Beef Cattle Browsing – July 2006

Beef Cattle Browsing

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

July 2006

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.

Missouri researchers evaluated prices of 2950 bred heifers in 929 lots sold through Show-Me-Select spring and fall sales from 2001 through 2004. Heifers in these sales must: be producer-raised or owned at least 60 days before breeding (with complete information on original breeder); conform to prescribed health and vaccination protocols; be dehorned and without scurs; have complete service-sire EPDs (with requirements on Birth Weight or Calving Ease), weigh at least 800 lb, be in BCS of 5 to 8, be evaluated for pelvic area and reproductive tract score, and be free of physical defects or undesirable disposition. Average price was $1080/hd (2005 average was $1349), average weight was 1033 lb, 36% of heifers were AI-sired, and 86% were Angus or Angus-cross. Factors significantly (P<.05) affecting price were: heifer weight; calf EPDs for Birth, Yearling, Milk, and Marbling; lot size; and position in the sale. Factors tending (P<.05 to .10) to affect price were: type of sire service; expected calving date; and calf Ribeye EPD. Buyers paid more for heavier heifers, sold in larger lots, and sold more toward the middle of the sale. Prices tended to be higher for heifers expected to calve earliest and those sired by AI. Heifers sold for more when their calves were predicted to have higher Birth, lower Yearling, lower Milk and  higher Marbling EPDs, and tended to pay more for higher calf Ribeye EPD. Heavier calf Weaning EPD positively, but not significantly, increased heifer price.

Average lot size was 3.13 heifers, with a maximum of 7 head. Average beef herd size in Missouri is 35 cows, so these sales appear to target average producers. Since such producers probably sell calves mostly at weaning and retain few heifers, it is not surprising that they did not pay more (and, in fact, paid less) for higher Yearling and Milk EPDs of their calves. These heifers were screened for factors contributing to calving difficulty (light body weight and small pelvic area), so buyers evidently felt that Birth EPD was not important. The authors stated, “This research found that quality developed heifers bred to sires with superior carcass quality genetics EPD demand premiums.” However, in view of the small average herd numbers in the state, the apparent targeting of such herds in these sales, and the high probability that these herds sell calves at weaning through traditional markets, it is difficult to see why such producers should emphasize carcass genetics. If such emphasis is being given it generally should not be, as there is likely little if any opportunity to be rewarded. (Prof. Anim. Sci. 22:217)

Arkansas researchers studied effects of treatment with progesterone via CIDR (controlled internal drug-releasing device) for seven days followed by prostaglandin administration. Compared to control cows, the treatment resulted in increased number of mounts, improved synchronization, higher first-service conception, decreased interval to first estrus, and possibly induction of estrous cycles in anestrous individuals. So, this method may offer benefits other than synchronizing heat. (J. Animal Sci. 84:1916)


Data continue to accumulate revealing the effect of sickness on fed cattle. New Mexico and Texas researchers analyzed four years of feedout data involving 813 steers, of which 22 percent were treated for sickness at least once. Animals were classified as never being treated (NT), treated once (T1), or treated two or more times (T2+). Compared to sick cattle (average of T1 and T2+), NT gained 0.28 lb/day more, cost of gain was $0.15/lb less, carcass value was $0.10/lb higher, and net income was $176/hd higher. Compared to T2+, T1 gained 0.24 lb/day more, cost of gain was $0.15/lb less, carcass value was $0.09/lb higher, and net income was $184 higher. (J. Animal Sci. 84:12, Supple. 1)

New Mexico researchers studied purebred Brangus heifers sired by three groups of sires: high Yearling EPD-low Scrotal Circumference EPD (HL); low Yearling-high SC (LH); and moderate Yearling-moderate SC (MM). LH-sired heifers were significantly lighter at both weaning and yearling. Postweaning ADG was not different. Postweaning, MM ate less feed daily and LH had poorer feed efficiency. At puberty, MM were 42 days younger and 71 lb lighter than LH and 54 days younger and 104 lb lighter than HL. Pregnancy percentages were: HL-71.4; LH-75.0; MM-87.5. It appears that, as in many things biological, moderation may be best. (Prof. Anim Sci. 22:48)

Six research studies out of Colorado, Indiana, Kansas, Mexico, Nebraska, and South Dakota examined effects of feeding ractopamine (Optaflexx®). Depending on the study, treatment was with 100, 200, or 300 mg/hd/day from 28 to 42 days before slaughter, and one study included stepping up levels every 14 days from 100 to 200 to 300 mg/day. In one study, there were no statistically significant differences between treated and control animals in feeding performance. In four studies ractopamine significantly increased weight gain, and tended to do so in another study. Feed efficiency was significantly improved in the three studies measuring that variable. There were no significant differences in any carcass characteristics, qualitative or compositional, in any study . (J. Animal Sci. 84:123-124, 220-222, Supple. 1)

Georgia researchers studied the effect of calving difficulty on subsequent conception rate (up to 90 days after calving) in field data from Canadian purebred Charolais herds. Calving was scored as no difficulty (1), some assistance or abnormal presentation (2), or hard pull or surgery (3). Compared to cows scoring 1, those scoring 2 were 3% less likely to conceive and those scoring 3 were 11% less likely. In addition to the adverse effects on calf survival, calving difficulty also impacts reproductive efficiency. (J. Animal Sci. 84:275, Supple. 1)

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