Beef Cattle Browsing
Editor: Dr. Stephen Hammack, Professor & Extension Beef Cattle Specialist Emeritus
This newsletter is published by Texas AgriLife Extension – Animal Science. Media, feel free to use this information as needed and cite Texas A&M University Beef Cattle Browsing Newsletter, Dr. Steve Hammack.
SOUTHERN CALVES ARE SORRY
Not so, according to a study by Iowa State University and Certified Angus Beef ®. They evaluated records collected from 2002-07 on over 27,000 head in the Iowa Tri-County Steer Futurity. About two-thirds of the cattle originated in 10 Southeastern (SE) states and one-third in five Midwestern (MW) states. Initial weight, final weight, and ADG were similar, but the SE steers averaged 71 days younger. SE had less sickness, lower medical costs, and less death loss. USDA Quality Grade differed little. About 2% more black-hided SE calves met specifications for Certified Angus Beef ®. SE calves made $11.32/hd more profit. Considering these calves were enrolled in a special feed-out program, this may have been an above average sample of calves from the South. But the same was probably true of the Northern calves. At any rate, painting with a broad brush by calling all Southern cattle sorry, or at least not as good as those from the North, is certainly not supported by this study. (J. Animal Sci. 86, Suppl.1, Abstr. No. 18)
TREATING DRY BEEF COWS FOR MASTITIS
Oklahoma State University researchers used 197 spring-calving Angus and Angus X Hereford cows to study effects of intramammary antibiotic administration. At weaning, one-half of the cows received infusions into each udder quarter of penicillin G procaine and novobiocin. The other one-half of the cows were not treated. Milk samples were collected from all cows at weaning and again 8 to 14 days after calving and analyzed for somatic cell count. Calves were weighed at birth and every 30 days thereafter until weaning in October.
Treatment reduced the number of cows infected after calving, the number of cows developing new infections, and the number of infected udder quarters after calving that were infected at weaning. Among dams that were infected at the prior weaning, calves from treated dams averaged 44 lb heavier at 110 days of age. However, that difference did not exist at weaning (205 days of age). Among dams not infected at weaning, there was no difference due to treatment in 110-day calf weight. At weaning, the heaviest calves were from treated cows that were not infected at weaning the year before. The authors concluded that treatment reduced infection and increased calf weight gain. (J. Animal Sci. 86:748)
CARCASS QUALITY BONUSES HAVE DECREASED
The long-term average difference between USDA Choice and Select beef carcasses is about $8/cwt. For several months now, this difference has declined and even disappeared for short periods. In early June, Choice carcasses were priced about $3/cwt above Select, compared to about $9/cwt a year ago. There is an added bonus for high-quality branded programs such as Certified Angus Beef ®. A year ago, CAB was priced about $23/cwt above Select but currently that difference is about $10/cwt. One reason for the decline is that the percent of carcasses grading Choice has increased about 6% compared to last year. It may be that price differences are more sensitive to smaller changes in distribution of quality grades than might be thought.
PASTURE vs. DRYLOT BACKGROUNDING
Numerous research studies, field trials, and producer experience have shown the benefits of backgrounding calves for at least 45 days after weaning. New Mexico State University researchers wanted to compare two backgrounding management systems. Over three years, 250 steer and heifer calves (averaging 519 lb) out of British-crossbred dams were weaned about October 1 and for the next 42 to 45 days were placed on pasture (PS) or in drylot (DL). Pasture was central-New Mexico native range that had not been grazed the prior spring and summer. PS calves were supplemented with 32% CP cubes fed 3 lb/hd three times weekly. DL calves were started on 10 lb/hd/day of alfalfa hay and 5 lb/hd/day of a 16% CP pellet consisting largely of corn and wheat middlings. Pellet was gradually increased to 10 lb/hd/day by day 7 and hay reduced to 1.5-2.5 lb by day 13. All calves were weighed about midpoint through the backgrounding phase and at the conclusion. After backgrounding, all steers were moved to a finishing lot in northeastern New Mexico.
During backgrounding, PS gained more to mid-point but overall backgrounding gain favored DL. Total nutritional cost was $60.84 for DL and $11.91 for PS (including grazing fee). Net income during backgrounding was $15.72 for PS and a loss of $28.87 for DL. During finishing, PS gained more until re-implanting (74 to 94 days on feed) but overall gain to slaughter did not differ. Sickness and death loss was higher for DL. There were no differences in carcass characteristics. Total feed cost was slightly higher for PS, but overall feedyard cost did not differ. Net income was $103.01 higher for PS, at least partly due to differences in death loss. Post-weaning backgrounding can be an effective and profitable process, but nutritional cost in such programs is critical. (Prof. Anim. Sci. 24:169)
WHY DO CARCASSES FAIL TO MEET HIGH-QUALITY STANDARDS
Failure to meet standards and be accepted for high-quality branded-beef programs is primarily due to lack of marbling. But what factors are involved in acceptance rates? Certified Angus Beef ® examined their data on 21,350 head sired by Angus or predominantly-Angus bulls out of straight Angus or Angus-based cows. More heifers than steers qualified (34% vs. 25%). Cattle not implanted had 38% acceptance compared to 24% for implanted, and there was no difference between one, two, or three implants. Sorting cattle within a lot for slaughter increased acceptance; with three slaughter times acceptance was 34% compared to 30% for two times and 23% for one time. Lighter cattle going on feed had higher acceptance. Cattle with higher feed efficiency and lower cost of gain had lower acceptance. Factors not affecting acceptance included year, season, location, age, medicine cost, death rate, days on feed, average daily gain, and slaughter weight. The negative association between efficiency and acceptance is perhaps most problematic. (www.cabpartners.com)
Another study of CAB data including 11,645 head of “Angus-type cattle” identified other factors affecting acceptance rate in addition to the above. Fat cover tended to be higher as acceptance increased. The group with highest acceptance (> 30%) had smaller ribeyes. Cattle sired by Angus or predominantly-Angus bulls had higher acceptance than those sired by other or unknown breeds. (J. Animal Sci. 85, Suppl. 2, Abstr. No. 27)
GENETIC EFFECTS ON HEIFER REBREEDING
Culling first-calf heifers that don’t rebreed is often advanced as one tool to improve reproductive performance in a herd. If that practice is to improve a herd’s genetics for reproduction, there must be a genetic component involved in rebreeding. Montana State University and Colorado State University researchers investigated that question. They analyzed records on 417 females born over 19 years. Females involved were purebred Hereford, purebred Tarentaise, and crossbreds of varying percentage of those two breeds. Females were bred to calve first at two-years of age, only those calving at four were included in the analysis, and individuals were culled only if open in two successive years.
Overall rebreeding of two-year-olds was 72%. Depending on the method used for calculation, heritability of rebreeding was only 8%-14%. So, genetic progress from selection for rebreeding would be positive but very slow. However, culling heifers that don’t rebreed may improve production efficiency and economic returns even if genetics is not responsible for much of the benefit. (J. Animal Sci. 85, Suppl. 1, Abstr. No. 220)