can be fed or turned onto better pasture to gain BC before calving. This improves calf health and cow fertility. Cows with short or missing teeth can be fed differently or just culled if feed inventory is marginal.

Each cow must pay her way each year, either with a calf or with her own sale value.

Culling

All cows are culled or cull themselves eventually. However, strategic culling is in the best interest of the cow and the farmer alike. Most cows are culled due to not being pregnant or not having a calf. Yet, some might be culled due to injury, disease or just not being very thrifty. Cows with a bad bag have been shown to have calves with more health problems or higher calf death loss and poorer-doing calves. Cows that have eye problems, including possible cancer eye that is very small, lame or bad feet and legs, poor disposition, or calves that just don’t perform as well as those of the other cows in the herd can all be considered for culling. It takes just as much grass to keep a good one as a bad one, said a wise farmer. Older bred cows can be calved and kept in a separate pasture with no bulls if it’s their last year. This could save on bull power, too, since they don’t need to get rebred.

We don’t have a sure way to predict when or if an older cow will get injured or go down on us, but keeping a cow beyond her productive years is taking a chance that she might not be marketable one day and we lose that income. While some cows might earn a special place in the pasture in their twilight years, most cows need to be evaluated as they get older to make sure that they leave the herd on our terms.

Reproduction is more than just getting cows pregnant. It is also about getting live healthy calves and helping them grow to their genetic potential, getting cows to rebreed after calving, and getting cows to produce enough milk for their calves to grow and flourish. A few simple steps and a strategy to manage our herd’s fertility will make for some good healthy productive cows and a lot of personal pleasure of raising good cattle.