Beef Cattle Browsing – November 2009

Beef Cattle Browsing

Editor: Dr. Stephen Hammack, Professor & Extension Beef Cattle Specialist Emeritus

November 2

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.

Lack of marbling has been identified as a problem in several National Beef Quality Audits. Price premiums for various high-quality marketing programs have led to increased genetic selection emphasis on marbling. How important overall is carcass quality in beef production? A recent symposium on “Balancing Live Cattle Performance and Beef Quality” provided some insight. In one paper, it was noted that “many data sets show that production parameters post weaning are two to three times more important than the value of the carcass.”

Another paper investigated “correlated responses and economic consequences to selection for increased marbling.” When selection was high for marbling, change in other traits was small. Also, in an integrated production system producing its own replacement females and retaining ownership through marketing on a carcass grid, selection for marbling resulted in little effect on net value. The authors attributed this to “lower importance of changes in marbling relative to other traits, including cow longevity and fertility.” So, while palatability is certainly needed to satisfy consumers, production traits remain paramount in the overall scheme of producing beef. (Univ. of Nebraska, University of Missouri; J. Animal Sci. 87, Suppl. 2, No. 230 and 232)

Records have been analyzed on Kansas cow-calf operations from 1979 to 2008. Over that 30-year period there was a positive return over variable costs (feed, fuel, repairs, veterinarian, etc.) in all but six of those years. Two extended periods were positive, 1986-1994 and 1999-2007. However, return over total costs (including depreciation, real estate taxes, unpaid family labor, and interest on assets) was positive in only four of those 30 years, including 2004 and 2005.

Herds were sorted into three groups based on return per cow over total cost from 2004 to 2008. Compared to the middle group, the high-return group had slightly lower weaning percentage and slightly higher weaning weight. Feed, interest, machinery, labor and other costs were notably lower. Veterinary, marketing/breeding, and depreciation cost did not differ much. Total cost in the high-return group was $110/cow less.

The low-return group had the lowest weaning percent, lowest weaning weight, and highest cost in every category except veterinary and marketing/breeding. Total cost in the low-return group was $287/cow higher than the high-return group. Similar results have been reported for Texas under the Standardized Performance Analysis system (SPA). (Kansas State Univ. Beef Tips, Nov. 2009)

Brahman X Angus calves were weaned at 80 days of age (EW) or 250 days of age (NW). EW grazed ryegrass pasture from January to May and limpograss pasture from May to August, with supplement at 1% of body weight of 80% soybean hulls: 20% cottonseed meal. Upon weaning, NW calves were placed on pasture for 45 days with EW. At that time, both groups were challenged with endotoxin. Based on blood analysis, EW showed higher levels of immune response. Other research has shown that fresh-weaned calves have lower immune response than backgrounded calves. Here, even compared to calves that were weaned for 45 days, early-weaned calves in this study had higher levels of immunity. (University of Florida, USDA-ARS; J. Animal Sci. 87:4167)

A survey was made of seven packing plants in Mexico. Approximately 90% of carcasses indicated features of strong Bos indicus genetics. Over 70% of cattle are slaughtered at live weights of 880 lb to 1100 lb. Almost 90% of carcasses weighed between 485 lb and 750 lb. Fat cover was less than 0.4 inch in 90% of carcasses. Over 70% of carcasses had ribeyes of less than 12.4 sq in and less than 10% had ribeyes over 14 sq in. Almost 94% had marbling scores of less than USDA Slight, the minimum for USDA Select. These findings shed some light on why Mexico is a good market for high-quality U. S. beef. (Universidad Nacional Autonoma de Mexico; J. Animal Sci. 87:3782)

Efficiency was measured in a group of 581 calves of six breedtypes: Angus (A), Brahman (B), 3/4A-1/4B, 5/8A-3/8B, 1/2A-1/2B, 1/4A-3/4B. Calves were weaned, preconditioned for 3 to 6 week, and then fed for 70 days with individual feed intake measured. Residual feed intake, RFI (difference between actual and expected intake), was calculated. As the fraction of Brahman increased the following tendencies were noted:

feed intake was lower,
weight gain was lower,
RFI increased (more efficient),
feed conversion ration increased (less efficient).

So, the effect of genetic type on efficiency depended on whether RFI or feed conversion was the measure. The authors noted this lack of agreement and indicated a need for further evaluation. (Univ. of Florida; J. Animal Sci. 87:3877)

Data were analyzed from 21 truckloads of calves averaging 102 calves/load and 463 lb/hd. Calves were placed in each of 8 compartments within the trailer and hauled approximately 675 miles. Calves were then backgrounded for an average of 47 days on a high-roughage ration. Calves in the nose top deck and nose bottom deck tended to be treated less for sickness. Those in the rear top deck had lower ADG. Calves in compartments with 15 head or fewer tended to be treated less than those in larger compartments. (Kansas State Univ.; J. Animal Sci. 87:4143)

Cows receiving protein supplementation on dormant Nebraska range were compared to unsupplemented cows. Compared to unsupplemented cows, heifer calves from cows receiving supplement had:

no difference in birth weight,
higher weaning weight,
higher weight at pregnancy determination,
higher weight at calving,
no difference in age at puberty,
higher percentage reaching puberty at breeding,
higher pregnancy rate.

Heifers from supplemented dams “appeared less feed efficient.” The authors noted that these findings provide “evidence of fetal programming response in female progeny to maternal nutrition.” (Univ. of Nebraska; J. Animal Sci. Supple 2, No. 8)

Angus, at about 334,000, continue to register by far the largest number of beef cattle in the U. S. (Holstein had slightly more registrations at last report). The remainder of the top 10 beef breeds were: Charolais (66,000), Hereford (64,000), Red Angus (48,000), Simmental (46,000), Gelbvieh (35,000), Brangus (30,000), Limousin (29,000), Shorthorn (16,000), Beefmaster (15,000). (National Pedigreed Livestock Council, 2009-10 Report)

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