Beef Cattle Browsing
Editor: Dr. Stephen Hammack, Professor & Extension Beef Cattle Specialist Emeritus
February 2007
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.
WHAT’S HAPPENING TO ANGUS STOCKER/FEEDING PREMIUMS?
Getting higher the last few years, according to Certified Angus Beef. The CAB “Here’s the Premium Study” compiles data from cooperating auctions in California, Colorado, Kansas, Kentucky, Missouri, Montana, Nebraska, Oklahoma, South Dakota, and Wyoming. Data are collected in the Fall for 500 lb calves and in the Spring for 700 lb feeders. Each auction reports prices from a minimum of five groups, each containing at least five head. Data have now been reported on almost 237,000 head. From Spring, 1999, through Spring, 2003, premiums for Angus over Other Breeds ranged from a little less than $2.50/cwt to a little over $3.50. But things started changing in Fall, 2003. Since then, premiums have ranged from a little over $3.50 (for yearlings in Spring, 2004) to a little over $5.50 (for calves in Fall, 2005). As always, price premiums should be considered along with other factors affecting profit, especially any losses that might occur in performance and efficiency from lack of hybrid vigor. (CAB, Black Ink BasicsTM, Vol. 2, Issue 4)
ETHANOL FROM CORN – THERE’S SOMETHING LEFT TO FEED
Production of ethanol from corn continues to increase. This is causing some concern that there will be less corn for feeding, not to mention the elevating effects on corn price. However, there are byproduct feeds resulting from ethanol production, one of the most useful being distillers grains plus solubles (DGS), which is available wet (about 25-35% dry matter) and dry (about 90% DM). The dried product costs less to transport per unit of DM and can be stored for longer periods. Every bushel of corn yields about 17 lb of DGS.
How good is DGS as a cattle feed? Like many byproducts, the nutritional content varies but is usually, on DM basis, around 30% crude protein and 90-95% TDN compared to 9-10% CP and 88-92% TDN for corn. DGS is high in digestible fiber and low in starch. So, unlike high-starch sources like corn, DGS interferes less with utilization of forage, making it a good source for supplementing on low-quality forages. DGS is also high in bypass protein and fat (about 10-12%). The fat level should not interfere with forage utilization by grazing animals, but could be a problem in hay/silage programs where higher rates might be fed. Also, compared to corn, DGS is high in phosphorous and sulfur, so total ration levels of these minerals should be monitored. DGS should generally be limited to about 20% of total diet DM. So, while DGS offers real possibilities for cattle feed, there are limitations. We’ll still need corn, especially for finishing, and lots of it.
GENETIC EFFECTS OF FOLLICLE SIZE & PREGNANCY RATE
Heritability of pregnancy rate (PR) in cattle has generally been found to be low, so genetic improvement from selection of breeding stock is slow. Some research has shown a phenotypic relationship between ovulatory follicle size (FS) and PR. FS is a quantitative trait, so it could be potentially more useful in genetic selection than qualitative, all-or-none traits like PR. Researchers at the USDA Livestock and Range Research Laboratory in Miles City, MT, wanted to evaluate any genetic factors that might be involved in the relationship between PR and FS. They studied females from a stable composite population (consisting of 50% Red Angus, 25% Charolais, 25% Tarentaise) that had been developed at the Miles City station. Data were collected on 780 females, ranging in age from 1 to 12 years, over a four-year period. FS was determined by transrectal ultrasound shortly before artificial insemination. As has been found in many studies, heritability of PR was very low (0.07) and, unfortunately, that of FS was only slightly higher (0.16). In addition, genetic correlation between PR and FS was also low (0.08). The authors concluded that selection for FS “would produce essentially no correlated response” in PR, but that including both PR and FS in a selection index might be slightly more efficient in improving PR than by selection only on PR. (J. Animal Sci. 84:1646)
FACTORS AFFECTING CARCASS COMPOSITION
University of California researchers reviewed and analyzed results of 43 studies to assess effects of genetic type and growth implants on carcass traits. Eight breed-types were categorized as either early (EM) or late (LM) maturing. Implant status was implanted (IP) or non-implanted (NIP). At the same ribeye fat cover, LM produced significantly heavier carcasses with larger ribeye area than EM, but intramuscular and internal fat did not significantly differ. At the same live or carcass weight, LM had significantly larger ribeyes and less fat cover, intramuscular fat, and internal fat than EM. At the same weight, IP produced slight but not significantly larger ribeye than NIP. At heavier weights, IP had significantly less fat cover and internal fat. Regardless of weight, IP had lower intramuscular fat. As has been shown in numerous individual studies, this extensive review and analysis showed that later maturity and implanting resulted in heavier carcasses at the same fat cover. At the same weight, later maturity and implanting resulted in carcasses that were more muscular and with less external, internal, and intramuscular fat. (J. Animal Sci. 84:3143)
REDUCING VARIATION – THERE ARE LIMITS
We often hear that there is too much variation in the nation’s beef cattle herd. Compared to something like poultry or swine that’s undoubtedly true. But chickens and pigs are raised under much more uniform conditions than beef cattle, at least up to when cattle are weaned. The same kinds of cows don’t fit both the Upper Plains and the Gulf Coast. That’s not to say that we can’t reduce genetic variability, within limits. But let’s think about sources of variation we have little or no control over. Chickens can be marketed that are all hatched on the same day. But that’s not true for beef cattle. We sometimes hear that feeders would like start cattle with only a 50-pound range in weight. One of my associates, Dr. Ron Gill, recently reminded us of the variation in calf weight within a herd even with a narrow breeding season. Let’s say you have just a 45-day breeding season and your average weaning weights usually run 500-525 pounds. That means calves gain a little over 2 lb/day to weaning. So, even in a herd of high genetic uniformity, those calves will range at least 100 pounds at weaning, just from differences in the age of the calves. We should pay more attention to reducing variability. But we also should figure out ways to better manage the variability that is inherent in beef production.