Estimation of Genetic and Maternal Effects in Crossbred Cattle of Angus, Charolais and Hereford Parentage. I. Birth and Weaning Weights

Weaning performance of calves sired by Charolais and Hereford on dams of Angus, Bonsmara and Hereford and various crossbred dam combinations was compared. Charolais sired calves were on average 5 kg heavier at birth and 20 kg heavier at weaning than Hereford sired calves. Among the three straightbred dam breeds, the Bonsmara weaned calves that were approximately 6% heavier than both the Angus and the Hereford calves. The use of crossbred dams having intermediate levels of Charolais composition is suggested in crossbreeding programmes in intensive production systems based on cultivated pastures under irrigation.

Section: Resultssupporting

confidence: 64%

The effect of Charolais and Hereford sires and straightbred and crossbred dams on pre-weaning growth of calves

Dadi¹,

Jordaan²,

Schoeman³

et al. 2002

“…The high positive Afrikaner maternal direct effect contradicts reports that seem to indicate that Sanga and Zebu type dams restrict the BW of their calves (Roberson et al, 1986;Comerford et al, 1987;Tawonezvi et al, 1988;Scholtz et al, 1990;Van Zyl et al, 1992;Franke, 1994), even when mated to late maturing Bos taurus sires with a positive additive effect on BW (Alenda et al, 1980) by way of a large negative maternal effect (Roberson et al, 1986).…”

Section: Resultscontrasting

confidence: 48%

“…The direct maternal effect for the Hereford was positive in some investigations (Alenda et al, 1980;Dillard et al, 1980;Cunningham & Magee, 1988;Schoeman et al, 1993;Arthur et al, 1994;Franke, 1994), while it was negative in others (Gregory et al, 1978), depending on the breeds it was compared with. Schoeman et al (1993) also obtained a negative direct maternal effect for the Simmentaler while Cunningham & Magee (1988) obtained positive direct maternal effects for the Simmentaler.…”

Section: Resultsmentioning

confidence: 99%

“…The direct maternal effect for the Hereford was positive in some investigations (Dillard et al, 1980;Koch et al, 1985;Cunningham & Magee, 1988;Arthur et al, 1994), while it was negative in others (Gregory et al, 1978;Alenda et al, 1980;Schoeman et al, 1993;Franke, 1994), depending on the breeds it was compared with. It is also known that the Hereford is a low milk producing breed (Jenkins & Ferrell, 1992).…”

Section: Resultsmentioning

confidence: 99%

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Estimates of crossbreeding parameters in a multibreed beef cattle crossbreeding project

Skrypzeck¹,

Schoeman²,

Jordaan³

et al. 2000

Data from purebred and crossbred cattle, consisting of the Afrikaner (A), Simmentaler (S) and Hereford (H) breeds managed in a relatively intensive but high stocking rate environment, were analysed to estimate breed direct effects, individual heterotic effects, breed maternal and maternal heterotic effects for birth weight (BW) and weaning weight (WW). Simmentaler breed direct effects, expressed as deviation from the general mean, were positive (P ≤ 0.01) for both traits. Hereford and Afrikaner breed direct effects were negative (P ≤ 0.01) for both traits while the Afrikaner breed direct effects exceeded those of the Hereford. Afrikaner direct maternal effects were positive (P ≤ 0.01) for both traits. The Hereford direct maternal effect was negative (P ≤ 0.05) (-2.9%) for WW. Simmentaler maternal effect was negative (P ≤ 0.01 ) for BW but non-significant (P ≥ 0.05) for WW. Individual heterotic effects for BW were significant (P ≤ 0.01) in H x S (3.5%) and S x A (11.0%) only. Individual heterotic effects were positive (P ≤ 0.01) for WW, with that of the H x A (9.8%) and S x A (6.7%) crosses exceeding the S x H (3.1%) cross. Maternal heterotic effects were non-significant (P ≥ 0.05) for both BW and WW .

“…These techniques were based mainly on linear functions of the various cross means or multiple regression procedures (Alenda et al, 1980;Dillard et al, 1980;Robison et al, 1981;Cunningham & Magee, 1988;Schoeman et al, 1993;Skrypzeck et al, 2000). Generally, the importance of additive, maternal and non-additive genetic effects was determined and used for prediction of the performance of crosses that have not actually been tested.…”

Section: Introductionmentioning

confidence: 99%

The influence of outliers on a model for the estimation of crossbreeding parameters for weaning weight in a beef cattle herd

Aziz¹,

Schoeman²,

Jordaan³

2002

Data on 17348 weaning weight records from a beef cattle crossbreeding operation were used to determine the effect of outliers on regression coefficients. Different criteria were used for detecting potential influential points. Eliminating a small number (932 or 5.4%) influential points resulted in the improvement of the model fitted. The R 2 values increased from 41% to 49% while the mean square error was reduced from 672.9 to 500.4. The use of diagnostic statistics for detecting influential observations is recommended before any analysis is performed.