Feed them right early and have them at breeding weight in time
The goal for selecting replacement heifers is simple—you want them to conceive, calve early in the calving season, provide adequate milk production and produce a calf every year. But much of what makes a good replacement heifer begins long before you begin to eye the keepers. Dam nutrition has distinct and long-term implications for replacement heifers.
Heifer development is influenced by how the cow carrying the heifer was fed prior to the heifer being born. While you are familiar with the challenges of calf vigor born to dams calving thin, you might not know about studies that show how appropriate protein supplementation to late-gestation cows has a lasting effect on heifers.
Work at the University of Nebraska looked at the effects of nutrition of dams on growth and reproductive performance of their heifer calves. One group of last-trimester cows got a pound of 40-percent protein supplement three times a week, the control group didn’t. In the study, cows were managed similarly during calving and breeding. The research lasted three years—long enough for researchers to get a good look at the effects of feeding an appropriate protein supplement to late-gestation cows. Results showed that supplementing cows with protein during late gestation made for heavier heifers at weaning and breeding. Moreover, the heifers from protein-supplemented dams had higher pregnancy rates and earlier calving dates.
Aside from successful nutrition during gestation, pre-weaning management of heifer calves influences lifetime productivity. Heifers should be programmed to calve early during their first calving season. They will tend to calve early and wean heavier calves throughout their lifetime. Poorly developed heifers will fail to conceive or will calve late the first year and wean lighter calves.
Many of the heifers that calve late will be open after a limited breeding season.
With that in mind, there are several goals to work toward when developing heifers. Hopefully they will: 1) reach puberty by 12 to 14 months of age; 2) achieve high percentage for conceiving early in the breeding season; 3) be structurally large enough to minimize dystocia.
Due to the record-high value of feeder heifers and the high cost of developing replacement heifers, it makes sense to pay attention to genetic factors when selecting and breeding replacement heifers.
As stated above, selecting potential replacements from heifers born early in the calving season will make it easier to assure that they do the same when they calve.
Along those lines, the cost of using proven AI sires can be justified in the immediate added value of offspring from the insemination. And, it will pay in other ways in the future. One way this practice proves its future value is that heifers that conceive to AI have proven their ability to conceive early under a process that often has a lower conception rate than natural service. Odds are high that she will continue to do so in future years. Plus, bull calves from the AI services should be heavier and have predictable performance based on high accuracy EPDs. There are also well-documented advantages for multi-generational “stacking” of those predictable traits in future replacement heifers.
Feeding Replacement Heifers
Develop a ration geared toward adequate growth, not fattening. Given typical weaning ages, medium-frame heifers need to gain about 1.5 pounds per head daily from weaning to breeding. Large-framed continental breeds and crosses need to gain more than 1.5 pounds daily. Puberty is a function of both age and weight, so rate of gain can vary during the development period. Just make sure heifers reach the desired weight and appropriate body composition before breeding time.
To ensure that all heifers reach these weights before breeding, feed them separately from the cow herd. If possible, sort according to size. Smaller heifers require a more nutrient-dense diet and a higher rate of intake to attain target weights in the same timeframe as larger heifers. Remember that feeding replacement heifers similarly to terminal heifers will push the replacements heavier than they need to be—a costly proposition these days. Moreover, heifers that gain too fast have a tendency to have lower lifetime productivity, another costly proposition.
To determine the average daily gain needed for a group of heifers, subtract their average weight from the desired weight at breeding, and then divide by the number of days of feeding before the start of the breeding season.
Most heifers need to gain 1 to 1.5 pounds per day during the feeding period. Nutrient requirements for growing heifers to gain at these rates are listed in the nearby at right. These requirements are based on neutral conditions. Housing and other environmental conditions drastically influence the energy requirement of the animals.
Many combinations of feeds can be used for growing heifers—as long as intake and nutrient composition are appropriate. If you have to allow for error, it is better to overfeed protein than to overfeed energy. Heifers need to be grown rapidly but not fattened, so better-than-average forage should be offered. If heifers are on stockpiled pastures, they should be fed at least four to five pounds of Trendsetter Developer per head daily to attain the recommended weight gains; two to four pounds per head per day is the lower end of the feeding rate. Often, the feeding program can be divided into one of four scenarios: 1) the operation has a forage base; 2) the operation also has grain storage; 3) the operation uses grain co-products; 4) the operation uses corn or sorghum silages to develop heifers.
Taking periodic measurements of animal weight and height are helpful in determining if heifers are growing at the proper rate. Some cycling, estrus activity should be observed in the heifers by six weeks prior to the breeding season. If you don’t see estrus activity six weeks or so prior, it’s likely that the heifers are smaller than they need to be. If that’s the case, you have roughly a month to get enough weight on them so they will be cycling at breeding. If the situation arises in which you need to put on weight on a deadline, feed Full Throttle or Cattle Charge at two percent of bodyweight per head per day along with free-choice forage.
Dr. Jim White is ruminant nutritionist for MFA Incorporated. Mike John is director of MFA’s Health Track program.
A herd of Cows in good flesh has more calves and weans heavier calves.
Variation in the body condition of beef cows has a number of practical implications for your herd. The BCS of cows at calving is associated with length of postpartum interval, subsequent milking performance and newborn calf health and vigor. Excessive condition is often overrated as a cause of difficultbirthing in older cows, although fat heifers are known to be prone to calving difficulty. The condition of cows at breeding affects their reproductive performance in terms of service for conception, calving interval and the percentage of open cows.
What producers can do now, a couple of months ahead of spring calving, is sort the cows according to condition. If you can see ribs, they are going to be less than a BCS 5. Feed that group to gain weight. Cows that are 5 to 7 BCS should be sorted to be fed for maintenance to a slight gain. Finally, I have not seen many cows over 7, other than some pets and ET cows. So we’ll leave that group out. (For help judging body condition, see Today’s Farmer Summer 2011, p34.)
Why is having cows in good condition important? Because it makes a difference when cows get bred. If a cow doesn’t get pregnant, she’s a cull or a real money sink. Research in Florida looked at several different measurements, and having a BCS greater than 5 drastically improved the chances of a cow surviving preg check.
In the nearby chart, you’ll see the percent of cows that reached heat within 80 days after calving was lower for cows with a body condition of less than 5 than for cows scoring more than 5. Low body condition can lead to low pregnancy rates consistent with the reports of the other four trials. When cows are thin, the calving interval increases. To compensate for increased production costs, calves from cows with extended calving intervals must have a heavier weaning weight than calves from cows with shorter intervals, or an increase in sale price must occur. Depending on either factor for profit is a questionable assumption. With thin cows, long breeding seasons are sometimes suggested. This is not the profitable answer. Even after five and six months of breeding, the cows scoring less than 5 at calving and during breeding did not conceive at an acceptable level. Until they have regained some body condition or have had their calf weaned, most thin cows will not rebreed regardless of how long they are exposed to bulls.
Getting weight back onto cows
The practical management implication is to supplement cows based on body condition score. Body condition significantly alters the requirement for supplemental energy and slightly alters the need for supplemental protein, but it is not a determining factor of mineral or vitamin supplementation.Mineral supplementation is always required in that plantbased feed sources are always multiple mineral deficient. In addition to body condition, cow nutrient requirements are influenced by weight, mature size, breed type, milk production level, travel and environmental stresses. All things being equal, younger cows are going to need more pounds of supplemental feed than older cows. If we feed to satisfy older cows’ needs, the younger cows will be shorted. Also older, bigger cows are better at pushing and shoving—that has a big impact on supplemental feed intake, especially where supplement is modest (say feeding two pounds of cubes a day on the ground). If possible, separating cows by age, size and BCS is helpful.
One of the most crucial factors influencing the calf’s survival and performance is the degree to which the calf absorbs enough immunoglobulins from the colostrum to protect it until the calf ’s own immune system becomes functional. How the dam is fed influences colostrum quantity and quality. Cows fed lower-energy diets have been shown to have reduced colostrum yield and reduced colostrum solids—in other words, a lower level of immunoglobulins. This is troublesome on both accounts, in that lower yield means less volume to feed, combined with lower concentration reduction in available immunoglobulins to the calf is inevitable. Feeding adequate vitamin E and selenium has been shown to improve colostrum quality, as has feeding beta glucans and mannan oligosaccharides. MFA Ricochet cow products have been fortified with the specific additives and nutrients to encourage higher colostrum quality.
Dr. Jim White is ruminant nutritionist for MFA Incorporated.
Focus on immune system increases calf survival and early growth
As I get more grey hair, I more frequently recall that, in days past, it was easier to be an animal nutritionist. Nutrition has evolved to include topics of physiology, microbiology, psychology and immunology. The explanations from immunology have been very helpful in explaining how health challenges will have a big effect on an animal’s growth and productivity.
Years ago, Dr. Tim Stahly convinced me. He demonstrated that young pigs kept away from disease exposure grew at a tremendous rate. He showed that when litters were split and some pigs were kept clean, and others had their immune systems turned on by disease exposure, the challenged pigs grew slower. Activating the immune system is metabolically expensive—upwards of 10 percent of nutrient intake can be used in an immune response. This pulls nutrients away from growth. Couple that with reduced feed intake for the challenged animal and performance suffers.
Over the years, we have used a number of health-immune system modifying compounds—feed additives such as direct-fed microbials, fermentation products, botanicals, yeast-cell wall components, beta-glucans, etc. Over the years, MFA has evaluated nutritional means of improving calf performance. And while we’ve made very successful feeds, we also realized that calf performance doesn’t start when they are weaned—it starts before the calf is born.
Work in the 1980s at Ohio State demonstrated that the vaccination status of the dam influenced the amount and type of immunoglobulins she would produce in colostrum. The quantity and quality of colostrum has a huge effect on calf survivability and performance.
At birth, the calf is relativelyunprotected from disease organisms, and it takes awhile for the calf to develop its immune system. Until it does, calves are very dependent on the passive transfer of disease-fighting immunoglobulins from colostrum.
Strong fence and close weaning proximity helps calves
One weaning practice that continues to gain favor with both researchers and producers is fenceline weaning. Fencing companies also seem to be proponents—the practice requires good fences. This weaning system breaks the cow/calf bond through a fence, rather than waiting to the point the cow begins to kick the calf or physically separating the calf and dam separated by large distances. In this system, the pairs are separated but can still see, hear and have nose-to-nose contact. The result is a calf that bellows less, walks the fence less and, in general, is less stressed than a calf that is abruptly weaned. Research shows that fenceline weaned calves continue a close-to-normal growth rate and weight gain.
While this practice is relatively simple, it does require some space and a sturdy separation fence. The fenceline weaning process is a follows:
• Cows and calves are maintained together for several days in a pasture with ample feed resources.
• Calves are held here with dams so they can acclimate, find feed and water before separation occurs.
• To separate the pairs, the cows are moved to the other side of the fence.
• Pairs are kept separate until the bawling stops, usually about 5 days.
The better type of fence to have between the cows and calves would be either high tensile electric wire or woven wire with a start-your-heart electric charger on it. One of the critical keys to making this practice work is that the calves stay in a familiar place—an environment with the same feeding routine: a creep feeder full of Cattle Charge, same grass, same water. They will still have visual contact with their dams so the only change they undergo is no longer being able to nurse. Minimizing stress and change for calves is a big benefit in post weaning health and performance.
What do calves want? Just like their moms, calves want to be bored. An exciting day for a calf is one where he meets lots of new friends, gets vaccinated, ear tagged, hauled, dehorned, castrated, wormed, implanted and weaned. So you can see that an exciting day is really a bad day in terms of stress. Calves would much rather fill their rumen and contentedly stare off into space, in a semi-catatonic state and contemplate the bovine.
If you try fenceline weaning, after the initial separation, expect the calves to walk the fence for about 18 hours. After the first day, they will spend more time eating than bawling. As mentioned earlier, a crucial component of this program is the fence, it needs to be strong and tight. It virtually needs to be “hog tight.” Using a tight five-wire fence with a middle electric wire has been demonstrated to be adequate, you can bet that a single piece of electric tape is not. When the calf is weaned, the animal will have a markedly increased water intake, so it is important to ensure that the calves have adequate water.
A substantial benefit to fenceline weaning is the health of the calves. The incidence of calves needing treatment is lower for fenceline weaned calves than it is for calves abruptly weaned by hauling them to a drylot. The reduction in morbidity is attributed to the reduction in calf stress.
Dr. Jim White is ruminant nutritionist for MFA Incorporated.
Recently, a customer asked about bloat prevention in stocker calves weighing 500 to 600 lbs. He wondered if there is a mineral source for preventing bloat. And what about feed?
I have a short answer and a long answer.
To avoid a situation in which bloat occurs, I recommend feeding for maximum efficiency. Using a supplement such as Trendsetter with Rumensin (that’s my first choice) or Bovatec gets you there, and fine-tuned rumen helps prevent bloat. Likewise, I’d use Stocker BT Mineral (because calves that size will not eat enough of Rumensin 1620 mineral, and it is not a standard item).
Alternatively, I would feed Bloat Guard, either as bloat blocks or in the supplement. And, of course, I would try to limit things that encourage bloat—
alfalfa, soyhulls, wheat pasture, etc.
The longer answer in how to prevent bloat is to understand what causes bloat and how bloat affects cattle.
Animals bloat because they can’t pass gas from the rumen. While gasses from the rumen would normally back flow into the lungs and expel as belching, bloat occurs when the gasses mix with the content of the rumen (think lush grass cud) to form a foam.
The gas then becomes trapped in the rumen because the animal’s body reflexively will not allow foam back into the lungs.
I tell producers it’s like straining cream through cheesecloth. I can pour cream through cheesecloth. But if I whip air into it and beat the cream into “stiff peaks,” it will sit on cheesecloth.
To solve bloat, you need to break up the foam, or better yet, keep it from forming.
The foam is basically stabilized by protein. (Consider the bubbles baked into bread. The matrix that traps gas in a raising loaf of bread is a protein/gluten matrix.)
Signs of bloat
• animal will be high on the left side, behind the ribs
• animal will not want to move
• animal exhibits distress—eyes bulge, tongue may protrude, exhibits bawling
• animal strains during urination/defecation
• animal exhibits rapid breathing
• animal staggers
Essentially, an animal suffering bloat smothers because the pressure on the lungs keeps them from getting enough air. An animal that dies from bloat will have congested lungs and a classic bloat/blood line. Observing the animal puffed up like an inflated disposable glove is not proof of death by bloat, however, as a different set of gasses kicks in after death.
Practical advice for mild cases of bloat
Treat with a surfactant—something that breaks down the foam (i.e. BloatGuard, detergents) Make sure animals keep moving and provide ionophores in the feed—ionophores have been shown to reduce the viscosity of rumen fluid/foam.
I use Rumensin as the product of choice for feed efficiency, but people with horses tend to fear Rumensin. If I have had problems with calves bloating on Cattle Charge, I use Cattle Charge with Rumensin, and have not had re-occurrence of bloat. Note that while Rumensin is approved for bloat in Mexico, it is not approved for bloat in the U.S. Here, we focus on using Rumensin for performance/feed efficiency.
Practical advice for severe bloat
For severe cases, immediate intervention is needed. Treatment is usually with a trocar. In my experience the trocar is placed at the crown of the bulge, with care taken to avoid veins and arteries. But do get veterinarian consultation and help before you intervene. Sometimes the trocar doesn’t seem to punch a big enough hole and the hole is opened up with a stiff bladed knife, again, the territory best trod by a vet. Once the trocar has done its work, surfactant is introduced through the hole. The cuts will need to be cleaned up and sewn up. Using a trocar is quick, but the subsequent clean up is tedious, and not without risk of infection. Alternatively a stomach tube can be introduced. Expect a splash.
Prevention of bloat
When faced with grazing risky pasture such as legume pastures dominated by alfalfa and to a lesser degree clover (mixed grass clover swards of less than 40 percent clover are relatively bloat safe) or wheat pastures, consider these steps:
• Restrict pasture intake through limiting grazing time
• Strip graze by allocating a fraction of the pasture to the herd
• Feed hay or other feed prior to putting them out on the suspect pasture
• Use a surfactant such as Bloat Guard
• Supplement feed with an ionophore
Dr. Jim White is ruminant nutritionist for MFA Incorporated.
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