Beef Cattle Browsing is an electronic newsletter published by Texas A&M AgriLife Extension, Department of Animal Science at Texas A&M University. This newsletter is a free service and is available to anyone interested in beef cattle. Media, feel free to use this information as needed and cite Texas A&M University Beef Cattle Browsing Newsletter, Dr. Steve Hammack.
NEW RULES FOR TRACEABILITY, TRICH, AND FEVER TICKS
The Texas Animal Health Commission has released some amended regulations.
• TRACEABILITY – Within seven days of change of ownership within the state of Texas, any untagged adult (over 18 months) breeding cattle (including any placed on feed) must be permanently identified with an officially approved method, sent directly to slaughter, or resold at an auction market. This is not part of any specific disease control program and applies in all cases.
• TRICH – Untested adult bulls may be purchased without a current Trich test, if moved under TAHC permit with official permanent identification. Such bulls may also move from a market to a feedlot, to another market (for resale), or to another specified location. Permits will expire after a period of seven days, during which time there can be no commingling with female cattle. After seven days, bulls must be tested, resold at market, or delivered for slaughter.
• FEVER TICKS – New treatments have been approved for treatment of fever ticks and TAHC authority has been expanded to inspect and treat deer on premises adjacent to infected pastures.
More information can be accessed at www.tahc.state.tx.us/regs/code.html.
EFFECT OF MELOXICAM ON TRANSPORTATION STRESS
Meloxicam, a non-steroidal anti-inflammatory drug, has been shown to reduce stress associated with common management practices such as castration and dehorning. Transportation of cattle can create stress in varying degrees. A group of 97 Brahman and Angus × Brahman crossbred yearling steers, which had been backgrounded for 224 days, were blood sampled to establish baseline biological markers. Approximately one-half were given 15 mg meloxicam tablets at the rate of 1 mg meloxicam/kg body weight. The remainder was given placebo tablets. Cattle were then transported by truck 600 miles over 16 hours. Blood samples were taken on arrival and 5 days afterward.
The meloxicam treatment significantly decreased most biological markers of stress. Average body weight shrink during transport averaged approximately 8 percent, but was not significantly different for the two groups. There was no evaluation for any possible differences in health or performance. NOTE: Currently, meloxicam is cleared in the U. S. only for treatment of some pets.
(J. Animal Sci. 92:498; Iowa St. Univ., Mississippi St. Univ., Ohio St. Univ., Kansas St. Univ.)
CLIMATE CHANGE AND GLOBAL WARMING
The United Nations Intergovernmental Panel on Climate Change (IPCC) has reported that human activity is a factor responsible for global warming and resulting change in climate. A recent report by the Nongovernmental International Panel on Climate Change (NIPCC) also addresses this issue. This report documented research that was not included in the IPCC report. It also said the IPCC report contained information contrary to the IPCC’s conclusion that global warming results from human activity, rather than naturally occurring variation. The report included input from 27 scientists located at universities in 11 countries.
MULTIPLE-SIRE BREEDING GROUPS — WHAT HAPPENS?
Data were analyzed from three ranches, with fall and spring breeding seasons, and involving a total of approximately 2100 predominantly Angus females. Bulls were mostly Angus. Breeding seasons ranged from 70 to 120 days. Number of bulls per breeding group ranged from 2 to 9 with a ratio of 25 cows:1bull. All bulls passed Breeding Soundness Exams and young bulls were grouped. Bulls averaged 4.6 years of age, ranging from 1.3 to 11.6. Bulls determined to be injured on in poor condition were removed. Cows were assigned randomly to breeding groups. Paternity of calves was determined by DNA analysis.
Average number of calves per bull ranged little between ranches, years, or breeding seasons. Average number of calves in a breeding season was 18.9, but ranged from 0 to 64 for individual bulls. In 40% of the calf crops a bull produced only one calf. In 40% of the calf crops a sire produced 50 or more calves, and this advantage was concentrated in the first month of breeding. No calves were produced by 4% of the bulls. Scrotal Circumference EPD was positively related to calves per bull, but there was no significant relationship with 24 other EPD traits. Prolificacy of young bulls in their first year was positively related to subsequent years, but many bulls changed in prolificacy rank over breeding seasons. The authors recommended consideration of SC EPD in selecting yearling bulls, but acknowledged that prediction of prolificacy is problematic.
(Proceedings of Conference on Applied Reproductive Strategies, Staunton, Va., Oct. 2013; Univ. of California-Davis)
NUTRIENT RESTRICTION DURING EARLY AND MID GESTATION
A group of nonlacting, multiparous predominantly Angus cows initially averaging 1365 lb and 5.1 Body Condition Score were fed 8.1% CP grass/legume hay (starting at day 0 of pregnancy) to provide 100% of National Research Council (NRC) recommended energy levels for fetal growth. Then:
- starting on day 30 of pregnancy, part of the cows was reduced to 60% of NRC;
- starting on day 85, part of the 60% group was switched back to 100% NRC and part continued on 60% NRC:
- starting on day 140, all cows were on 100% NRC for the remainder of the study.
Results were as follows:
- on day 85, body weight was not significantly affected by energy level, fat cover was significantly lower in restricted cows, and their large intestine was significantly heavier;
- on day 140, cows restricted to 60% NRC throughout were significantly lighter in body weight (by 180 lb), rumen weight, and liver weight than those on 100% NRC throughout, while cows switched from 60% NRC back to 100% NRC were intermediate in those weights;
- by day 254, there were no significant differences in body weight, fat cover, or weight of any internal organs.
The authors concluded “it appears that the dam undergoes some adaptations during an early to mid gestation nutrient restriction and becomes more efficient in the utilization of nutrients after being realimented and as gestation advances”. NOTE: Reproduction and maternal performance was not part of this study. Other research has indicated that nutrition may be restricted to lower levels than previously thought required, without adverse effects on production in subsequent parities, as long as nutrition is adequate during late gestation.
(J. Animal Sci. 92: 520; No. Dakota St. Univ.)
EFFECT OF BODY MAINTENANCE ON LIFETIME REPRODUCTION AND SURVIVAL
Cattle are not mice. But at times some interesting mice research comes along that deals with the same types of traits important in cattle production. And research can be conducted on mice for many more generations than in cattle. A population of laboratory mice was divided into genetic selection lines as follows: high body maintenance (HM), low body maintenance (LM), and unselected controls (CT). Selection was implemented for 19 generations, relaxed for 26 generations (with lines continuing to be maintained separately), and then selection was resumed for another 9 generations. The lines were then compared for a number of reproductive and survival traits.
As stated in the report, “Overall reproductive performance was not substantially affected by changing maintenance requirements”. Mice from unselected control lines had higher lifetime number weaned, litter weight weaned, and offspring weaning weight. High maintenance had longer birth intervals. Controls always had higher probability of survival until next parity, except for very late in life when there was no difference. Compared to high maintenance, low maintenance had higher survival early in life, but this was reversed later in life. Therefore, the authors concluded with “genetic selection for low maintenance may be beneficial for systems desiring a short generation interval but less so for systems desiring longevity”. NOTE: Since unselected controls had higher overall survival and higher lifetime production, very long-term selection affecting maintenance may not be best.
(J. Animal Sci. 92:477; Univ. of Nebraska)
DO BETA AGONISTS AFFECT ALL MUSCLES THE SAME?
The beta agonists Optaflexx® and Zilmax® have generally been shown to increase lean yield, as well as feed efficiency and dressing percentage, with some reduction in marbling and tenderness. In a study involving approximately 4000 British X Continental steers, beta agonists increased ribeye area with no effect on fat cover. So, USDA Yield Grade was improved since the carcasses were more muscular. However, the authors reported “the majority of weight gain occurred in the lower priced cuts of the round and chuck”, so “increases in saleable yield were not uniformly distributed across the four major primals”. NOTE: Over the last year or so, price differences between the rib/loin and chuck/round have narrowed considerably.
(J. Animal Sci. 92:836; Colorado St. Univ.)
WHAT COUNTRIES EXPORT THE MOST BEEF?
Most people in the cattle business probably know that Brazil is a large exporter of beef, and that Australia and the U. S. probably rank high. We probably don’t even think of India, but it’s up in the top tier with those three. The next tier includes Argentina (which once exported much more than now) Belarus (perhaps surprisingly), Canada, the European Union, Mexico, New Zealand, Paraguay, and Uruguay. The exact rankings vary depending on their source. Of course, not all beef is the same. We are about the only country producing, and exporting, very much high-quality product while much of India’s is from water buffaloes.