Hereford Females Research Articles

Incidence of neurofibroma in cattle in abattoirs in New South Wales.

The incidence of neurofibroma in slaughtered cattle in New South Wales during a four-year period is reported. Most of the cases were in adult Hereford females over 5 years old. In 24 of the herds to which neurofibroma cases were traced there was evidence that the disease had previously occurred in the herd. However, the data does not indicate close familial relationship among cases of neurofibroma.

Effect of Diet Protein Level on Weight Gains of Early Weaned Beef Calves

Forty-eight Angus and Polled Hereford calves were weaned at an average of 48 days of age. Calves were group-fed in dry lot four diets ad libitum which contained 14.5, 18.9, 23.7 and 28.5% crude protein (diets 1, 2, 3 and 4, respectively) with each diet having approximately 14% crude fiber on a dry matter basis. After a 12-day preliminary period, calves were fed for three periods of 6, 6 and 5 weeks. Differences in daily gain due to diet were significant (P<.05) only for Angus. Period effects on daily gain were significant (P<.05) for Angus and P. Hereford males. Angus males gained significantly (P<.01) faster than P. Hereford males and P. Hereford males gained significantly (P<.01) faster than P. Hereford females. Breed-sex × diet interaction did not (P>.05) affect daily gains. Age of calf at weaning was associated with increases in daily gains of .0083 kg (P<05) for Angus and .0099 kg (P<.01) for P. Hereford males per day increase in age. Results of apparent digestibility indicated an increase (P<.05) in the digestibility of crude protein for each increase in crude protein content of the diets. Nitrogen retention of diet 1 was significantly (P<.05) lower than the other diets with the other three diets not differing significantly although the trend showed an increase in nitrogen retention with increases in protein content of the diets. Comparison of daily gain response from the various diets was made with those expected from N.R.C. protein requirements.

Phenotypic Relationships within Angus and Hereford Females. II. Repeatabilities of Progeny Weaning Weights

Phenotypic Relationships within Angus and Hereford Females. II. Repeatabilities of Progeny Weaning Weights

Phenotypic Relationships within Angus and Hereford Females. I. Heifer Growth and Subsequent Cow Productivity

Phenotypic Relationships within Angus and Hereford Females. I. Heifer Growth and Subsequent Cow Productivity

Relationship between Preweaning Nutritional Management and the Growth and Development of Angus and Hereford Females

A Total of 206 Angus and Hereford females were used in four trials to determine the effects of three preweaning planes of nutrition imposed by (1) weaning at 140 days, (2) weaning at 240 days and (3) creep-feeding and weaning at 240 days. At 240 days of age, 140-day weaned, 240-day weaned and creep-fed females weighed 175.7, 206.5 and 226.0 kg, respectively. After weaning, all females were treated alike under range conditions. Weights and body measurements, actual and photographic, were taken at 140 days, 240 days, 1.0 year and 6-month intervals thereafter to 4.5 years. Body weight, length of body, height at hooks and withers, and circumference of heart girth were significantly (P<.05) affected by treatment to 1.5 years. The creep-fed females gained the least and the 140-day weaned females the most in structural size between 240 days and 2.0 years of age. The creep-fed females lost more weight and condition during their first pregnancy (which coincided with their first winter) than did the other treatments (which remained rather constant). The creep-fed group also showed a greater decrease in rate of skeletal growth than the other treatments during this period. No significant difference (P>.10) for any measurement of height between 240-day weaned and creep-fed groups was ever noted, although a significant (P<.05) difference between extreme treatments was apparent through 1.5 years of age. The 140-day weaned group tended to remain smaller for all variables studied, but differences after 1.5 years of age were small.

Relationship between Preweaning Nutritional Management and Subsequent Performance of Angus and Hereford Females through Three Calf Crops

A Total of 206 Angus and Hereford females in four trials conducted under range conditions were studied under three nutritional management systems imposed by weaning at 140 days, weaning at 240 days, and creep-feeding followed by weaning at 240 days. At completion of treatments at 240 days of age, weights (kg) of the respective treatment groups were 182.1, 221.0 and 234.0 for Angus and 169.2, 202.0 and 217.9 for Herefords. The females, bred to calve first at 2 years of age, were allowed to produce calves through 4 years of age. Birth weight of first calves was heaviest (P<.05) from creep-fed females. Although differences were not statistically significant (P>.05), creep-fed females weaned the lightest calves in each of the three calf crops; their calves had the lowest condition scores (P<.10 and .005) in calf crops 1 and 3. Milk yield also tended to be lowest for creep-fed females, and highest for 240-day weaned females. None of eight additional estimates of size of the progeny at 140 days of age was consistently influenced by preweaning nutritional management of the dam.

Estimates of Genetic, Environmental and Phenotypic Parameters in Range Hereford Females

Data collected on Hereford females at the United States Range Livestock Experiment Station, Miles City, Montana, from 1934 through 1959 were used to obtain heritability estimates and genetic, environmental, and phenotypic correlations among weights, gains, and scores from birth through mature weight. These estimates were used to predict expected change from direct and correlated responses from single trait selection. Heritability estimates obtained from paternal half-sib analyses were birth weight, 0.38; gain from birth to weaning, 0.40; 180-day weaning weight, 0.43; weaning score, 0.28; gain from weaning to 12 months, 0.45; 12-month weight, 0.41; gain from 12 to 18 months, 0.35; 18-month weight, 0.50; 18-month score, 0.13; mature spring weight, 0.52; and mature fall weight, 0.57. Genetic correlations among all weights and gains were fairly high, 0.40 to 0.99, except for those involving gain during the first winter from weaning to 12 months. Selection for 18-month weight appears to be a good single criterion for selection for growth throughout life.