Effect of horn flies on milk production
A study was conducted on 53 spring-calving Brangus-crossbred cows. Horn fly counts and milk production estimates were recorded monthly from May through October on individual cows. Fly counts were lowest in May and highest in August. Higher fly counts were associated with lower milk yield and lower percent milk fat.

Milk yield was affected more by fly count in May-June (when cows were in early lactation and milking at highest levels) than in August-October. Higher fly counts decreased milk yield most in higher-milking cows. These results are perhaps another indication that adverse factors in the production environment, including horn flies, have greatest effect on higher-producing individuals. (J. Animal Sci. 92:1208; Univ. of Arkansas, USDA-ARS at El Reno, Ok.)

Relationship between instrument-evaluated marbling and palatability
Since 2006, instrument grading of beef carcasses has been approved by USDA. A study was conducted to assess how marbling estimated by instrument is related to eating characteristics. From four major packers located in Colorado, Kansas, Nebraska, and Texas, 718 steer and heifer carcasses were selected for evaluation.

All carcasses were A Maturity, which comprises the vast majority of carcasses submitted nationwide for USDA grading. Only about 1 percent each was of visibly apparent dairy type or Bos indicus influence. Approximately equal numbers of carcasses were included with the 7 degrees of marbling ranging from Traces (the level for USDA Standard) to Moderately Abundant (the level for mid-Prime).

About 70 percent of the carcasses were “A-stamp”, that is, identified at slaughter as ≥ 51 percent black hide, and therefore potentially qualified for Certified Angus Beef if carcass factors are acceptable.

From marbling degrees of Traces through Modest (mid-Choice) there was little difference in distribution of heifers and steers. However, from Moderate (high-Choice) to Moderately Abundant (mid-Prime), 60-70 percent of the carcasses were heifers.

About 50 percent of the carcasses with Traces marbling were A-stamp, but over 90 percent of carcasses with Moderately Abundant marbling were A-stamp. As level of marbling increased, fat cover tended to increase and rib-eye area decrease, therefore numerical Yield Grade increased (lean:fat ratio decreased). Carcass weight was not significantly different, except that carcasses with Traces were lighter.

Strip loin steaks were evaluated. As level of marbling increased, there was also increase in mechanically-evaluated tenderness and taste panel evaluation of juiciness, meaty/brothy flavor, and buttery/beef flavor. As marbling increased, bloody/scummy flavor, livery/organy flavor, and grassy flavor decreased.

Almost all (98-99 percent) of carcasses with marbling qualifying for Prime received positive ratings for overall sensory experience; others were upper 2/3 Choice = 80-90 percent, low Choice = 62 percent, Select = 29 percent, Standard = 15 percent. Overall, the authors concluded that instrument evaluation of marbling “effectively identifies subsequent differences in eating quality”, of broiled strip steak. (J. Animal Sci. 91:1024; Colorado St. Univ.)

Cow temperament vs. calf growth
A total of 380 cows in two herds were evaluated before calving for chute behavior and chute flight speed, and behavior when isolated. Shortly after calving, cows were scored for defensiveness when calves were ear tagged and when a cow-calf pair was isolated; calves were given a subjective vigor score. Calf ADG was measured to 7 months of age.

In one herd, temperament and defensiveness were unrelated; in the other, cows more nervous in the chute were more defensive. Across both herds, temperament and defensiveness were unrelated to calving ease or maternal behavior shown to the calf.

In one herd, cows more nervous in the chute had calves lighter at birth and calves from cows more agitated when isolated before calving had lower ADG. Defensiveness was not related to either calf ADG or vigor; pre-calving temperament was not related to calf vigor.

The authors concluded that “pre-calving temperament and post-calving defensiveness appear to be independent traits” but “fearful cows may produce calves with decreased birth weight and ADG." (J. Animal Sci. 91:4417; Anim and Vet. Sci. Group, SRUC, Scotland)

Does site of prostaglandin injection affect estrous synchronization?
Industry efforts have significantly reduced injection-site lesions in valuable beef cuts. This has been accomplished by making injections in the neck region, as outlined in Beef Quality Assurance programs. A group of 308 Angus multiparous crossbred cows in two herds were injected in either the neck or rump with prostaglandin, as part of either a standard or modified estrous synchronization program.

Site of injection did not significantly affect conception rate. Conception rate did not vary whether insemination was immediately after synchronization or 21 days later. The authors concluded that “location of injection did not change breeding or pregnancy rates” so “producers should follow BQA guidelines” when using estrous synchronization. (J. Animal Sci. 92 E-Supple 2:20; No. Carolina St. Univ., Ohio St. Univ., Pennsylvania St. Univ.)

Genetic/environmental interaction
If cattle do not perform the same in different environments, then genetic evaluations in one environment may not be universally useful. An analysis was conducted on records of birth and weaning weights (n = 74,681), postweaning gain (n = 39,104), and stayability (n = 28,895) from the American Red Angus Association.

Records were assigned to nine geographical regions of the U.S. (Corn Belt, Desert, Gulf Coast, Lower Plains, Mountains, Northeast, Pacific Northwest, South, and Upper Plains). Records were included only from sires with at least 50 calves and at least two regions.

Regional interactions were not important for birth weight, weaning weight, or postweaning gain. However, some notable interaction was found for stayability (probability of a female still being in the herd at 6 years of age). In general, interactions were lower for adjoining regions. The authors noted there was little interaction for growth traits, but “care should be taken when selecting sires to produce replacement heifers.”

NOTE: lack of genetic – environmental interaction means ranking of sires’ genetic potential for a trait should be similar across regions. It does not mean actual level of performance in different regions would necessarily be the same (and often would not be) because performance includes both genetic and environmental influences. (J. Animal Sci. 92 E-Supple. 1:9; Univ. of Missouri, Kansas St. Univ, Univ. of Zagreb, Croatia)

Value of certified pre-conditioned calves
The Oklahoma Quality Beef Network is a program designed to increase value of calves through improved health, general management, and marketing. Full details on requirements are available online. Data were collected on 11,927 calves at eight sales in the fall of 2013. Prices were compared for OBQN-certified calves and non-certified calves.

Average premium for certified calves was $8.65/cwt. Over the previous four years the yearly average ranged from $6.54 to $9.23. Premiums were generally, but not always, higher for lighter calves. Combining the higher price and additional weight gain, and subtracting cost of preconditioning, estimated additional return per head for certified calves was around $54 for 2013.

The authors of the report noted that any other variables possibly affecting price such as lot size, weight, breed, hide color, sex, fleshiness, and muscling were not considered in the analysis. (Oklahoma St. Univ. Cow/Calf Corner Newsletter, 3/03/14.)  

Dr. Stephen Hammack is professor and extension beef cattle specialist emeritus at Texas A&M University. This originally appeared in the Beef Cattle Browsing newsletter.