A descriptive background is given to a group of beef farms in Jamaica on which a series of grass and animal production studies were carried out using technical and economical data derived from those farms over a 5-year period. During this time the farms co-operated in keeping standardized costaccounts and recording detailed outputs from farms and from improved and unimproved lands within those farms. Studies were made of the economics of pasture improvement and also of improvement in husbandry and breeding programmes. The possible value of the results to the small farms in the area is discussed.

1. The data used in this study were the estimated 210-day weights of 2351 calves born on eight farms in the years 1958–61. In each year data were only used from herds which recorded at least five calves of each sex in that year. One hundred such herd years were included in the study.2. The mean 210-day difference in weight between male and female calves was 27 lb. 1202 male calves had a mean weight of 380 lb. and 1149 female calves had a mean weight of 353 lb.3. The response of calf weight to age of dam was different in the two sexes. The weight of the female calf was found to increase with dam age in a linear fashion, whereas the response of male calves was best described by a quadratic relationship with the maximum response at a dam age of 8 years.

Yields from improved (pangola) and unimproved pastures on a group of beef cattle farms have been recorded during the years 1958–62. On these farms it was shown that there was a highly significant relationship between the percentage of improved grassland and the live-weight output per acre of the whole farm. This relationship indicated that the output of unimproved land on these farms was of the order of 45 lb. per acre, and that of improved (pangola) pasture 260 lb. per acre.

No abstract

1. The age of 210 days was selected for calf weight standardization. In general this is a preweaning weight under prevailing Jamaican conditions, and it represents a compromise between a very early age (90–120 days) which would reflect closely the milking ability of the dam, and the actual weaning age (approximately 260 days) when the grazing management of the herd would constitute a major unpredictable variable.2. Either one or two weighings taken between the fourth and the ninth months of life was used to standardize calf weights to 210 days of age. In either instance for groups of calves, a mean estimate was derived which was very close to the actual mean 210-day weight, and which was suitable for data relating to groups of animals.