Beef Cattle Browsing – July 2009

Beef Cattle Browsing

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

July 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.

Not according to a recently published study of over 120,000 women. There was no increased risk of developing breast cancer due to total meat intake, red meat intake, meat cooked at high temperatures, or meat mutagens. (Albert Einstein College of Medicine and National Cancer Institute; Int. J. Cancer: 124:2430)

Angus and Hereford cows were bred to Brahman, Boran (an east African Bos indicus breed similar in appearance to but smaller than Brahman), and Tuli (a Bos indicus-Bos taurus combination African breed) to produce F1 females, which were then evaluated from 1994 to 2006. The study included from 1090 to 1474 records collected on 143 cows. Results were as follows:

Birth Wt, lb 77.2 76.6 76.8
Weaning Wt, lb 519 486 458
Calf crop born, % 88.1 93.1 89.0
Calf crop weaned, % 84.8 89.8 86.9
Cow Wt, lb 1322 1131 1129
Cow BCS, units 5.23 5.48 5.18
Mouth soundness (’04-’05) 0.95 0.94 0.78
Cow efficiency 2.37 2.49 2.35

Weaning weight, cow weight, Body Condition Score (BCS), and mouth soundness score differed (P<05) among the three types, but birth weight and percent calf crop did not. Cow efficiency was calculated from the data presented as weaning weight/cow metabolic weight (body weight to 3/4 power, a measure of energy maintenance requirement). Boran were about 5 percent higher in that measure of efficiency. Based on these results, the Boran appears to offer possibilities for creating efficient crossbred cows. (Texas A&M Univ.; J. Animal Sci: 85, Suppl. 2, p. 7)

A group of 147 heifers, bulls, and steers of mixed British-Continental genetics were used to study the relationship of percentage of eye white and temperament. Temperament was based on subjective chute behavior score and on timed chute escape velocity. Eye white percentage was determined from analyses of video camera images. Eye white averaged 30.1% for heifers, 31.4% for bulls, and 28.6% for steers. Correlations between eye-white percent and chute behavior score were all significant (P<.0001) and were highest for bulls. Correlations with escape velocity were numerically lower but were all significantly higher (at least P<.05), with the highest correlation in heifers. The authors stated that “eye white could be used as a quantitative tool to assess temperament.” (Univ. of Guelph, Ontario, Canada; J. Animal Sci. 87:2168)

High-tannin sorghums have the agronomic advantage of resistance to being eaten by birds. A study was conducted to compare high-tannin sorghum (HTS), corn, or a 1:1 mixture of the two grains for finishing Angus-cross steers. All rations contained about 75% grain. Feeding HTS compared to corn resulted in lower ADG (P<.001), lighter final weight (P<.01), but higher feed efficiency (P<.01). The mixed diet has about the same ADG and final weight as corn and higher feed efficiency (P<.04) than the average of HTS and corn, indicating a positive combination effect.

Compared to corn, HTS steers had less carcass fat cover (P<.01) and superior Yield Grades (P<.04) but, because of lighter carcass weight, had fewer total pounds of boneless, closely trimmed retail product. The mixed diet was intermediate in fat and Yield Grade. Diet did not significantly affect mechanical tenderness. However, HTS-fed samples were found by taste panelists to be less tender (P<.03) and less juicy (P<.01) than those from corn-fed. The mixed ration tended to have slightly higher taste panel tenderness. The authors concluded that a mixture of high-tannin sorghum and corn could be used to produce animal performance and carcass quality attributes similar to a corn-based ration. (Univ. of Wisconsin; J. Animals Sci. 87:2089) 

Mature Angus and Angus X Hereford cows (64 head) were evaluated, with half kept in a drylot (DL) measuring 65 yards by 110 yards and the other half in a 30-acre pasture (PS). Estrous cycles were synchronized using two injections of prostaglandin followed by administration of additional prostaglandin to result in 1, 2 to 3, 4 to 6, or >7 cows being in estrus at the same time.

DL cows had shorter (P<.02) interval to estrus after the last prostaglandin treatment, averaging 61.8 hours compared to 72.8 hours for PS. As more cows were in estrus at the same time, the number of mounts per cow increased (P<.001) and the duration of estrus increased (P<.01). If only one cow was in estrus she received 11.0 mounts in 11.6 hours of estrus. If more than 7 cows were in estrus each cow received 50.4 mounts in 17.3 hours of estrus. DL cows were in estrus longer (P<.04), 16.4 hours versus 14.2 hours for PS. Increasing the number of cows in estrus and concentrating cows in drylot could improve results of AI programs. (Okla. St. Univ.; J. Animal Sci.: 87:1998)

Cattle may adversely affect riparian areas. Providing other sources of water could minimize this affect. A study was conducted over three years on tall fescue/common bermudagrass pasture in the Piedmont area of Georgia. One pasture had water troughs placed 90 to 100 yards from streams. GPS collars were used to study cattle location and movement. When the temperature-humidity index (THI) was from 62 to 72, cows with troughs spent 63 percent less time (52 minutes/day) in riparian zones. But when the THI was from 72 to 84 there was no difference between groups with and without troughs. The authors concluded that sources of water away from riparian zones may improve surface water quality when THI level is not stressful. (Univ. of Georgia and USDA-ARS; J. Animal Sci. 87:2151)

Higher levels of dietary fat have been shown in some studies to have positive effects on beef cow reproduction. Whole raw soybeans have shown the most consistent effects. In this study, 166 dry spring-calving Angus and Angus X Hereford cows wintering on free-choice bermudagrass hay were fed four times/week either 3 lb/feeding of whole soybeans (SB) or 3.5 lb/feeding of soybean meal-hulls (SMH). The supplements were formulated to provide the same daily amounts of protein and energy, but with higher fat from whole soybeans.

During the first 50 days of supplementation, SMH gained more weight (22 lb, P<.001) and more Body Condition Score (0.18 units, P<.004) than SB. However, these effects dissipated by the time calves were weaned. Birth weight of calves from SMH cows tended (P>.06) to be heavier (4.4 lb), but average weaning weights were exactly the same. First-service conception rates and overall pregnancy rates were not significantly different. A subset of 24 cows was used to measure hay consumption and digestibility was that fat was higher in SB, but that did not result in any overall effects on cow or calf performance. (Texas A&M Univ. and Okla. St. Univ.; J. Animal Sci. 86:1868)

Even though the U.S. House has recently voted to stop funding for the National Animal Identification System, external factors might affect this matter. On June 22, South Korea implemented a mandatory tracebook system from consumer to cattle’s place of birth for domestically-produced beef. Some U.S. officials speculate this may eventually be required for imported product. (; 7/10/09)

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