Beef Research News
Brought to you by Kansas State University
College of Veterinary Medicine - Farm Animal Section
November 2006
Contents:
Dam
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,
10.2527/jas.2006-337
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.
___________________________________________________________________
Beef Research News is produced by the Farm Animal section at
Kansas State University. To modify your subscription to this service
please email Erin Thomas (
ethomas@vet.k-state.edu )
For more information please contact:
Brad White
Beef Production Medicine
Q211 Mosier Hall
Manhattan, KS 66506
bwhite@vet.ksu.edu