Evaluating the Influence of Sex on Birth Weight and Preweaning Gain in Beef Cattle

Koch, R. M.; Gregory, K. E.; Ingalls, J. E.; Arthaud, R. L.

doi:10.2527/jas1959.182738x

Cited by 22 publications

(11 citation statements)

References 7 publications

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“…Koch et al (1959) recommended additive adjustments where standard deviations were equal, and multiplicative adjustments where coefficients of variation were equal. The effects of additive and multiplicative adjustment factors (based on least-squares estimates of age-of-dam effects) on the variances of Hereford and Angm weight data adjusted to 550 days of age by Methods T, II.…”

Section: A~e Of Dammentioning

confidence: 99%

Adjustment factors for Hereford and Angus cattle weights

Nicoll

Rae

1978

New Zealand Journal of Agricultural Research

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The l8-month weights of 4703 Hereford (16 herds) and 10226 Angus (33 herds) cattle, recorded over 8 years in the Beef Cattle Weight Gain Performance Recording Scheme, were analysed to estimate age and age-of-dam effects, and to evaluate present and alternative weight adjustment procedures. For least-squares analyses, l8-month weights were classified within breed and sex into herd, year-of-birth_ and age-of-dam group effects, with age at weighing as a covariate. Separate analyses evaluated the importance of each first-order interaction among herd, year, and age-of-dam group effects. All main effects and the herd x year interaction were highly significant sources of variation (P < 0.001) and were considered to be of practical importance. The mean l8-month weight of Hereford males (females) was 496.9 ± 0.7 kg (356.7 ± 1.3 kg), and of Angus males (females) was 455.4 ± 1.0 kg (318.5 ± 1.4 kg). Corresponding linear regression coefficients of weight on age were 0.55 ± 0.02 kg/day (0.45 ± 0.02 kg/day) for Hereford, and 0.64 ± 0.02 kg/day (0.36 ± 0.01 kg/day) for Angus. Adjustment for age by either additive or multiplicative linear regression coefficients of weight on age eliminated the dependence of weight on age in the data analysed, whereas adjustment by the procedure used in the National Beef Recording Service (NBRS) did not. Age-of-dam effects estimated by least-squares did not generally differ from those estimated by best linear unbiased estimation, with the exception of the weight of cattle reared by 2-year-old Hereford dams. After adjustment of weights on a sample of the data by both NBRS procedures (employing age-of-dam adjustments on 200-day weight), and by factors estimated by least-squares analysis, the rankings of individuals within breed, herd, und se>;: tended to differ between the adjustment procedures. On the basis of equalising variances within age-of-dam subclasses, it was concluded that additive adjustments for age-of-dam effects were appropriate, particularly those derived by best linear unbiased estimation.

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Section: A~e Of Dammentioning

confidence: 99%

Adjustment factors for Hereford and Angus cattle weights

Nicoll

Rae

1978

New Zealand Journal of Agricultural Research

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“…Here, the weighted mean for the bull-heifer difference was 11 kg based on 5374 observations from five studies (Koch, Gregory, Ingalls and Arthaud, 1959;Brinks et ah, 1961;Vernon et ah, 1964;Jeffrey, Berg and Hardin, 1971;Kennedy and Chirchir, 1971), and 10 kg for the steer-heifer difference which was based on 5498 observations from two studies (Brinks et al, 1961;Sewell, Comfort, Day and Lasley, 1963). Here, the weighted mean for the bull-heifer difference was 11 kg based on 5374 observations from five studies (Koch, Gregory, Ingalls and Arthaud, 1959;Brinks et ah, 1961;Vernon et ah, 1964;Jeffrey, Berg and Hardin, 1971;Kennedy and Chirchir, 1971), and 10 kg for the steer-heifer difference which was based on 5498 observations from two studies (Brinks et al, 1961;Sewell, Comfort, Day and Lasley, 1963).…”

Section: Resultsmentioning

confidence: 99%

The effects of selection on sex differences in pre-weaning growth in beef cattle

Hopkins

1977

Anim. Sci.

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Pre-weaning growth data from 3822 calves reared in 11 Victorian herds were analysed. The results suggested that the superiority of males (bulls) over castrated males (steers) in pre-weaning growth was due, at least partly, to the early castration of poorly growing male calves, i.e. to the effects of early selection. The extent of this selection bias was further examined using results from similar studies and from experiments in which bulls and steers were selected without bias. These studies strongly supported the view that the superiority of bulls over steers was primarily due to selection and not to sex effects. If sex did influence the bull-steer difference it was of no statistical or practical importance. In the Victorian data, the ratio of bulls to steers was higher in subclasses in which average growth rates were higher. When selection effects are correlated in this way with other environmental effects such as age of dam effects further biases may arise in estimation of those effects and hence in individual or mass selection. The results indicated, therefore, that unless bulls and steers are treated as one sex biases can arise in both individual selection and progeny selection.

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“…After the first year, however, correction factors were calculated from our records according to methods described by Koch, Gregory, Ingalls and Arthaud (1959) so that adjustments could be made to live-weight data to account for sex differences between calves. As far as possible herd constitution remained the same from year to year of the trial.…”

Section: Methodsmentioning

confidence: 99%

Intensification of the spring-calving single-suckler herd

Powell¹

1972

Anim. Sci.

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1. For four consecutive years, each one of four herds of 13 cows and calves grazed land stocked and fertilized at one of the following combinations of rates (ha/cow, kg N/ha): 0-61, 82; 0-51, 82; 0-51,203 and 0-40, 203. 2. The Devon and Devon x British Friesian cows present in each herd reared calves by Devon bulls. Calving occurred indoors over the period February to April, the cows having been housed in early December. 3. Live-weight gains of calves to weaning in mid-October did not differ between herds in any year. Live-weight increase of cows over the grazing season was similar and substantial in all herds. On average pure-bred calves were 25 kg lighter at weaning than the cross-bred calves. 4. The main difference between treatments was in quantity of grass conserved and it was only in the herd kept at 0-51 ha/cow, 203 kg N/ha that enough was made to supply all the energy needs of the herd for a 150-day winter. 5. Gross margins/ha were greatest at the higher rate of nitrogen application but no further improvement was evident at the maximum stocking rate. The importance of maximizing output/animal is discussed.

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Evaluating the Influence of Sex on Birth Weight and Preweaning Gain in Beef Cattle

Cited by 22 publications

References 7 publications

Adjustment factors for Hereford and Angus cattle weights

Adjustment factors for Hereford and Angus cattle weights

The effects of selection on sex differences in pre-weaning growth in beef cattle

Intensification of the spring-calving single-suckler herd

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