Cow Health for Breeding - Have them ready to Breed

Published on Mon, 04/03/2023 - 2:57pm

Cow Health for Breeding - Have them ready to Breed.

 By Heather Smith Thomas.

 In order to breed in a timely manner, especially after calving, cows need to be in good body condition, healthy and cycling again.  Disease prevention and adequate nutrition are probably the most important factors in having females ready to breed on time—whether heifers being bred for the first time or cows that have calved and need to be rebred for their next calf.

Disease Prevention
Develop an appropriate vaccination schedule for your herd to prevent the most prevalent or devastating diseases in your region.  Some diseases come into a herd via wildlife, insects, or bacterial spores in the environment. Vaccination is the only way to prevent these diseases and should always be part of your herd health plan.  The vaccines you use will depend on your region and risk for transmission.

Some diseases directly affect reproduction, interfering with the cow’s ability to carry a calf to term.  These include IBR, BVD and leptospirosis.  We try to prevent these diseases by making sure cows and heifers have adequate immunity before breeding, according to Dr. Tom Hairgrove (Extension Veterinarian, Animal Science, Texas A&M).  There is also some risk in vaccinating cows the day you turn the bulls out.  It’s better to vaccinate at least 30 days prior to turnout, as vaccinating too close to breeding can cause pregnancy loss.

“I recommend vaccinating replacement heifers at weaning—with a modified live virus (MLV) vaccine for IBR and BVD—and a booster pre-breeding, preferably at least 2 or 3 weeks before breeding.  But many people are using AI on their heifers and want to give that last MLV dose when they have the heifers in the chute to synchronize.  There is controversy regarding whether to use MLV vaccine at that time, so I recommend using a killed product in that situation,” he says.  Vaccinating according to label prior to breeding would give protective immunity for reproductive diseases. 

He also recommends using vibrio vaccination (campylobacter), especially if you don’t have a closed herd or don’t know the status of your neighbor’s cattle, or run yours in a community pasture.

Discuss a vaccination program with your veterinarian, to figure out which diseases to be concerned about, and how often you should vaccinate.  Don’t forget parasite control. Even if cattle look healthy, internal and/or external parasites may rob them of nutrients, resulting in slower growth in calves, less milk production, less efficient immune system, or poor reproduction (lower conception rates).

Also keep in mind that stress contributes to higher incidence or severity of disease.  Stressed cattle do not eat well, so stress interferes with proper weight gain, reproduction and disease resistance.  Some of the hormones produced by the body during stress can also interfere with reproduction.

Importance Of Nutrition
Adequate levels of important nutrients are crucial for reproduction, since the body always takes care of other needs first.  Reproduction is a luxury that won’t take place unless maintenance needs are met.  A thin cow or heifer will not settle as readily as an individual in good flesh; if she is too thin she won’t even cycle.

Spring calving cows must be in good flesh through winter.  Cows that are thin at calving take longer to start cycling again.  Monitor body condition through winter to make sure your feeding program is on target; the easiest time to put flesh back on a cow if she’s pulled down after summer lactation is in the fall after weaning her calf—before weather gets cold.  A pregnant dry cow should gain weight on pasture alone, with just a protein supplement if grass is overly mature with low protein content.

If a cow is thin at calving, it’s hard to pick up her weight after she starts lactating.  She puts the extra energy into milk instead of body weight.  A fat cow can coast through winter and even lose a little weight without detrimental effects, whereas a thin cow needs to gain weight through winter if you expect her to breed back.  You don’t want cows losing weight just before or after calving.  If two cows have the same body condition at calving, if one is losing weight and the other is gaining, the cow gaining weight is better programmed for fertility than the cow losing weight.  Studies have shown that each 10% of weight lost before calving can delay the first heat cycle by about 19 days.  So you want cows in good flesh at calving.

Dr. Travis Mulliniks (Beef Cattle Nutritionist,University of Nebraska–Lincoln) says gestation length in cattle is about 280 days.  “We need cows to recover and rebreed within 80 to 85 days post-partum.  The issue we run into is that the majority of young cows are hard pressed to recover and start cycling by day 80.  We need to focus on how we can get these cows cycling as early as possible so they can maintain calving interval,” says Mulliniks.  Cows that cycle later may calve late the next season or come up open.

The earlier we can get those cows cycling, the more we increase their opportunity to stay in the cow herd longer.  “One way to do that is to get them gaining body weight as soon as possible after calving.  Cows that lose a little weight in late gestation can rebound after calving, to compensate, and pregnancy rates increase.  Once a cow stops losing weight and starts gaining again, within 10 to 12 days those cows will start cycling again.  This increases their chances to get bred quicker,” he says.

“Post-partum nutrition has a huge influence on when those cows start cycling,” says Mulliniks. “We can get away with nutritional levels that are not quite meeting their needs during late gestation if we supply the right nutrients after calving (when lactation greatly increases their needs) to get those cows gaining body weight as soon as possible, to compensate for that nutritional low prior to calving.”

One study looked at cows gaining one pound per day after calving, versus cows gaining two pounds per day.  “This research looked at when they got pregnant within a 60 day breeding season—whether in the first 20 days, first 40 days, or by day 60.  By simply gaining a pound more per day, they increased the percent that got pregnant in the first 20 days by about 20%.  This can make a big difference.  If we can get cows to gain weight as soon as possible after calving, going into breeding season, we can greatly influence the timing of when they get pregnant,” he says.

In some instances, however, too much nutrition can be as detrimental as too little.  A cow or heifer that’s too fat may have fertility problems.  A fat cow or heifer will tire more readily during labor—requiring assistance to deliver the calf in timely fashion—and she may take longer to recover from calving.

Cows consuming excessively high levels of protein after calving will have problems, according to Ron Skinner, DVM (veterinarian and seedstock producer near Hall, Montana).  Skinner consults with ranchers on nutrition and mineral programs, and also helps them resolve breeding issues when they have low conception rates, such as 50% with embryos or only 60% with AI. “When we make changes in the rations, these rates improve,” he says.

“When I started doing embryo work in my own herd 45 years ago, I thought I could help those cows by putting them on high quality alfalfa hay.  I learned several things—first that they eat too much because they really like it, and it goes through them too fast (and they have very loose manure).  One of the problems with feeding a high protein diet is that it builds up a too high urea level in the uterine fluids, blood stream, and changes the pH, and this really hurts conception rates,” says Skinner.  He learned to adjust the protein level in diet to a more optimum level, rather than maximum level.

One of the most important aspects of nutrition is to make sure trace mineral levels are adequate, since many regions are short on copper, zinc and selenium.  It pays to check hay for mineral levels.  These may be low, or rendered unavailable to cattle if tied up by other minerals.  “Three things that can tie up trace minerals are iron, sulfur and molybdenum.  Excessive amounts of these interfere with the body’s absorption of trace minerals,” says Skinner.  This can cause weight loss, delay in puberty for heifers, and create health issues because trace minerals are important for a healthy immune system.

Adequate levels of trace minerals in the diet are especially important in the 60 days before calving, and after calving—through breeding.  “Nearly 70% of the U.S. is copper deficient, and about 50% is zinc deficient,” says Skinner.  Certain geographic areas are also very selenium deficient.  You need to know what your soils and feeds contain, so you can make adjustments if needed.
“I don’t think we should go overboard on trace minerals, but there are times in the beef cow’s year that we really need them, such as in late gestation to help build a healthy immune system in the fetus, and before breeding,” he says.  

Young Cows Have Special Needs
Dr. Colin Palmer, Western College of Veterinary Medicine, University of Saskatchewan, says one thing people recommend is breeding heifers a few weeks ahead of the cows.  “Heifers tend to have a longer post-partum recovery period than cows and are slower to start cycling again.  To overcome this, some ranchers have heifers calving one cycle length (three weeks) earlier than the cows.”  This gives them more chance to breed back again.

“Two main things determine cyclicity in heifers.  One is age and the other is body size and condition.  Larger body size goes along with older animals, but feeding can also play a role.  We used to talk about feeding heifers to reach about 2/3 of their mature size before their first breeding season.  But work done by Bart Lardner and Kathy Larson at Western Beef Development Centre, where they looked at feeding heifers to 50 to 55% of their mature weight rather than 65% found that feeding to 55% was adequate in their Angus-based breeding herd.  Their long-term study showed no negative effects.  You can feed heifers to lighter weight, if you make sure your feeding program is sufficient to achieve the target,” says Palmer.

“Another thing that can help first calvers is to manage them separately, if possible, rather than having them with the mature cows for winter feeding.  They don’t compete well with larger, more dominant cows.  The cows push them away from the feed.  If a person can’t keep them in a separate group, however, there are ways to manage the feed so they have more chance to eat it,” he says.

“I run first-calf heifers with cows, but try to distribute the feed evenly.  Rather than using bale feeders, where there might be a bunch of cows eating on the best bale and keeping the others away, we roll out the bale so it’s spread farther.  There’s more chance for them all to eat it, and have a chance at the same nutrition.  We also changed our mineral feeding so that it’s in long troughs rather than just a few tubs.”  If separating the heifers from the cows isn’t possible, a person can be innovative to give them all equal access to the feed or supplement.

“It’s important to have young cows in decent enough body condition by the time they hit the breeding pasture,” Palmer says.  “Make sure they are not too fat nor too thin.  It’s very hard for them to keep up, after calving—when they are lactating, and still trying to grow.  They need the best hay, or the best pasture, between calving and rebreeding.”