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.
IS ORGANIC FOOD MORE NUTRITIONAL?
Not according to a recent review of research conducted at the London School of Hygiene & Tropical Medicine at the University of London. A search of the scientific literature from January 1, 1958 to February 29, 2008 found 162 studies where organic and conventional foods were directly compared. The report noted that “conventionally produced crops had a significantly higher content of nitrogen and organically produced crops had a significantly higher content of phosphorous and higher acidity” but there was “no evidence of a difference for eight other crop nutrients.” And the analysis “found no evidence of a difference in nutrient content between organically and conventionally produced livestock products.” (Am. Jour. Clinical Nutrition, July 29, 2009)
EFFECT OF BODY SIZE ON GRAZING BEHAVIOR AND ENERGY EXPENDED
Israeli researchers studied grazing behavior, diet intake, and energy cost of activity in two types of cows. Large crossbred Beefmaster-Simmental-Hereford cows averaged 1278 lb and small Israeli-native Saladi cows averaged 599 lb. The location of the experiment has a moderate Mediterranean climate averaging 22 in/yr precipitation, with almost none typically occurring from May to October. Cows of both types were grazed together, stocked at either 1.4 acres/cow or 2.8 acres/cow. Cows were supplemented with free-choice 25% CP dry poultry litter in autumn. GPS monitors attached to cows allowed measurement of activity, heart rate, and oxygen consumption.
The small cows had higher forage consumption per unit of metabolic weight (Wt 3/4) and they selected higher-quality forage in spring. Also, small cows averaged grazing 1.63 hours/day more and covered 35 percent more ground per day (2.74 miles versus 2.03 miles). Both types of cows grazed less and covered less ground as forage quality declined from spring to summer. When supplement was provided in autumn, grazing time and movement increased; this was attributed to increased forage digestibility due to the nitrogen supplied in the supplement. The authors noted that energy costs of physiological processes are similar in animals of differing size when based on metabolic weight. However, energy cost of movement is related to total weight, not metabolic weight. Therefore, movement requires relatively less energy for smaller animals. In conclusion, the authors determined that the smaller cows had advantages in efficiency of feed utilization and lower relative energy required for movement. (J. Animal Sci. 87:2719)
FACTORS AFFECTING FEEDING PERFORMANCE AND CARCASS MERIT
Data were analyzed on over 21,000 head fed in 18 southwest Iowa feedlots from 2002 to 2006 as part of the Tri-County Steer Carcass Futurity. Factors affecting outcome were reported as follows:
Disposition score: more excitable cattle had lighter weight (initial, final, and carcass), higher ADG, lower numerical Yield Grade (higher percent lean), higher marbling and Quality Grade, and greater death loss.
Respiratory sickness: higher sickness was related to lower weights, ADG, numerical Yield Grade, and marbling.
Initial weight: cattle that started heavier also had higher final and carcass weight; sickness was lower.
Initial Body Condition Score: cattle that started in higher body condition were heavier at the start but lighter at slaughter.
Respiratory disease treatment: as the number of treatments increased cattle had lower ADG, higher death loss, and more lung lesions.
Breed type: Continental types had heavier final and carcass weight, lower numerical Yield Grade, and lower marbling.
Muscling score: cattle with lower score had lighter carcass weight, smaller ribeye, higher numerical Yield Grade, lower marbling, and lower Quality Grade.
(Iowa State Univ., Kansas State Univ.; J. Animal Sci. 87:3030)
NATIONAL ID – THROUGH ANOTHER ROUTE?
Even though Congress voted earlier this year to stop funding the National Animal Identification System, there is some thinking within the livestock industry that identification could conceivably be implemented through other legislation. The Food Safety Enhancement Act of 2009 (HR 2749) is working its way through the legislative process. Among other things, the Act would charge the Secretary of Health and Human Services to require that “each person who produces, manufactures, processes, packs, transports, or holds a food” would have to “maintain the full pedigree of the origin and previous distribution history of the food, link that history with the distribution of the food, establish and maintain a system for tracing the food that is interoperable with the systems established and maintained by other such persons, and use a unique identifier for each facility owned or operated by such person for such purpose.”
There is no mention of precisely how identification of such traceback would be done or of how far traceback would extend. Note: this would deal with food safety (under FDA), not animal disease traceback (under USDA-NAIS). (http://www.govtrack.us/congress/billtext.xpd?bill=h111-2749)
EXTRUDED-EXPELLED COTTONSEED MEAL FOR BEEF COWS
Some processors are producing cottonseed meal using a mechanical extruding-expelling technique that involves higher heat than traditional methods. Higher temperature can affect rumen degradability and therefore feeding value. A study was designed to evaluate this product, using Angus and Angus X Hereford spring-calving cows initially averaging 1177 lb and 5.4 Body Condition Score (BCS). During the study, cows had access to minimal grazing but the bulk of forage consumed was free-choice 4.5% CP, 57% TDN tall-grass prairie hay.
Cows received one of three supplements at rates that provided the same amount of CP: solvent-extracted CSM (CSM), wheat mid-solvent CSM (WMCSM), or delinted extruded-expelled CSM (ECSM). There were significant differences among treatment groups in hay consumption with a cow of average initial weight (1177 lb) consuming as follows: ECSM = 23.9lb, WMCSM = 25.1 lb, CSM = 26.7lb. However, there were no significant differences among supplements in: change in body weight or BCS during supplementation, change in body weight or BCS from beginning of supplementation to calf weaning, calf birth weight, milk production, calf weaning weight, or pregnancy rate. (Oklahoma State Univ.; J. Animal Sci. 87:3003)
ANGUS-SIRED VS. WAGYU-SIRED CALVES
Angus cows produced 19 calves by Angus sires (AN) and 20 by Wagyu sires (WG). Calves were weaned at 138 days and fed a 65% whole corn ration to 1175 lb (heifers) or 1230 lb (steers). This required feeding AN 272 days versus 349 days for WG. For evaluation, carcasses were ribbed between the 12th-13th rib (US system) and the 6th-7th rib (Japanese system).
There were no significant differences in carcass weight, fat cover at the 12th rib, or Yield Grade. AN ate more and gained faster, but had lower feed efficiency. At the 12th rib, WG had higher marbling, resulting in USDA Quality Grade of 65% Prime and 35% Upper 2/3 Choice compared to 21 % Prime, 53% Upper 2/3 Choice, and 26% Lower 1/3 Choice for AN. AN had larger ribeyes at the 6th rib but WG tended to have larger at the 12th rib. There was no difference in tenderness whether aged 3 days or 14 days. WG produced higher-grading carcasses, but with no improvement in tenderness and at the expense of slower rate of gain and more days on feed to the same weight. (Ohio State Univ.; J. Animal Sci. 87:2971)
THE BATTLE GOES ON
More scare tactics and misinformation on the evils of modern food production, especially meat? Yes, and this time it’s the front cover story of TIME Magazine, August 21 http://www.time.com/time/health/article/0,8599,1917458,00.html . At the recent Texas A&M Beef Cattle Short Course, Alex Avery of the Hudson Institute presented documented evidence refuting the types of statements made in the TIME article. However, for every person who heard Avery there are many thousands who read high-circulation weeklies. And no doubt there was no TIME reporter in the Short Course audience. Even if there had been, would anything said there have been reported in TIME? It’s still an uphill battle.