Genetic and environmental influences on beef cattle production in Zambia 3. Carcass characteristics of purebred and reciprocally crossbred castrated males

Thorpe, W.R.; Cruickshank, D. K. R.; Thompson, R.

doi:10.1017/s0003356100024028

Cited by 8 publications

(2 citation statements)

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“…Thorpe, Cruickshank and Thompson (1979) have shown that Bos taurus-sired F, progeny had relatively greater live and carcass weight advantages over purebred Angoni, Barotse and Boran progeny than did the crossbred progeny of these breeds (Thorpe et al, 1980b;Thorpe, Cruickshank and Thompson, 1980c). Hence, to utilize heterosis fully, Bos taurus crossbreeding should be considered in Zambia.…”

Section: Discussionmentioning

confidence: 99%

Genetic and environmental influences on beef cattle production in Zambia 4. Weaner production from purebred and reciprocally crossbred dams

Thorpe¹,

Cruickshank²,

Thompson

1981

Anim. Sci.

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Estimates of dam reproductive performance are reported for purebred Africander, Angoni, Barotse and Boran dams, and the reciprocal crossbreds of the latter three breeds, under ranching conditions in Zambia.Mean performances based on a maximum of 1996 records collected over six parities were: calving rate, 65-6%; weaning rate, 62-8%; calf birth weight, 26-6kg; calf weaning weight, 163-6kg; and dam live weight at weaning, 363 0 kg.Purebred Africander and Barotse dams had significantly poorer calving rates, 542 and 57-6% respectively, than the purebred dams of the Angoni and Boran breeds, 69 1 and 66 0% respectively. Reciprocal crossbred dams of the latter two breeds had the highest calving rates, 71-2 and 744%. Heterosis estimates for calving rate were 0-8% for Angoni/Barotse crosses, 7-8% for Angoni/Boran crosses and 10-3% for Barotse/Boran crosses and, for weaning rate, 3-7, 6-7 and 11 5% respectively. There were no differences between reciprocal crossbred dams for calving and weaning percentages. The mortality rate of calves born to crossbred dams was 4 0 % and that of the calves born to purebred dams of the same breeds 4-7 %. Dam status at mating had an important effect on fertility with the calving rate of dams dry at mating, 89-1 %, contrasting with a rate of 39-8% for those dams that were lactating at mating and that had calved late in the season.There were large differences between breeds for calf weights but heterosis estimates were small and nonsignificant. There were no differences between the progeny weights of reciprocal crossbred dams. Sex, date and period of birth, and dam status had significant effects on calf weights.Africander dams had the heaviest, and Angoni dams the lightest, live weights at weaning, 421 1 and 320-7 kg respectively. Heterosis estimates for dam live weights were small and non-significant, and reciprocal crossbred differences were unimportant. Dams which lost most live weight during the dry season, that had extremely light live weights at the beginning of the breeding season or that gained little weight during the breeding season had significantly poorer fertility than other dams.Overall estimates of heritability derived by dam/daughter regression were 0-20 for calving percentage, 0-76 for calf birth weight and 0-72 for calf weaning weight.

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Section: Discussionmentioning

confidence: 99%

Genetic and environmental influences on beef cattle production in Zambia 4. Weaner production from purebred and reciprocally crossbred dams

Thorpe¹,

Cruickshank²,

Thompson

1981

Anim. Sci.

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“…No studies have estimated these effects for meat quality attributes in cattle reared in the tropics. Thorpe et al (1980) compared Africander, Angoni, Barotse and Boran breeds and reciprocal crosses of the latter 3 breeds in Zambia. For all carcass characters except those related to size, the Sanga breeds (Africander and Barotse) were very similar, as were the 2 zebu breeds (Angoni and Boran).…”

Section: Estimates Of Heterosismentioning

confidence: 99%

Quantitative and molecular genetic influences on properties of beef: a review

Burrow¹,

Moore²,

Johnston³

et al. 2001

Aust. J. Exp. Agric.

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Abstract. The scientific literature is reviewed to identify quantitative and molecular genetic influences on quantity and quality of beef. Genetic variation between breeds is of similar magnitude to genetic variation within breeds for many economically important traits. Differences between breeds are significant and large for most carcass and beef quality attributes, including beef tenderness, although differences for sensory juiciness and flavour are of little practical importance. For traits such as beef tenderness, between-breed differences may be more easily exploited than within-breed differences, because exceptional breeds are easier to identify than exceptional animals. Effects of heterosis on carcass and beef quality attributes are relatively small (3% or less), with most effects mediated through heterotic effects on weight. Carcass composition traits (e.g. carcass weight, fat thickness and marbling) are moderately to highly heritable. Most estimates of retail beef yield percentage are highly heritable, offering good potential for within-breed selection for the trait, although a moderate to strong antagonistic relationship exists between yield and marbling. This relationship needs to be considered in within-breed selection programs for yield percentage. Early estimates of heritability of objective measures of beef tenderness (Warner Bratzler shear force values) indicated tenderness was moderately to highly heritable. Recent estimates using larger numbers of carcasses and more discriminatory methods of analysis indicate that beef tenderness is lowly heritable in Bos taurus breeds and moderately heritable in Bos indicus and Bos indicus-derived breeds. Within breeds, measures of 24-h calpastatin activity are genetically strongly correlated with shear force values but are more heritable. However, phenotypic correlations between shear force values and 24-h calpastatin activities are low. There are also inconsistencies in relationships between these measurements across breeds. Low correlations between tenderness in different muscles, low to moderate heritabilities and inconsistent variation within-and between-breeds for traits such as 24-h calpastatin activity suggest that genetic improvement in beef tenderness may be difficult. The possibility exists that significant mitochondrial genetic effects occur for some carcass and beef quality attributes. A major gene for muscular hypertrophy in cattle significantly affects carcass and beef quality characteristics. Genome-wide screening of DNA markers indicates a number of putative Quantitative Trait Loci (QTL) associated with carcass and meat quality characteristics. Published data for these QTL are summarised. Strategies to combine quantitative and molecular genetic information to maximise genetic progress are discussed.

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The basicranium of Plio‐Pleistocene hominids as an indicator of their upper respiratory systems

Laitman

Heimbuch

1982

American J Phys Anthropol

136

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Our analyses of extant primates have shown that a relationship exists between the degree of flexion of the basicranium and the location of upper respiratory structures such as the larynx and pharynx (Laitman et al., 1978). Based upon these relationships, we have previously used the basicrania of late Pleistocene hominids as a guide to the reconstruction of their upper respiratory anatomy (Laitman et al., 1979). This study continues our approach by examining the basicrania of Plio-Pleistocene hominids and reconstructing their upper respiratory systems. Nine Plio-Pleistocene hominids had basicrania complete enough to be used in this study. These included the originals of Sts 5, MLD 37/38, SK 47, SK 48, SK 83, Taung, KNM-ER 406, OH 24, and a cast of OH 5. Craniometric analysis of the basicrania of these specimens showed that they had marked similarities to those of extant pongids. These basicranial similarities between Plio-Pleistocene hominids and extant apes suggest that the upper respiratory systems of these groups were also alike in appearance. As with living nonhuman primates, the early hominids probably exhibited a larynx and pharynx positioned high in the neck. This high position would have permitted an intranarial epiglottis to be present during both normal respiration and the ingestion of a liquid bolus of food. The high position of the larynx would have also greatly restricted the supralaryngeal portion of the pharynx available to modify laryngeal sounds. It is thus possible that the Plio-Pleistocene hominids exhibited modes of breathing, swallowing and vocalizing similar to those of living apes.

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Genetic and environmental influences on beef cattle production in Zambia 3. Carcass characteristics of purebred and reciprocally crossbred castrated males

Cited by 8 publications

References 8 publications

Genetic and environmental influences on beef cattle production in Zambia 4. Weaner production from purebred and reciprocally crossbred dams

Genetic and environmental influences on beef cattle production in Zambia 4. Weaner production from purebred and reciprocally crossbred dams

Quantitative and molecular genetic influences on properties of beef: a review

The basicranium of Plio‐Pleistocene hominids as an indicator of their upper respiratory systems

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