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By Heather Smith Thomas Optimum health and strong immunity depend on adequate nutrition, and this includes important trace minerals, especially copper, selenium, zinc and manganese. Some soils, and the feeds grown on those soils, are short in these minerals. Many livestock producers use supplemental minerals, in the form of salt-mineral mixes, to augment cattle diets, but consumption is varied. Some animals consume too much while others eat inadequate amounts or none at all. Most feedlots add the necessary minerals to a grain ration, but feed consumption of shipping-stressed cattle coming into a feedlot is typically low, especially the first 7 to 10 days. Because of these variables, some producers resort to individually dosing the animals by drench, bolus or injection to make sure the cattle receive the necessary minerals. In recent years, science has recognized the value of injectable trace minerals — selenium, copper, zinc and manganese. Dr. Lourens Havenga, a veterinarian and chief executive officer Three studies were recently done on stocker-feeder cattle. “These studies were all done during the receiving period at the feedlot, and these were high-stress cattle,” Havenga says. These 3 studies were done at the Universities of Arkansas and Missouri, and Oklahoma State University. The researchers found that adding a trace mineral injection to the processing protocol (vaccinations and tagging) for incoming cattle made a positive difference in their health and feedlot performance. “These trials looked at average daily gain, feed conversion, number of treatments (for health problems), number of retreatments and the antibiotic costs. They found a significant improvement in health of the mineral-treated cattle in all 3 studies, and a significant decrease in antibiotic costs,” he says. University of Arkansas
Upon arrival, the calves were weighed, and averaged 438 pounds. They were tagged with an individual ear tag number and vaccinated with a 7-way clostridial product, 5-way viral respiratory product and a Pasteurella vaccine. The calves were sorted by initial body weight (heaviest to lightest) and put into 5 weight categories. They were randomly allocated to 1 of 3 treatment groups. Two groups received injected minerals (2 different products) and the third group was the control group and was left untreated. On Day 14 all calves were treated for internal and external parasites. All calves were offered free-choice access to a common receiving ration for the 55-day trial period and were evaluated daily for clinical signs of respiratory disease. They were also checked for any signs of inflammatory response (swelling) in the neck region where the mineral products had been injected. During the 55-day period, average daily gain (ADG) was similar for both groups of calves receiving injected minerals. The ADG for both groups was greater than the ADG of the non-treated control animals. ADG for the treated groups was 2.43 and 2.39 pounds, while ADG for the control group was 1.99 pounds per day. The treated cattle ate better and had converted the pounds of feed to pounds of gain more efficiently than the control animals. The 2 groups of calves that received minerals consumed 5.4 and 5.6 pounds of feed per pound of gain, while the control group consumed 6.2 pounds of feed per pound of gain. Calves were individually weighed upon arrival and on day 1, 14, 28, 54 and 55 to determine ADG. After the 55-day trial period the final body weight for the 2 mineral-treated groups averaged 572 and 568 pounds, compared with 548 pounds for the non-treated control animals. The mineral-treated calves had fewer cases of respiratory illness. The cost of antibiotic treatment was higher for the control group. Calves with 2 or more clinical signs of illness were brought to the chute to record rectal temperature. If it was greater than 104 degrees the animal was considered to be ill, given antibiotic therapy and was returned to its home pen. Morbidity rate (percent of calves showing illness) was 87.1 percent in the control group, compared with 54.8 and 67.9 percent of the mineral-treated groups. Fewer calves required a second treatment with antibiotics in the mineral-treated groups (19.4 percent and 17.9 percent), compared with the controls (51.6 percent). A few needed a third treatment (9.7 and 10.7 percent of the mineral groups, compared with 32.66 percent of the control calves). The average antibiotic cost per animal in the control group was $13.66. Average cost per animal in the 2 mineral groups was $9.47 and $8.07. The reduction in antibiotic cost (savings per animal) was greater than the cost of administering the trace mineral solutions (which cost less than $1.50 per animal). No injection site lesions were observed in the mineral-treated animals. Oklahoma State and
University of Missouri At MU, only 30 percent of the mineral-treated calves required antibiotic treatment, compared with 32 percent of the control group. Only 9 percent of the mineral-treated calves required a second treatment, compared with 12 percent of the controls, and no animals needed a third treatment. The Missouri study used 189 crossbred beef steers, some of which had been obtained from auction markets were considered at high-risk for respiratory disease due to their exposure to stress. Others of the group came from the MU herd. These weaned calves had been preconditioned for 45 days prior to the study and were considered low-risk for respiratory disease. The preconditioned calves had lower incidence of respiratory disease and had better ADG than that of high-risk steers during the finishing phase. Bovine respiratory disease negatively affects the profitability of cattle feeding due to death loss, expense of treatment and reduced growth rate. Mineral deficiencies have been proven in many studies to decrease the immune response of animals and thus increase their susceptibility to disease. “With these results, we are in a good position now to suggest that producers consider injectable products for use in feeding cattle, or when a person is buying stocker cattle and has to transport them and expose them to a lot of stress,” says Havenga. Several trace minerals, including selenium, copper and zinc, are crucial for proper immune function in cattle, and the results of these trials suggest that administering an injectable trace mineral solution to shipping-stressed cattle upon arrival at a feedlot may reduce incidence of respiratory disease when trace mineral levels are low or unknown. “Worldwide today, there is increasing pressure on stock raisers to use fewer antibiotics. Anything we can do to produce a healthier animal and cut down the need for and cost of antibiotics, will be a help,” says Havenga. Injected minerals
in cow-calf operations
Later, researchers found that copper deficiencies were also widespread, resulting in poor hair pigmentation, fragile bones, impaired reproductive performance, low growth rates and reduced immunity. Copper supplementation has improved conception rates and immune responses to vaccinations. The most recent forage and cattle studies have indicated that zinc may be the most widely deficient trace mineral. Zinc is important in many body systems including production of certain enzymes (particularly for synthesis of DNA, and proteins), carbohydrate metabolism, hoof structure and soundness, and male fertility (deficient animals have smaller testicles and reduced semen quality). Zinc-deficient calves may have swollen feet, scaly skin with open lesions, wounds that take longer to heal, loss of hair, excessive salivation, reduced appetite, reduced feed efficiency and growth rates, and impaired immune systems. Moderate deficiencies are not so readily recognized, but take an economic toll through decreased growth rate and impaired immunity and fertility. Calves born to zinc-deficient dams have lower levels of immunity even when fed adequate amounts of zinc. Manganese, another important trace mineral, is important for proper bone and cartilage formation, which directly affects bone growth in young animals. It is also crucial for optimum fertility in cows. Signs of deficiency in calves include skeletal deformities, swollen joints and stiffness. During the past 2 decades, USDA studies of blood levels for trace minerals in cattle herds around the country found numerous animals deficient in these 4 important minerals. In recent years, the value of injected trace minerals has been recognized as a reliable way to ensure that cattle receive them. Several university studies have shown the benefits of injected trace mineral products, looking at how rapidly the minerals are absorbed and how long they are stored in the liver. Other studies have evaluated the effects on calf health and reproductive performance when injecting cows before and after calving. “After launching our new product, I had a lot of questions from veterinarians and producers, asking how it actually works. For instance, after injection how quickly is it absorbed, how quickly does it go into the liver, how quickly do we see the different enzymes (that rely on these minerals) start showing response. So I contacted researchers at Iowa State University to do some studies,” says Havenga. “I met with Stephanie Hansen, Ph.D., who has done a lot of trace mineral research and she agreed to do the research. She provided us with an elaborate and detailed trial report, and presented her research findings at the Animal Science meeting in Denver in mid-July 2010.” Dr. Hansen found that the injected product is absorbed rapidly. “Once you’ve injected the animal, mineral levels in the bloodstream increase and reach a peak within 8 to 10 hours. Most of the mineral that the animal doesn’t utilize is stored in the liver, while some is excreted by the kidneys. The high blood level is maintained for about 24 hours and then drops. The body stores the excess in the liver, or gets rid of it in the urine or feces,” says Havenga. “We ran this study only for 15 days, and found that the storage levels were high for the full 15 days. We later had other studies done at Texas A&M that showed the product actually lasts (stored in the liver) for about 2 to 3 months, depending on mineral status prior to injection,” he says. “The third part of the research project at Iowa State looked at enzyme responses. It starts immediately, but by 14 days after injection significant changes were confirmed. This is why we recommend that producers use this product a little in advance of stresses, calving or breeding, especially for enhancing reproductive performance. It’s best if you can inject cows about a month before they’d be breeding, or about a month before calving (at a minimum) for optimum benefit. You can use it earlier than that, such as at pregnancy checking, but shouldn’t use it much closer to these events because cattle might not get full benefit,” he explains. A Texas A&M study in beef cattle came up with additional data regarding differences in cattle performance. An experiment was conducted to determine the effects of providing pre-calving and pre-breeding injections of Multimin and vitamin E on reproductive performance of beef cows, and on health and survival of their calves. In this study, 67 crossbred cows were randomly assigned to control or Multimin/vitamin E treatments. Treated cows were given injections 30 days prior to the start of calving and again 21 days prior to start of breeding. The trace mineral injections effectively improved copper levels (liver) and selenium levels (blood), compared to the non-treated cows. The treated cows had significantly higher liver concentrations of copper than the controls, remaining higher for 161 days after the last injection. Previous research had shown that cattle have improved performance and/or immune function with trace mineral supplementation when they are marginal-to-deficient in copper, zinc and selenium, but differences may not be seen when cattle have adequate levels to begin with. In the Texas study, more cows became pregnant in the treated group. Cows in the control group were 2.4 times more likely to be open. “Researchers injected the product before the cows calved, and again before they bred the cows. This showed that if you use the product strategically, these 2 injections can keep liver levels elevated in the cow for almost a full year (one production cycle). We stopped that trial at 256 days just before the cows started calving again the next season,” says Havenga. “The producer benefit in the Texas A&M study was increased calving percentage, and those cows also calved earlier. The Multimin-treated cows bred back quicker and calved 6 days earlier, on average, than the untreated cows,” he says. Making sure cows have adequate levels of trace minerals during pregnancy also ensures normal bone formation and immune system development in the growing fetus, and enables the fetus to have adequate stores of these important minerals in its liver. Deficiencies in the calf cannot be made up through supplementing the dam after calving, since these minerals do not transfer very well through the milk. Some producers cover their bases by giving young calves injections during the first days or weeks of life, or at branding time. Ideally, make sure the calf has peak levels (and is not deficient) at the time of vaccinations to be able to mount strong immunities. Unless the calf has adequate trace mineral status, vaccination may not be able to protect the calf against disease.
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