Beef Research News
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nutrition effect on performance of heifer calves
Researchers conducted a 3-year study to evaluate heifer growth and reproduction as a result of dam nutritional management. The trial was organized in a 2 x 2 factorial to determine effect of late gestation (LG) or early lactation (EL) dam nutrition. The LG group was divided into no supplement (NS) grazing dormant Sandhills range or 0.45 kg/d of 42% CP supplement (PS). The EL group was fed either cool-season grass hay or grazed sub-irrigated meadow. Cows were managed as a single herd the remainder of the year. Dam nutrition did not impact birth date or birth weight of heifer calves. Feeding hay and NS decreased heifer 205-d weight when compared to meadow grazing and PS. Weight at pre-breeding was greater in heifers from PS dams. Pregnancy rates were greater for heifers from PS dams and a greater proportion of the heifers calved in the first 21 days of the first calving season. The research showed that protein supplementation (PS) in late gestation had long lasting effects compared to no supplementation. These findings provide evidence of fetal programming and the effect on heifer post-weaning reproductive and growth performance.
Martin, J.L., K. A. Vonnahme, D.
C. Adams, G. P. Lardy, and R. N. Funston
Effects of dam nutrition on growth and
reproductive performance of heifer calves J.
Anim Sci., Published Online first on Nov 3, 2006., DOI,
New instrument systems for marbling scores approved November 3, 2006, www.meatami.com
Two image-based instrument grading systems for the determination of beef carcass marbling scores for use in the evaluation of official USDA Quality Grades for Carcass Beef have been approved by the U.S. Department of Agriculture.
The two instruments approved for use are the VBS2000, manufactured by E+V Technology of Oranienburg, Germany, and the Computer Vision System, manufactured by RMS Research Management Systems of Fort Collins, Colo. Both systems were found appropriate for objectively predicting marbling scores accurately and precisely for use in the evaluation of beef carcasses for quality grade, certification programs and carcass data information programs.
Use of the systems as part of the official grading process is contingent upon users having a written plan approved by the Livestock and Seed Program to verify the instrument’s ongoing, in-plant operational accuracy as outlined in Phase III of the approval procedures for yield grading and PRIME II requirements for instrument marbling evaluation.
For additional information on the standards for the instrument grading of beef carcasses, visit http://www.ams.usda.gov/lsg/ls-st.htm
Effects of Animal Health on the Performance of Feedlot Cattle
There is a minimal amount of data available on the impact of disease on the performance of pens of fed-cattle. This study looks to quantify the effects of animal health on three performance measures: Feed conversion (FC), average daily gain (ADG), and cost of gain (COG). Multiple regressions were developed to analyze data and develop statistics for FC, ADG, added costs (AC), and percent mortality (MORT). The results that were obtained from these four models were then used to develop a COG spreadsheet. Irsik et al. concluded that for each percentage increase in death loss in a pen of cattle the FC ratio increased by 0.27lbs, ADG decreased by 0.08lbs per day and added costs increased $1.00 per head. For each percentage increase in treatments for a pen of cattle, death loss increased by 0.143%, therefore, a 10% treatment rate would result to a 1.7% death loss. Looking at opposite ends of the spectrum this study suggests that if no animals were treated, the FC ratio would be 6.34, ADG would be 3.32lbs and AC would be $22.86. Using the same model with all cattle receiving treatment, FC ratio would be 10.24, ADG would be 2.06 lbs and AC would be $37.51. These values would result in COG ranging from $50.13 per cwt. if no animals were treated to $86.55 per cwt. if all cattle were treated. This study confirms and quantifies the negative effect of adverse health on fed-cattle performance.
Irsik M, Langemeier M, Schroeder T, Spire M, Roder JD: Estimating the Effects of Animal Health on the Performance of Feedlot Cattle. Bov Pract 40: 65-74, 2006.
Advances in Management of Newly Received Feedlot Cattle
Bovine respiratory disease (BRD) is associated with losses in performance and carcass merit. The disease complex is the result of several viral/bacterial agents and Mannheimia haemolytica is the most frequently isolated organism. Preconditioning programs could have a significant influence on decreasing BRD. Diets with an increased energy concentration achieved by decreasing roughage concentration, may slightly increase the rate of BRD morbidity; however, these diets also increase ADG, DMI, and G:F compared with lower-energy, higher-roughage diets. Diets with high or low protein concentrations should probably be avoided, yet more research is necessary in this area. Performance effects resulting from supplementation of trace minerals (e.g. Cu, Se, Zn) known to affect immune function, have been equivocal. High levels of vitamin E supplementation (> 1,000 IU/animal/day) seems to reduce BRD morbidity, but has little performance effect. Newly received cattle should receive.
Duff, G.C. and M. L. Galyean
BOARD-INVITED REVIEW: Recent advances in
management of highly stressed, newly received feedlot cattle
J. Anim Sci., Published Online first on Nov 3, 2006., 10.2527/jas.2006-501
Environmental effects on Pregnancy rate in Beef Cattle
Effect of environmental conditions during the breeding season on pregnancy rate was quantified through examination of 10 years of calving records. Weather data from a local weather station was compiled including daily temperature and relative humidity. Minimum temperature (MNTP) and temperature-humidity index (THI) were compared to proportion of animals bred during 21 day increments of the breeding season. Both MNTP and THI were negatively associated with pregnancy rate for the first 21 and 42 days of the breeding season, with the most pronounced effect in the first 21 days. Reductions in pregnancy rate are likely when MNTP and THI equal or exceed 16.7oC and 72.9, respectively, during the breeding season.
Amundson, J.L., T.L. Mader, R.J.
Rasby, and Q.S. Hu. Environmental
effects on pregnancy rate in beef cattle. J.
Anim Sci. 2006; 84: 3415-3420.
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