Feed your fly control needs

Willis Bruce—not to be confused with actor Bruce Willis—spent his career studying horn flies. Bruce was an USDA entomologist and professor at the University of Illinois who designed an ingenious walk-through horn fly trap in the 1930s and worked to develop other control methods for these pesky little insects.

Dr. Bruce was particularly interested in the horn fly because it is one of the most widespread and costly external cattle parasites. Current estimates are that horn flies cost the American cattle industry some $2 million every day. Adult flies bite the animal, causing irritation and often drawing blood. As calves spend less time grazing, weight gains will be reduced by an average of 20 pounds per year. But losses may also go much higher:

  • Cows produce less milk and may fall out of breeding condition.
  • Horn flies have been implicated in the spread of summer mastitis, which tends to be highest in fly season.
  • Eye problems may result.

Horn flies are small—adults are about 3⁄16 inch, half the length of a house fly. They are dark gray, blood-sucking flies that stay on cattle almost continuously.

Both male and female horn flies are blood feeders that spend most of their time on the shoulders and backs of cattle. During extremely hot weather or when it rains, they may move to the more protected underside of the animal. They are not strong fliers. When disturbed, horn flies will swarm but return to animals almost immediately. Females leave occasionally to lay eggs in fresh manure piles. If horn flies are not on manure, they are on the animal.

The close association between horn flies and host helps with control. The flies leave animals only to lay eggs or to change hosts, so many methods will expose flies to control practices such as ear tags, topical products, feed-through additives, etc. With some chemistries, insect resistance has been an issue. If a producer applies fly tags, and two weeks later there has been no decline in fly population, the insects are likely resistant to the product.

Resistance is not a problem when using the insect growth regulator (IGR) s-methoprene, brand name Altosid. It has been very effective in controlling biting adult insects that have specific larval environmental requirements, including horn flies and mosquitoes.

When using an IGR feed-through product, horn fly control is long-term and preventive, not reactive. The IGR is ingested as part of the animal’s feed. Cattle then excrete manure that contains the IGR. Horn flies must lay their eggs in fresh manure, and the IGR keeps the horn fly pupae from developing into breeding, biting adult horn flies.

New this spring, MFA has two additional options for fly control in our Gold Star Mineral lineup. Ricochet and Ricochet FESQ Max are now available with Altosid IGR, providing all the features and benefits of these trusted mineral products along with feed-through horn fly control. Given expected intakes, the 0.01 percent level of s-methoprene is adequate for nearly all cattle.

Both are convenient, ready-to-use minerals formulated to balance year-long pasture feeding programs for beef cattle, and they do not require a Veterinary Feed Directive.

Begin to use MFA Gold Star fly control minerals in the spring before horn flies appear on cattle. Flies emerge when 14-day mean temperatures are 65 degrees and above. Continue feeding until cold weather stops fly activity. Make sure to feed IGR mineral throughout the season for a successful fly control program next year. If IGR feeding ends too early, there is a late-season increase in the adult population to lay eggs. The eggs over-winter and are ready to establish fly populations next spring. All that can be avoided by extending the feeding period of fly control minerals for 30 days after a killing frost to minimize the adult population and keep egg populations as low as possible.

Horn fly control with feed-through IGR is the easiest, most effective and economical way of controlling horn flies for cattle producers. To achieve optimum fly control, MFA Ricochet products with Altosid should be used in conjunction with other good management and sanitation practices. A number of integrated pest management resources are available online.

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Shrink happens

When humans are stressed, our bodies react with physical, mental and emotional responses. The same goes for beef calves that experience stressors such as hauling, handling or food and water deprivation. In cattle, these factors can lead to “shrink,” or weight loss that occurs from the time an animal leaves one location and is weighed at another.

The amount of shrink a calf experiences increases along with the number and duration of the stressors (see chart at right).

Managing shrink has implications on your calves’ health and profit potential, as demonstrated by a recent study by the University of Florida Institute of Food and Agricultural Sciences Extension. Shrink was measured in stocker calves after weaning in two separate years. The amount of shrink in one day amounted to 3.5 percent and 3.9 percent respectively, similar to the amount of shrink after eight hours of standing in a dry lot. In both years, calves did not regain their off-pasture weaning weight until day 14, even though they were offered high-quality hay and a pelleted supplement. The shrink was associated not only with a dietary change but also with handling, change in environment and tissue loss from stress.

In the second year of the study, the calves were also backgrounded for 50 days and transported 1,000 miles over 24 hours. These calves were unable to regain the lost body weight within 14 days, despite adequate access to hay, supplement and water. The amount of shrink increased because feed and water removal was coupled with the stress of transit.

How does shrink affect price? The appearance of calves at market can most certainly affect the bid. University of Arkansas data indicates that buyers adjust the price per pound based on an estimate of shrink to follow the purchase. Shrunk cattle received $3 to $8 greater sale prices compared to average fill calves. In contrast, calves that were full or very full were discounted $3 to $24 from the base selling price received by average fill calves.

Many different factors can affect shrink, but these have the most impact:

  • Transportation time: Studies show calves will shrink about 1 percent per hour for the first three to four hours, then 0.25 percent per hour for the next eight to 10 hours (e.g. 8 percent shrink in 16 hours).
  • Amount of fill: Diets low in dry matter and high in moisture result in a greater shrinkage, such as stockers on wheat pasture, whereas drier diets lead to slower weight loss and less shrink.
  • Body condition/weight: Typically, fatter cattle will not shrink as much as cattle with less body fat. Fat contains less water than lean muscle tissue, so lower amounts of metabolic- tissue water is lost to shrink.
  • Season: Higher temperatures induce a greater stress response in cattle and thus a greater shrink response. In hot weather, cattle lose more water through heavy breathing and greater maintenance energy expenditure than during cool temperatures.
  • Handling: Cattle shrink less when they are handled in a quiet manner using good Beef Quality Assurance practices.

Yes, shrink happens, but anything producers can do to minimize animal stress—and the resulting weight loss—protects the value of the calf when it is sold.

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Trace minerals are necessary minerals

It won’t show itself in highly visible ways like boosting daily gain, but keeping your herd, especially your cows, satisfied with needed trace minerals is an important job.

Mineral supplementation strategies should be formed based on several factors including forage mineral bioavailability, trace mineral interactions, stage of production and even breed.

A primary trace mineral deficiency is a relatively rare event in profitable beef cattle production. This type of deficiency would result if free-choice cattle mineral intakes were regulated below recommended feeding rates, or not fed at all. A secondary trace mineral deficiency may result when a properly balanced free-choice mineral is fed, but dietary or water-sourced minerals are not considered. In that case, a mineral antagonism can create a trace mineral deficiency. This is why water samples and periodic analyses of forages should be conducted annually.

Trace elements to watch are zinc, copper and manganese.

Zinc is involved in enzyme formulations via metabolism of protein and carbohydrates. It is also required to maintain the immune system. Zinc is necessary at a very basic level for efficient cell growth, and zinc deficiency can impact productivity and health.

Copper is necessary for a cow’s enzyme systems. It affects iron metabolism, the central nervous and immune systems. In the immune system, copper affects energy production and antioxidant enzyme production. It also affects the growth of antibodies and lymphocytes. As a result, copper can affect reproductive success.

Manganese serves as a cofactor in several enzyme systems, controlling hormone levels and release for optimal reproduction. Manganese also is required in mitochondrial superoxide dismutase, an enzyme that scavenges tissue-damaging free radicals.

Cows use the minerals they consume. Their tissue does not contain an unlimited supply. So effective mineral programs are important. They are especially important when you consider how a dam’s condition affects her offspring, something we often refer to as fetal programming.

During the last two months of gestation, a fetal calf grows at an exponential rate. During this time of rapid growth, it’s critical to have the building blocks of proper metabolism. Connective tissues and body organs require trace minerals for healthy development and must be retrieved from the dam’s blood supply. This is where bioavailable trace mineral supplementation can have its first economic impact on production.

For the beef producer, the critical period for supplying more bioavailable trace minerals to beef cows is from 60 days before calving through weaning. Not only does the cow benefit from better bioavailability, but calves consume free-choice mineral as well and added metabolic efficiency boosts the bottom line.

All MFA Gold Star free-choice minerals are formulated with “chelated” trace minerals. Amino acid chelates improve the bioavailability of trace minerals.

Research has shown feeding more bioavailable organic trace minerals has a favorable impact on bovine reproduction. These forms of minerals reduce the prevalence of early embryonic mortality (premature “death” of a fertilized embryo as a consequence of a failed implantation of the embryo within the endometrium of the uterus). These minerals also promote quicker uterine involution, fewer days to first estrus after calving and earlier conceptions. The uterine environment is healthier for improved reproductive efficiency when chelated minerals are fed.

When a beef herd starts on a chelated trace mineral program 60 days before calving, you tend to see heavier weaning weights in the first year. In addition, as more cows are settled earlier in the breeding season with less early embryonic mortality, weaning weights jump the second year as well.

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When it makes sense to supplement

There are several areas where supplement feeding will have the biggest profitability impact on a cow/calf operation. These scenarios are familiar to most of you. Your situation, herd health and goals will dictate how you approach them, but in general terms, they are:

Cows that are pre-calving through breeding

How you manage cow nutrition during gestation through breed-back is a critical time for your return on investment. Proper nutrition during this time helps dictate calf health and performance. It also has an impact on herd efficiency (and maybe a cow’s lifespan) by influencing her ability to reproduce. Mature cows should maintain at least BCS 5. Younger cows or heifers that are still growing need an extra half to full score of BCS. Consider a minimum of 2 pounds per day of Breeder Cubes, even when forage quality is excellent. Farms often have forage resources that cover the energy and protein requirements of mature cows, but from calving through breeding, the cows’ nutrient demands markedly increase due to milk production. Ensure adequate supplemental feeding to correct nutrient deficiencies.

Cows in the last 60 to 90 days before calving

The goal during this time is to keep cows from losing significant body condition and promoting fetal growth. Supplement feeding during this time helps the cow begin cycling increasing her chances to be bred early and subsequently calve earlier. Feeding Ricochet for at least 60 days before calving gives cows colostrum denser in antibodies for the calf. Better colostrum gets the calf off to a stronger start and increases the odds that it will survive and stay healthy.

Late gestation is also a critical time for fetal programming—a time when the nutrients received impact the calf’s vigor as well as its life-long health and performance.

During the summer

Mineral and vitamin delivery need to increase because of diminishing nutrient content in standing forage, especially toward fall when plants are busy sending nutrients to roots to overwinter. Typical forage programs will probably provide ample protein and energy to meet cow requirements when grazing improved summer pastures. It is mineral and vitamins that you need to watch. Supplementing with minerals and vitamins during this time prevents the need for the animals to deplete body stores of a limiting nutrient. Use a feed-through growth regulator for fly control, an excellent product to offer is MFA Ricochet Fesq Max CTC-ALT. Just keeping the flies off has been shown to increase animal performance.

Late summer and fall protein delivery

Maintaining body condition goes a long way toward improving cow performance. As forages mature at the end of summer and fall, appropriate protein supplementation can improve forage digestibility and intake. That helps cows maintain BCS. Cow weight gain response can be significant once calves are weaned off the cow. Even small amounts of protein can boost fermentation in the rumen to better process forage grazed from low-quality pasture.


A common thought in some parts of the Midwest is that we are always just a week away from a drought. Because you never know when the drought will arrive or when it will leave, you have to be flexible with supplementation plans. Get out in front by keeping your cows in the best shape you can. Concentrate on the best females and work you way down. Remember that once cows have been nutritionally stressed for long periods of time, they are more likely to suffer disease, nutrient imbalances and toxicities. Plan your cull strategy accordingly.

Creep feeding

Those calves represent your paycheck. A good weaning transition is important. Cattle Charge is a good choice for a creep feed as is Full Throttle. Using a creep feeding program will help in this transition process, add weight to the calf and help prepare calves for upcoming challenges and stress. Provide calves with the nutrients they need for developing optimal immune function to deal with stress and to start on feed from day one

Growing calves: replacement heifers and stockers

For growing cattle, a supplement delivery of a feed additive simply makes sense. The approximate 10 percent increase in average daily gains from the delivery of these additives in addition to the nutrients that are supplied in a supplement makes this an easy addition to the top-five list. Supplements can be formulated for lush growing pastures or can include protein as forages mature to meet the needs of developing heifers and stocker cattle.

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Veterinary Feed Directive Q&A

MFA Director of Animal Health Dr. Tony Martin has spent plenty of time on the road recently to answer questions about the upcoming implementation of the Veterinary Feed Directive. Here we highlight some of the top questions Dr. Martin took at producer meetings. The rule takes effect Jan. 1, 2017.

1. What will the cost of the VFD be to the producer?
Any cost or fee for the VFD will be at the discretion of the veterinarian who creates it. I have heard fees discussed ranging from nothing to over $100. The bottom line is that producers should expect some fee for the service. I tell producers not to consider the fee as a cost required to buy the document, but rather to consider it a fee for consultation. The real value of the VFD service comes from discussion between the veterinarian and producer about the need for antibiotics, which ones to use and how to best use them. These conversations will likely broach other topics about how producers might decrease or eliminate the need for antibiotic use. There could be room for improved vaccine protocols, environment, livestock handling, nutrition, genetics, etc.

2. How specific must information on the location of animals be for the VFD?
This question has been open to some interpretation. Some believe it has to be an official Premise ID. Some say just the owner’s address if the animals are on the owner’s property and nearby (say within a few hundred acres). Some say the location is a particular road address or coordinates for every building, pasture or facility where involved animals are located.
The commonly accepted answer from the FDA is that you need to provide the physical address where the treated animals are located. This will most often simply be the owner or manager’s address.

3. Do I need a separate VFD for each separate group of animals for the same claim?  In other words, will I need a separate VFD for cows grouped in different pastures for Anaplasmosis control? Similarly, would I need separate VFDs for multiple groups of incoming, commingled calves to receive standard pneumonia control protocol?
My interpretation is that a single VFD would fulfill the need for these examples. You would need to make sure that when you provide information for the VFD that you are giving an accurate approximation of the total number of animals. In the examples above, that would be the total numbers of cows in multiple pastures for anaplasmosis control or the total number of incoming calves to receive pneumonia control.

4. Can one VFD be used to purchase appropriate product from more than one distributor?
The feedback I have received from FDA indicates that this would be allowed—if the merchant locations are all under the same ownership and control (i.e. one company). I would add that the supplier needs to be within a reasonable distance of where the product will be administered per the VFD. In other words, if you have a VFD for animals on a northwest Missouri farm and file the VFD at a nearby MFA Agri Services, you probably ought not to use the same VFD for a farm you own in southeast Missouri where livestock is under someone else’s care. This might not be the case with an integrated production system, but I question if the same veterinarian-client-patient-relationship (VCPR) can apply to such broadly separated animals under private ownership.

5. If a producer is caring for animals owned by one or more absentee owners, does the caretaker/producer obtain the VFD or does each owner have responsibility for the VFD?
In this example, the caretaker/producer is caring for and treating the animals described on the VFD. The answer from FDA is that the VFD should list the caretaker/producer because that is the party most likely to have the VCPR with the veterinarian writing the VFD.

6. What about VFDs for rabbits or other minor species?
FDA is considering this issue but has yet to offer a final answer on the subject. The consideration includes allowing the use of a similar claim from a comparable species to be written as a VFD for a minor species. That idea carries with it some controversy as it would essentially be allowing Extra Label Drug Use (ELDU), which has always been illegal for feed additive medications.

7. Can a VFD be written for a feed antibiotic (tetracycline) for use to control or treat foot rot or pinkeye?
No. There are no feed additive antibiotics that have a legal use claim for use against foot rot or pinkeye. Chlortetracycline, the most commonly used antibiotic in such instances, only has feed use claims for anaplasmosis, bacterial enteritis, and bacterial pneumonia. Therefore, a VFD written listing the use claim for foot rot or pinkeye would be illegal and not allowed to be filled.

8. Many producers have heard that purchasing product from a valid VFD will have very specific limits concerning the amount of medication per pound or ton of feed with absolutely no overage allowed. Is that true?
According to FDA explanations, no. The use of the term “approximate” in the number of animals listed on the VFD form provides a level of flexibility in the amount of product that can be purchased.  Just as we do today, the VFD and conversations with veterinarians to get it provide an opportunity to discuss the amount of product actually needed and to discourage buying too much. From the perspective of the producer and the veterinarian, over-purchase makes no sense. Over-purchase can be poor management in the sense that you spend money on an excess product that might go out of condition or lose nutritional or medication effectiveness. From the veterinarian perspective, it risks feeding medicated product longer than needed or directed by the VFD and the legal requirement to quit feeding any remaining VFD product on hand after the VFD expires.  

9. There has been some concern from veterinarians and producers about VFDs requiring a specific grams-per-ton figure for the amount of medication allowed by the VFD. Will the gram-per-ton or pound-per-ton be specified on the VFD?
I contend that the VFD should be legal if it properly lists the legally claimed dose for a specific antibiotic in use claim given on the VFD. In most cases, that will be a figure of milligrams per pound of bodyweight or milligram per-head-per-day. That amount can be achieved through many different, legally approved medicated feed products (with varying grams-per-ton formulations). These formulations, when fed at the appropriate level per day, will accomplish the stated dosage stated on the VFD. For this reason, and given the fact that the VFD gives an “approximate” number and size to animals involved, grams-per-ton cannot be accurately and consistently given on a VFD without potentially creating severe restrictions on product choice and availability for the producer.

10. What “teeth” are written into the law? What repercussions will be enforced as the rule is launched?
The “teeth” are potential fines and, more importantly, the ability to designate treated animals as “adulterated” and prevent their sale or movement in the marketplace. But remember, the initial inspection effort will be to gather information about how the process is going and to educate producers and veterinarians.

11. Will VFD documents also be sent to the FDA? Will these VFD documents be subject to Freedom of Information requests?
The answer to both is no.

Kansas State University has a useful catalog of information on the VFD here:

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