Progress 07/01/99 to 06/30/04
Mature beef cows were used to measure long term effects of GI nematodes and bovine liver fluke. Stocker calves were used to evaluate anthelmintics and treatment strategies. Cows were treated for nematodes, flukes, both parasites or neither parasite. Untreated parasite infections did not significantly affect pregnancy rates. Untreated nematode infections reduced calf weaning weight. Parasite egg counts and infection rates were low for all groups. Two pour-on and two long-acting injectable formulations were evaluated on stocker calves and have been recommended for use.
These data demonstrate that the major loss to parasites in mature cows maintained on an adequate level of nutrition is a 20 to 30 pound reduction in calf weaning weight. The value of this loss will more than cover the cost of internal parasite control and should significantly improve net returns of cattle producers.
- Loyacano, A. F. 2003. Internal Parasite Control. LA Beef Forage Short Course Proceedings. Pp 12-15.
- Loyacano, A. F. 2003. Internal Parasite Control. Beef and Forage Field Day and Trade Show Proceedings. Vol. 4 .
- Williams, J. C. and A.F. Loyacano. 2001 Internal Parasites of Cattle in Louisiana and other Southern States. LSU Ag Center Research Information Sheet #104.
- Loyacano, A.F., J. C. Williams, J. Gurie. 2002. Effect of Internal Parasites on replacement Heifers. LA Cattleman. Pp 4.
- Loyacano, A.F. 2003. Internal Parasite Control. LA Beef Forage Short Course Proceedings. Pp12-15.
Progress 01/01/03 to 12/31/03
Five years data has been collected on the cow herd portion of this study and the data is being prepared for analysis. Raw data indicates that internal nematode parasites and liver flukes may not significantly affect mature beef cows when an adequate source of nutrition is available. Respective weaning weights and pregnancy rates for mature cows that received no anthelmintic treatments, were treated for G.I nematode, were treated for liver fluke or were treated for both parasites were 519 lbs. and 85%, 523 lbs. and 79%, 510 lbs. and 70% and 527 lbs. and 74%. It seems that these parasites have their most significant effects on first and second calf heifers. A second group of 90 steers is presently being grazed to determine the most effective and economical time to treat yearling steers for nematode parasites.
Purchasing and administering anthelmintics to control internal parasites is a major cost for cattle producers. Determining if treatments are economically beneficial and the most economically advantagous time to use them may significantly improve net returns of cattle producers.
- Loyacano, A. F. 2003. Internal Parasite Control. LA Beef Forage Short Course Proceedings. Pp 12-15.
- Loyacano,A. F. 2003. Internal Parasite Control. Proceedings - BEEF AND FORAGE FIELD DAY AND TRADE SHOW. Vol. Pp. 1-7.
Progress 01/01/02 to 12/31/02
Cow bodyweight, condition score and pregnancy rate and calf birth and weaning weight data are being collected on cows that are either being routinely treated for nematode parasites, liver fluke, both parastes or neither parasite. Cows are treated for nematodes in Aug. and Jan. and for fluke in Oct. and Jan. Three years data have been collected (cow observations = 327). The original cows in this project were in a heifer study with the same treatments and have received treatments for the same parasites since weaning. Replacements come from within the treatment groups and receive the same treatments as their dams. No significant treatment effects have been detected at this time. Three year averages for calf weaning weight and cow pregnancy rate are presented; TRT 1 612 lb. - 90%, TRT 2. 600 lb. - 92%, TRT 3. 609 lb. - 88%, TRT 4. 600lb. - 92%. Ninety home raised steers were used in anthelmintic evaluation trial that compared an experimental long acting injectable
formulation to two commercially available pour on formulations and an injectable combined anthelmintic/fluckicide formaulation. All treatments significantly reduced nematode egg counts for 28 days. Flukes were not a factor in this study. Total weight gains were not signifiantly different between treatment groups.
Essientially all beef cattle in our region are continulusly exposed to parasitic nematodes and many are exposed to liver fluke. Biannual treatment for these parasites is often reccomended. Treatment for these parasites is costly and time consuming. If the present study proves that these parasites generally do not negatively affect properly managed mature beef cows in this region, time and treatment costs can be saved.
- Loyacano, A. F., Williams, J. C., Gurie, J., and A. A. Derosa. 2002. Effect of gastrointestinal nematode and liver fluke infections on weight gain and performance of beef heifers. Vet. Parisitol, Vol 107(3):209-26.
- Loyacano, A. F., Williams, J. C. and J.Gurie. 2002.Effect of internal parasites on replacement heifers. The LA Cattleman, Oct.pp 4-5.
Progress 01/01/01 to 12/31/01
This project is being conducted to measure the effects of gastrointestinal nematodes and liver flukes on the production of mature beef cows. Cow body weight, condition score, pregnancy rate and calf birth and weaning weight data are being collected. Data have been collected for two years on cows (222 observations) that have been treated for either gastrointestinal nematodes, liver flukes, both parasites or neither parasite. Cows are being strategically treated for nematodes in August and January and for flukes in October and January. Treated cows were previously on a heifer study and have been on the same parasite treatments since weaning. Heifer data have been reported. Preliminary data from the cow study have not been analyzed. In a treatment evaluation study, 17 calves received no treatment for gastrointestinal nematodes and 41 calves received a subcutaneous injection of a long-acting avermectin. The treatment eliminated shedding of GI nematode eggs for up to 84
days in most treated animals. Animal gains were greater in treated animals.
Documenting the effects of internal parasites on mature cattle may allow producers to be more cost effective in or eliminate the cost of treating parasites in some categories of beef cattle. Evaluating new formulations of anthelmintics and comparing them to available products allows us to make recommendations to our clients.
- Williams, J. C. and Loyacano, A. F. 2001.Internal Parasites of Cattle in Louisiana and Other Southern States. Research Information Sheet #104. Louisiana Agricultural Experiment Station.
- Loyacano, A. F., Skogerboe, T.L, Williams, J. C., DeRosa, A. A., Gurie, J. A., Shostrom V. K. 2001. Effects of parenteral administration of doramenctin or a combination of ivermectin and clorsulon on control of gastrointestinal nematode and liver fluke infections and on growth performance in cattle. JAVMA, Vol 218, No 9. pp 1465-1468.
Progress 01/01/00 to 12/31/00
The objective of the cow phase of this study is to measure the effects of gastrointestinal nematodes and liver flukes on the production of mature beef cows. Cow body weight, condition score, pregnancy rate and calf birth and weaning weight data are being collected. Data for one year have been collected on 112 cows that have been treated for either gastrointestinal nematodes, liver flukes, both parasites, or neither parasite. Cows are being strategically treated for nematodes in August and January and for flukes in October and January. Treated cows were previously on the heifer phase of the study and have been on the same parasite treatments since weaning. Heifer data have been reported. Preliminary data from the cow study have not been analyzed. In the treatment evaluation phase of the project, a trial involving 120 calves evaluated three long-acting, injectable moxidectin formulations. All three formulations controlled nematode parasites for 150 days. Data from a
study involving 128 calves to measure the response of treated and untreated calves to humeral and CMI(cell mediated immunity) stimuli have not been analyzed.
Data from this project will allow producers to make sound management decisions about their parasite control programs and to select treatment products based on unbiased data rather than commercial advertisements.
- Loyacano, A. F., J. A. Gurie and J. C. Williams. 2000. Effect of internal parasites on replacement heifers. Dean Lee Research Station Annual Research Summary. pp 41-42.
- Loyacano, A. F., J. C. Williams, J. A. Gurie and Andy DeRosa.. 2000. Effect of internal parasites on replacement heifers. Louisiana Agriculture. Vol. 43, No.1., pp 20-21.
- Loyacano, A. F., J. C. Williams, J. A. Gurie and Andy DeRosa.. 2000. Internal parasite effects on beef heifers. Proc 45th Annual meeting, Am. Assoc. of Vet. Parasitologist. Abstr. 30.
- Loyacano, A. F. and J. A. Gurie. 2000. Effects of internal parasites on replacement heifers.Rosepine Research Station Field Day Proceedings. pp 3-6.
Progress 01/01/99 to 12/31/99
In the cow production phase of this project 112 cows that since weaning have been treated for either roundworms, liver flukes, both parasites or no internal parasites are being studied to determine the effect of the parasites on the reproductive performance and calf production of mature cows. In the anthelmintic evaluation phase of the project, 120 calves are being used to evaluate a new long acting injectable product and 132 calves are being used to study the effect of anthelmintic treatment on the immune systems of feeder calves.
Internal parasites cause significant losses to producers. Data from these trials allow them to make sound management decisions about when to treat for parasites and what products would be the most beneficial.
- Loyacano, A.F., J. C. Williams, J. A. Gurie, A. DeRosa, B. C. Clymer, and F. Guerino. 1999. A comparison of the persistent efficacy of the pour-on formulations of Moxidectin, Doramectin, Ivermectin and Eprinomectin when administered as a single treatment to stocker calves. Beef Cattle Research Report. 30:37-40.
- Loyacano, A.F., J. C. Williams and J. A. Gurie. 1999. An evaluation of the pour-on formulation of Dectomax. Beef Cattle Research Report. 30:41-42.