Arkansas - Agricultural Communication Services - University of ...

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Arkansas Animal Science Department Report 2001 Table 1. Descriptive statistics for ultrasound data. Trait a Number of records Mean Standard deviation LMAU, in 2 1298 11.13 2.25 FTU, in 1298 0.22 0.10 PFAT, % 1215 3.27 0.92 YW, lb 1170 1030.51 188.23 a LMAU = 12 th -rib longissimus muscle area, ultrasonically measured on live yearling bulls and heifers; FTU = 12 th to 13 th -rib back fat thickness, ultrasonically measured on live yearling bulls and heifers; PFAT = Percent intramuscular fat from 12 th -rib longissimus muscle area, ultrasonically measured on live yearling bulls and heifers; YW = Live weight of yearling bulls and heifers taken at time of ultrasound. Table 2. Genetic and phenotypic (co)variance a estimates for yearling live-animal ultrasonic measurements for carcass traits. Measurement b LMAU FTU PFAT YW LMAU 19.664 -0.041 -0.327 57.710 (43.862) FTU 0.276 0.010 0.011 1.226 (0.027) PFAT -0.184 -0.014 0.091 2.592 (0.494) YW 82.170 1.322 -1.715 841.982 (753.894) a On diagonal, additive genetic variance with residual variance below diagonal in parentheses. Above diagonal direct additive (co)variance, below diagonal residual (co)variances. b LMAU = 12 th -rib longissimus muscle area, ultrasonically measured on live yearling bulls and heifers; FTU = 12 th to 13 th -rib back fat thickness, ultrasonically measured on live yearling bulls and heifers; PFAT = Percent intramuscular fat from 12 th -rib longissimus muscle area, ultrasonically measured on live yearling bulls and heifers; YW = Live weight of yearling bulls and heifers taken at time of ultrasound. Table 3. Two-trait Heritabilities and Correlations a for Estimates of Ultrasonic Carcass Characteristics. Measurement b LMAU FTU PFAT YW LMAU 0.31 -0.09 -0.25 0.44 FTU 0.16 0.27 0.36 0.42 PFAT -0.08 0.17 0.15 0.31 YW 0.44 0.33 0.03 0.53 a Heritability estimates on diagonal, genetic correlations above diagonal, phenotypic correlations below diagonal. b LMAU = 12th-rib longissimus muscle area, ultrasonically measured on live yearling bulls and heifers; FTU = 12th to 13th-rib back fat thickness, ultrasonically measured on live yearling bulls and heifers; PFAT = Percent intramuscular fat from 12th-rib longissimus muscle area, ultrasonically measured on live yearling bulls and heifers; YW = Live weight of yearling bulls and heifers taken at time of ultrasound. 52
Breed-Type x Forage Interaction for Mature Weight and Rate of Maturing for Angus, Brahman, and Reciprocal Cross Cows B. A. Sandelin, 1 A. H. Brown, Jr., 1 M. A. Brown, 2 Z. B. Johnson, 1 and A. M. Stelzleni 1 Story in Brief Mature weight (A) and rate of maturing (k) were estimated in 177 Angus, Brahman, and reciprocal cross cows grazing Bermudagrass (BG) or endophyte-infected tall fescue (E+) to evaluate breed-type x forage interactions. Data were collected every 28 d until approximately 18 mo of age and then at prebreeding, postcalving, and weaning of calf. Mature weight and k were estimated using Brody’s model. Data were pooled over year and analyzed by the general linear model (GLM) procedure of SAS. Models for A and k included the independent variables of breed-type, forage and breed-type x forage interaction. There was a significant (P < 0.01) breed-type x forage interaction for A, but not for k. Angus cows had greater (P < 0.01) mean A on E+ than did Angus x Brahman cows on BG. Angus x Brahman cows grazing BG had lower (P < 0.05) mean A than did Brahman x Angus cows grazing BG or E+ and Brahman cows grazing BG. Angus cows had a slower (P < 0.05) mean k than Angus x Brahman and Brahman x Angus cows, and Angus x Brahman cows had a faster (P < 0.05) mean k than Brahman x Angus and Brahman cows. These data suggest that the choice of breed-type is important for maintaining a crossbreeding program, in that mature size and rate of maturing are critical to the match of animal requirements to available production resources. Introduction The growth parameters of mature weight (A) and rate of maturing (k) have been shown to be of biological importance to the efficiency of beef production. These parameters are major determinants of the amount of energy needed to grow and mature properly. The availability of adequate production resources often hinders the level of efficiency needed to sustain this level of energy. These parameters may be useful to producers who are trying to find the ideal animal to match available resources. There have been numerous papers that deal with the calculation of A and k in many breeds of cattle, however, a review of literature found a limited amount of growth curve data for crossbred cattle. Problems associated with endophyte-infected tall fescue (E+) have been extensively documented. The objective of this study was to look at the interaction of breed-type x forage for the growth parameters of A and k in Angus, Brahman, and reciprocal cross cows grazing common bermudagrass or endophyte-infected tall fescue. Experimental Procedures Base Herd Development. Eighty purebred Angus and 80 purebred Brahman heifers born in the spring of 1985 were purchased from approximately 20 different sources per breed in the fall of 1985 and winter of 1986. Of these heifers, 32 and 30 different sires were represented in Angus and Brahman breeds, respectively. Heifers were stratified according to source and assigned at random to one of four 36-acre BG pastures and one of four 36-acre ‘Kentucky-31’ E+ pastures. Stocking rate for each pasture within forage environment ranged from 19 to 24 head, with approximately equal numbers of Angus and Brahman. Heifers were managed as commercial replacement heifers to gain approximately 0.80 lb/d by supplementing with cottonseed meal, corn, and E+ or BG hay according to visual estimates of forage DM availability and normal quality curves for either BG or E+. Normally, supplemental feed was provided from late November to late April for both forage treatment types; supplemental grain (2.0 lb per animal per day) was continued in the E+ treatment into late fall and early spring in an attempt to moderate potential toxicity from the forage. Minerals were fed free choice throughout the year. Heifers were bred as 2-yr-olds to calve at 3 yr of age to preclude introducing parity differences into the study due to the low percentage of purebred Brahman reaching sexual maturity at 15 mo of age. They were bred during 75 d breeding seasons. Five sires of each breed were used in this study. Sires were rotated among breeding pastures in both forage treatments to prevent confounding of sire and forage effects, and breed of sire was alternated in a breeding pasture to facilitate sire of calf identification. Study Animals. Calves were born from late February to late May each year. Weights were taken, and calves were tagged at birth. The post-weaning backgrounding environments were designed to imitate two commercial situations: 1) a warm season, dormant forage environment (BG) and 2) a cool-season forage environment (E+) where growing forage is available for a portion of the evaluation period and supple- 1 Department of Animal Science, Fayetteville 2 USDA-ARS, Grazinglands Research Laboratory, El Reno, OK 53
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Arkansas Animal Science Department
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spine copy ARKANSAS ANIMAL SCIENCE
Page 6 and 7: INTRODUCTION The faculty and staff
Page 8 and 9: COMMON ABBREVIATIONS Abbreviation T
Page 10 and 11: The Effects of Nitrogen Fertilizati
Page 12 and 13: Arkansas Animal Science Department
Page 14 and 15: Demographics and Academic Success o
Page 22 and 23: Efficacy of Mannan Oligosaccharide
Page 26 and 27: Effects of Dietary Magnesium and Ha
Page 36 and 37: Effect of Feather Meal on Live Anim
Page 42 and 43: Maternal Effects for Performance Te
Page 60 and 61: Supplementation of Beef Cows and He
Page 70 and 71: Influence of Supplementing Cobalt i
Page 80 and 81: Long-Term Immune Response of Beef H
Page 92 and 93: Small Grain Forage for Stocker Catt
Page 100 and 101: Economics of Production Systems Inv
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Influence of Moisture Concentration
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Impact of Spontaneous Heating Durin
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Effects of Tall Fescue Inoculated w
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Yield and Nutritive Value of Easter
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2000 Dairy Herd Improvement Herds i
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The Impact of Multiple Antimicrobia
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The Impact of Multiple Antimicrobia
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The Use of Hurdle Technology to Red
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Consumer Acceptability of Forage Fe
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