LIVESTOCK AND CLIMATE CHANGE
Greenhouse gases (GHG) have been implicated by most, but not all, environmental scientists as the primary driver of climate change. GHG emissions from agriculture, and particularly livestock, have been claimed to cause anywhere from about 20%-50% of total emissions in the U.S. The latest report on GHG from the U.S. Environmental Protection Agency says otherwise. According to that report, in 2014 agriculture accounted for only 8.3% of total U. S. emissions. Of total emissions from agriculture, about one-fourth was from livestock, mostly from beef and dairy cattle.
[Inventory of U.S. Greenhouse Gas Emissions and Sinks:1990-2014 (April, 2016; https://www3.epa.gov/climatechange/ghgemissions/usinventoryreport.html ]
GENETIC EFFECTS ON CALVING DIFFICULTY
Data were analyzed from first-calf heifers of 10 breeds which have EPD for calving difficulty (Angus, Brangus, Charolais, Chiangus, Gelbvieh, Hereford, Limousin, Maine-Anjou, Red Angus, and Simmental). Heritability estimate for calving difficulty was higher for direct genetic effects (0.29) than for maternal genetic effects (0.13). Calving difficulty was lowest in calves sired by Angus, Brangus, Gelbvieh, and Hereford and highest from Charolais, Chiangus, and Limousin. However, maternal calving difficulty was lowest in Charolais, Limousin, Maine-Anjou, and Simmental dams and highest in Chiangus, Gelbvieh, and Red Angus.
(J. Animal Sci. 94:1857; U. S. Meat Animal Res. Ctr.)
EFFECT OF bST AT BREEDING ON REPRODUCTION AND CALF PERFORMANCE
Limited research in dairy cattle indicated administration of bovine somatotropin (bST) had some positive effects on reproduction. A group of 190 lactating Angus, Braford, and Brangus cows which had calved at least once were prepared with the 7-day CO-Synch + CIDR protocol for fixed-time artificial insemination (TAI). Cows were divided into four groups as follows:
- injected with saline solution at TAI and again with saline solution 14 days later;
- injected with 325 mg bST at TAI and with saline solution 14 days later;
- injected with saline solution at TAI and with 325 mg bST 14 days later;
- injected with 325 mg bST at TAI and again with 325 mg bST 14 days later.
Cows receiving bST had significantly higher levels of plasma IGF-1 (insulin-like growth factor 1, which promotes bone and tissue growth) for 14 days after injection. There was no significant effect on pregnancy rate, fetal growth 35 days or 65 days after TAI, or calf weight at 30, 60, 90, 120 or 150 days of age.
(J. Animal Sci. 94:2128; Virginia Poly. Inst. and St. Univ, Univ. of Florida, North Carolina St. Univ.)
EFFECT OF IMPLANT STRATEGIES ON PERFORMANCE AND CARCASS
A series of three trials was conducted to evaluate growth implant strategies. Exp. 1 included 1,405 heifers initially averaging 620 lb; Exp. 2 included 1,858 steers averaging 550 lb; Exp. 3 included 1,408 steers averaging 671 lb. In all three studies, initial implanting was with either a low-hormone level product (Revalor®-IH or IS), moderate level product (Revalor®-H or S), aggressive level product (Revalor®-200) or highly aggressive level product (Revalor®-XS). All were re-implanted using an aggressive or highly aggressive product.
In Exp. 1, there was no significant effect on feed consumption, ADG, feed efficiency, carcass weight, or ribeye area. Percent Choice quality grade was significantly higher when the initial implant was the low level.
In Exp. 2, there was no significant effect on feeding performance or carcass traits, except ribeye area was significantly larger from the aggressive and highly aggressive initial implants.
In Exp. 3, there was no significant effect on feeding performance, carcass weight, or marbling score. The combination of highly aggressive level initially followed by the aggressive level resulted in significantly larger ribeyes and less fat cover. Using either the aggressive level or highly aggressive level initially followed by the aggressive level resulted in significantly lower percent Choice.
The authors concluded “using greater initial-dose implant strategies may not affect gain or efficiency but appears to increase leanness”.
(Prof. Anim. Sci. 32:53; Univ. of Nebraska)
ADDITIVES FOR STOCKER STEERS ON WHEAT
A group of 365 steers initially averaging 536 lb was divided into three groups receiving free-choice mineral designed to supply either 1)200 mg/day monensin, Rumensin®, 2) 20 mg/day bambercycin, Gainpro®, or 3) no-additive control minerals. Overall ADG was: monensin = 3.01 lb; bambermycin = 2.79 lb; control = 2.73 lb.
(2016 Am. Soc. Am Sci. Southern Section Abst. 57; Univ. of Arkansas)
EFFECT OF CHRONOLOGICAL AGE AND CARCASS MATURITY ON EATING QUALITY
In order to allow export to some countries, carcasses of all cattle processed in federally inspected plants must be divided into classes of less than 30 months of age (MOA) or older, based on documented actual age or dentition. But once classified for age, carcass quality grade is affected only by visible skeletal and lean indicators of maturity (ranging from the youngest maturity, A, to oldest, E). Carcasses of increasing estimated maturity must have higher levels of marbling for a given quality grade.
A group of 600 carcasses was obtained from three processing plants, 300 each estimated by dentition to be either less than or over 30 months of age. Within each age class there were equal numbers of a combination of carcass maturity (A or B-D) and marbling (Slight, Small, or Modest-Moderate) categories, resulting in six groups. After 14 days of aging, strip loins were evaluated by a trained taste panel for tenderness, juiciness, and flavor and by mechanical shear force tenderness.
There was no significant difference in taste-panel tenderness, flavor, or juiciness or mechanical tenderness between carcass maturity groups in either dental age class, except that > 30 MOA had more intense grassy and bloody/serumy flavor and reduced tenderness in the Slight (U. S. Select) marbling group. Across all dental age/carcass maturity groups, increasing marbling was associated with improved taste panel and mechanical tenderness evaluations.
The authors concluded that skeletal ossification is an unreliable predictor of animal age, and that an alternative and perhaps more equitable approach for identifying carcasses of cattle for A maturity might be to consider age classifications rather than carcass maturity.
(J. Animal Sci. 94:2207; Colorado St. Univ.)
TEXAS A&M AGRILIFE EXTENSION GRASSFED BEEF CONFERENCE
The fifth Grassfed Beef Conference will be held on the campus of Texas A&M University on May 26-27, 2016. Topics to be addressed include:
- overview of the beef industry
- defining natural, grassfed, and organic
- fundamentals of growing forage
- cattle types suited for grassfed beef
- forage-based nutrition for cattle
- preventative herd health
- handling cattle for wholesome beef
- demonstration of carcass fabrication
- consumer expectations
- Taste of Texas Beef
- marketing a unique product
BQA (Beef Quality Assurance) TIP-OF-THE- MONTH : ANTIBIOTIC RESIDUES
When administering antibiotics make sure to calculate the proper dose based on the weight of the animal. Under dosing will likely reduce product efficacy and over-dosing increases withdrawal time and cost. If individual animals are treated with antibiotics, they should be individually identified and procedures should be put in place to prevent marketing before withdrawal times on the label or from your veterinarian are complete.