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Economics of deworming beef cattle
Veterinary Parasitology, 27 (1988) 67-71 Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands
67
Economics of D e w o r m i n g B e e f Cattle ROBERTE. BOHLENDER
AnimaIClini~1603RodeoRoa~ North ~atte, NE ~ 0 1 ( ~ S . A . )
ABSTRACT Bohlender, R.E., 1988. Economics of deworming beef cattle. Vet. Parasitol., 27: 67-71. From the practitioner level and for the producer, there is far too much confusion concerning internal parasites in cattle and the justification of control measures. By coordinating research efforts between parasitologists and other scientists, awareness of internal parasites will be raised and the total impact of parasitism can better be evaluated.
I feel that veterinarians, animal scientists and producers are far too confused about deworming cattle and its economic impact. I practice in western Nebraska. My practice includes a lot of cow-calf along with backgrounding, yearling grazing and feedlot. My area includes the Sandhills (a unique tall grass area), some river bottom and some hardland with cropping and hard grass grazing. The area, in spite of this diversity, has no significant worm problems. Our cattle usually average 8-12 eggs per gram (e.p.g.) so when we get results with deworming it is due to 'Foo-Foo dust' and the 'moon phase'. I've been involved in a lot of research and field trial work including a number of controlled deworming field trials. We've had some remarkable results when proper timing and product selection was used. I assume the seasonal differences in products is in part due to Ostertagia. We have to make this assumption because we have very little knowledge about Ostertagia in our immediate area. In the early years we didn't look at enough criteria to evaluate properly the total economic impact. We were content just to look at the calf weaning weights on cow deworming. The cattle industry is undergoing some very dramatic changes and these changes will alter our needs in endoparasite control. Grazing management systems are changing to more short-term intensive grazing with rotation, which in my opinion will increase the potential of higher worm burden. The dramatic reduction in cow numbers has caused a change in cattle movement around the U.S.A. The abundance of cheap grazing has increased the 0304-4017/88/$03.50
© 1988 Elsevier Science Publishers B.V.
68 popularity of grassed yearlings. These yearlings are often shipped in from long distances. They represent numerous sources in one group and are a potential for new worm exposure. Severe economic stress in the industry is causing producers to alter marketing and feeding programs. T h e y are also very critical of all expenses and require good cost-benefit data for any procedure. Most poor producers have gone in our part of the country and the survivors are much more sophisticated businessmen. Specialization is increasing, with the concentration of larger numbers of cattle, often from a wide range of sources. Feedlots of over 50 000 head are common and can result in a wide array of problems. We also see more problems arising from a dramatic increase in individual productivity. Possibly we have overdone individual performance without paying enough attention to the increased nutritional demands and biological stresses. These cattle are much more susceptible to the adverse effect of worms. In our area, the large cow has problems every year. During a severe winter or a poor grass summer the problems are exacerbated. The conception rates on these cows can be terrible. We see groups of high percentage exotic cows run 80% open as opposed to 15% open in the British breed cows in the same herd. We have also emphasized high milk production which has the same effect. In one field trial we evaluated baby calf viability following a cold winter and saw statistically significant calf mortality at calving time in the calves of the unwormed cows. We also had a lot of cows t h a t required special feeding in the unwormed group. We would have had quite a death loss had these cows not been given special attention and feed. T h e y did not have the clinical symptoms of worms, they were just thin and a few were down and responded to calcium IV. I think t h a t a lot of parasitologists are missing the boat in their research. We need much more information on the disease predisposition factors involved with various worms. To a number of us in the National Cattlemens' Association, this is a very important approach to disease research. Mixed infections are the rule rather t h a n the exception. Based on this idea I have initiated research t h a t has resulted in the isolation of several viruses t h a t were responsible for bacterial disease (specifically, Rota, Corona and BRSV). In several field trials I have seen control of clinical coccidiosis with deworming. In one field trial using deworming at prewean time we saw a 30 lb. advantage over the controls in 60 days. This occurred in a herd with 8 e.p.g. The controls did not have any significant clinical disease problems so we surely had some effect on subclinical disease problems. In other field trials we had all of the calf mortality during the summer grazing in the unwormed controls. During the 1950s, Australian research apparently demonstrated t h a t there were more worms in copper-deficient animals t h a n in their copper-supple-
69 mented mates. Why didn't you people follow up on this? I feel that this is an excellent example of the problems of professional territorialism; parasitologists should be part of a lot more research efforts. We are interested in the effect of micronutrients on the immune system and cellular alterations. What is the effect of a micronutrient imbalance for the wintering cow and her ability to handle a worm burden? Also, what does the imbalance do to the reproduction of the worms? I think we feed to an imbalance with grass hay that has high levels of molybdenum that creates a copper deficiency. If this happens do we have a seasonal immune suppression? Does this explain some of the excellent results I see with deworming? If so, we need to investigate it because these imbalances are very common in the U.S. There is some indication that the Fesque endophyte problem may also result in imbalances. The developing research at Kentucky needs parasitology input. Can you imagine the influence on the timing of anthelmintic use? We see copper-deficient cows that have calves with a laboratory-diagnosed nitrate problem. These cows had no access to high nitrate feed or water and had no clinical problems. What does this situation do in the face of a worm burden, especially with inhibited Ostertagia? In The National Cattlemens' Association we have developed policy and priorities asking for an integrated approach to disease research. We are serious about this effort. The Roman L. Hruska Meat Animal Research Center is developing a disease research unit along the lines of multidisciplinary efforts. They will have to have parasitology as one discipline to conduct the type of research that we request. I serve on the National Animal Health Science Research Advisory Board. When I presented the NCA policy and priorities to the Board, the concept was accepted and will influence the Formula and Competitive Grants. One of your group, Dr. John Nielson of Florida, also serves on this Board. Dr. Gary Zimmerman developed a resolution for the USAHA committee on parasites and parasiticides. It asked for involvement of parasitology in integrated disease research. It was easy for me to speak in support of the resolution and it carried unanimously. I commend the efforts that some of you make to position your discipline for visibility and the resulting funding that will result. Now if you people will look past the old-style single entity, single discipline approach to research you can really involve parasitology in its proper perspective. That being that parasites, especially one as complex as Ostertagia, are one contributing factor in many disease problems. At a time when I'm fine-tuning the health program for many of my clients it seems like I'm fumbling around with parasite control. I really envy the information Dr. Bob Corwin has developed for Missouri with a strategic plan. How much of this information can I interpolate to western Nebraska? I have enough trouble trying to justify and implement cost-effective deworming pro-
70 grams between producers in my own area without having to try to judge data from other areas of different climate and production systems. For years I was told by all the local experts and then by the southerners (who think they have a monopoly on worms) that deworming in my area was not cost effective. At a meeting in one state I heard that they could only justify deworming on a wet year. Our average precipitation is about 20 inches, way under their dry ones. This e.p.g, criteria for justifying deworming really bugs me. About 15-18 years ago we ran e.p.g, counts once a month for two summers on cattle on range and irrigated pastures to see what the e.p.g, level was and if it was altered by cattle concentration seasonally and from year to year. We never saw any change that was significant and so we didn't deworm. Now we deworm certain cattle on part of these same operations with good proven results. Years ago, when the feeders in our area who dewormed dirty southern cattle and the questionable western cattle dewormed our local clean cattle they got good results. We had always been told that we didn't have worms in our cattle. At that point we looked at cow deworming and got 15 lbs. weaning weight increase. They got 25 lbs. at the Meat Animal Research Center. These were large well-run projects with good numbers of controls. In our field trials we've had a 7-11% conception increase, or 40 lbs. weaning weight, with both cow and calf deworming, or reduced calf mortality at calving, or 30 lb. increase in preweaning to postweaning in 60 days, or reduced suckling calf and weaning calf mortality, or cow weight increase, and lowered calving to breeding interval. All this has been done in herds that regularly run e.p.g, counts of from 8 to 12. Yet my clients continually read that you should run e.p.g, counts before you spend money on dewormers. An animal scientist at the University of Nebraska says that 200 e.p.g, is a good criteria. ( H e ' s not an ordained parasitologist. ) Now you can understand some of my frustrations with people telling me what I can't do with my scales. A P H I S has initiated a program that was initially called the National Animal Disease Detection System ( N A D D S ) that is now named the National Animal Health Monitoring System ( N A H M S ) . It is being developed under the leadership of Dr. Lonnie King. This program has the ability to evaluate subclinical disease and hopefully will bring out the losses due to internal parasites. I would encourage you to input into this program if you have the opportunity. I serve on the work group helping to develop the system and have been very impressed with the potential that it offers. One last item that I would like to mention is the Beef Safety Assurance Program that we are working on at NCA. The erosion of consumer confidence
71 in beef due to a perception that the chemicals in beef are hazardous is a serious situation. We must be very careful in the use of drugs, including anthelmintics. We must use only approved products and use them only in the prescribed manner. We should separate anthelmintics from pesticides. Pesticides are under the jurisdiction of EPA, while anthelmintics are under FDA. You people in parasitology need to make yourselves more available to the cattle industry. You can best do this at the state level by joining the state cattle association as an associate member and attending a few meetings. Offer to be on their programs and counsel them about parasites. Often if you wait to be asked, they don't even know you or enough about your discipline to ever ask. At NCA we actually have more policy regarding parasites than any other area in animal health. However, most of it concerns ectoparasitism and a portion of this is because we have had more entomologists solicit support at conventions. Dan Childs of Lake Placid, Florida, is the newly appointed chairman of the Parasite Subcommittee. I'm sure he would appreciate input from any of you on pertinent topics. Dr. Bob Corwin will represent AAVP at the NCA convention in Reno, Nevada, in January 1987. During the last year, since I presented this paper, I have found significant differences:inrespiratory disease control by adding deworming to prewean processing. It is obvious to me that worms suppress the immune system sufficiently to lower the response to vaccines and to infections such as coccidia and respiratory disease.
67
Economics of D e w o r m i n g B e e f Cattle ROBERTE. BOHLENDER
AnimaIClini~1603RodeoRoa~ North ~atte, NE ~ 0 1 ( ~ S . A . )
ABSTRACT Bohlender, R.E., 1988. Economics of deworming beef cattle. Vet. Parasitol., 27: 67-71. From the practitioner level and for the producer, there is far too much confusion concerning internal parasites in cattle and the justification of control measures. By coordinating research efforts between parasitologists and other scientists, awareness of internal parasites will be raised and the total impact of parasitism can better be evaluated.
I feel that veterinarians, animal scientists and producers are far too confused about deworming cattle and its economic impact. I practice in western Nebraska. My practice includes a lot of cow-calf along with backgrounding, yearling grazing and feedlot. My area includes the Sandhills (a unique tall grass area), some river bottom and some hardland with cropping and hard grass grazing. The area, in spite of this diversity, has no significant worm problems. Our cattle usually average 8-12 eggs per gram (e.p.g.) so when we get results with deworming it is due to 'Foo-Foo dust' and the 'moon phase'. I've been involved in a lot of research and field trial work including a number of controlled deworming field trials. We've had some remarkable results when proper timing and product selection was used. I assume the seasonal differences in products is in part due to Ostertagia. We have to make this assumption because we have very little knowledge about Ostertagia in our immediate area. In the early years we didn't look at enough criteria to evaluate properly the total economic impact. We were content just to look at the calf weaning weights on cow deworming. The cattle industry is undergoing some very dramatic changes and these changes will alter our needs in endoparasite control. Grazing management systems are changing to more short-term intensive grazing with rotation, which in my opinion will increase the potential of higher worm burden. The dramatic reduction in cow numbers has caused a change in cattle movement around the U.S.A. The abundance of cheap grazing has increased the 0304-4017/88/$03.50
© 1988 Elsevier Science Publishers B.V.
68 popularity of grassed yearlings. These yearlings are often shipped in from long distances. They represent numerous sources in one group and are a potential for new worm exposure. Severe economic stress in the industry is causing producers to alter marketing and feeding programs. T h e y are also very critical of all expenses and require good cost-benefit data for any procedure. Most poor producers have gone in our part of the country and the survivors are much more sophisticated businessmen. Specialization is increasing, with the concentration of larger numbers of cattle, often from a wide range of sources. Feedlots of over 50 000 head are common and can result in a wide array of problems. We also see more problems arising from a dramatic increase in individual productivity. Possibly we have overdone individual performance without paying enough attention to the increased nutritional demands and biological stresses. These cattle are much more susceptible to the adverse effect of worms. In our area, the large cow has problems every year. During a severe winter or a poor grass summer the problems are exacerbated. The conception rates on these cows can be terrible. We see groups of high percentage exotic cows run 80% open as opposed to 15% open in the British breed cows in the same herd. We have also emphasized high milk production which has the same effect. In one field trial we evaluated baby calf viability following a cold winter and saw statistically significant calf mortality at calving time in the calves of the unwormed cows. We also had a lot of cows t h a t required special feeding in the unwormed group. We would have had quite a death loss had these cows not been given special attention and feed. T h e y did not have the clinical symptoms of worms, they were just thin and a few were down and responded to calcium IV. I think t h a t a lot of parasitologists are missing the boat in their research. We need much more information on the disease predisposition factors involved with various worms. To a number of us in the National Cattlemens' Association, this is a very important approach to disease research. Mixed infections are the rule rather t h a n the exception. Based on this idea I have initiated research t h a t has resulted in the isolation of several viruses t h a t were responsible for bacterial disease (specifically, Rota, Corona and BRSV). In several field trials I have seen control of clinical coccidiosis with deworming. In one field trial using deworming at prewean time we saw a 30 lb. advantage over the controls in 60 days. This occurred in a herd with 8 e.p.g. The controls did not have any significant clinical disease problems so we surely had some effect on subclinical disease problems. In other field trials we had all of the calf mortality during the summer grazing in the unwormed controls. During the 1950s, Australian research apparently demonstrated t h a t there were more worms in copper-deficient animals t h a n in their copper-supple-
69 mented mates. Why didn't you people follow up on this? I feel that this is an excellent example of the problems of professional territorialism; parasitologists should be part of a lot more research efforts. We are interested in the effect of micronutrients on the immune system and cellular alterations. What is the effect of a micronutrient imbalance for the wintering cow and her ability to handle a worm burden? Also, what does the imbalance do to the reproduction of the worms? I think we feed to an imbalance with grass hay that has high levels of molybdenum that creates a copper deficiency. If this happens do we have a seasonal immune suppression? Does this explain some of the excellent results I see with deworming? If so, we need to investigate it because these imbalances are very common in the U.S. There is some indication that the Fesque endophyte problem may also result in imbalances. The developing research at Kentucky needs parasitology input. Can you imagine the influence on the timing of anthelmintic use? We see copper-deficient cows that have calves with a laboratory-diagnosed nitrate problem. These cows had no access to high nitrate feed or water and had no clinical problems. What does this situation do in the face of a worm burden, especially with inhibited Ostertagia? In The National Cattlemens' Association we have developed policy and priorities asking for an integrated approach to disease research. We are serious about this effort. The Roman L. Hruska Meat Animal Research Center is developing a disease research unit along the lines of multidisciplinary efforts. They will have to have parasitology as one discipline to conduct the type of research that we request. I serve on the National Animal Health Science Research Advisory Board. When I presented the NCA policy and priorities to the Board, the concept was accepted and will influence the Formula and Competitive Grants. One of your group, Dr. John Nielson of Florida, also serves on this Board. Dr. Gary Zimmerman developed a resolution for the USAHA committee on parasites and parasiticides. It asked for involvement of parasitology in integrated disease research. It was easy for me to speak in support of the resolution and it carried unanimously. I commend the efforts that some of you make to position your discipline for visibility and the resulting funding that will result. Now if you people will look past the old-style single entity, single discipline approach to research you can really involve parasitology in its proper perspective. That being that parasites, especially one as complex as Ostertagia, are one contributing factor in many disease problems. At a time when I'm fine-tuning the health program for many of my clients it seems like I'm fumbling around with parasite control. I really envy the information Dr. Bob Corwin has developed for Missouri with a strategic plan. How much of this information can I interpolate to western Nebraska? I have enough trouble trying to justify and implement cost-effective deworming pro-
70 grams between producers in my own area without having to try to judge data from other areas of different climate and production systems. For years I was told by all the local experts and then by the southerners (who think they have a monopoly on worms) that deworming in my area was not cost effective. At a meeting in one state I heard that they could only justify deworming on a wet year. Our average precipitation is about 20 inches, way under their dry ones. This e.p.g, criteria for justifying deworming really bugs me. About 15-18 years ago we ran e.p.g, counts once a month for two summers on cattle on range and irrigated pastures to see what the e.p.g, level was and if it was altered by cattle concentration seasonally and from year to year. We never saw any change that was significant and so we didn't deworm. Now we deworm certain cattle on part of these same operations with good proven results. Years ago, when the feeders in our area who dewormed dirty southern cattle and the questionable western cattle dewormed our local clean cattle they got good results. We had always been told that we didn't have worms in our cattle. At that point we looked at cow deworming and got 15 lbs. weaning weight increase. They got 25 lbs. at the Meat Animal Research Center. These were large well-run projects with good numbers of controls. In our field trials we've had a 7-11% conception increase, or 40 lbs. weaning weight, with both cow and calf deworming, or reduced calf mortality at calving, or 30 lb. increase in preweaning to postweaning in 60 days, or reduced suckling calf and weaning calf mortality, or cow weight increase, and lowered calving to breeding interval. All this has been done in herds that regularly run e.p.g, counts of from 8 to 12. Yet my clients continually read that you should run e.p.g, counts before you spend money on dewormers. An animal scientist at the University of Nebraska says that 200 e.p.g, is a good criteria. ( H e ' s not an ordained parasitologist. ) Now you can understand some of my frustrations with people telling me what I can't do with my scales. A P H I S has initiated a program that was initially called the National Animal Disease Detection System ( N A D D S ) that is now named the National Animal Health Monitoring System ( N A H M S ) . It is being developed under the leadership of Dr. Lonnie King. This program has the ability to evaluate subclinical disease and hopefully will bring out the losses due to internal parasites. I would encourage you to input into this program if you have the opportunity. I serve on the work group helping to develop the system and have been very impressed with the potential that it offers. One last item that I would like to mention is the Beef Safety Assurance Program that we are working on at NCA. The erosion of consumer confidence
71 in beef due to a perception that the chemicals in beef are hazardous is a serious situation. We must be very careful in the use of drugs, including anthelmintics. We must use only approved products and use them only in the prescribed manner. We should separate anthelmintics from pesticides. Pesticides are under the jurisdiction of EPA, while anthelmintics are under FDA. You people in parasitology need to make yourselves more available to the cattle industry. You can best do this at the state level by joining the state cattle association as an associate member and attending a few meetings. Offer to be on their programs and counsel them about parasites. Often if you wait to be asked, they don't even know you or enough about your discipline to ever ask. At NCA we actually have more policy regarding parasites than any other area in animal health. However, most of it concerns ectoparasitism and a portion of this is because we have had more entomologists solicit support at conventions. Dan Childs of Lake Placid, Florida, is the newly appointed chairman of the Parasite Subcommittee. I'm sure he would appreciate input from any of you on pertinent topics. Dr. Bob Corwin will represent AAVP at the NCA convention in Reno, Nevada, in January 1987. During the last year, since I presented this paper, I have found significant differences:inrespiratory disease control by adding deworming to prewean processing. It is obvious to me that worms suppress the immune system sufficiently to lower the response to vaccines and to infections such as coccidia and respiratory disease.