Population analysis of a purebred Hereford and a multibreed synthetic beef cattle herd

International audienc

Effect of restricting silage feeding prepartum on time of calving, dystocia and stillbirth in Holstein-Friesian cows

A study was carried out to investigate the effect of restricting silage feeding on time of calving and calving performance in Holstein-Friesian cows. In the treatment group (n = 1,248 cows, 12 herds) silage feeding commenced in the evening (17:00 to 20:00 h), after a period of restricted access (2 to 10 h) while in the control group ad-libitum access to silage was provided over the 24 h period (n = 1,193 cows, 12 herds). Daytime and nighttime calvings were defined as calvings occurring between the hours of 06:30 and 00:29 and between 00:30 and 06:29, respectively. Restricting access to silage resulted in less calvings at night compared to cows with ad-libitum access to silage (18 vs 22%, P < 0.05). Cows with restricted access to silage had a higher percentage of difficult calvings (11 vs 7%, P < 0.001) and stillbirths (7 vs 5%, P < 0.05) compared to cows in the control group. The percentage of calvings at night was lower (13%) when access to silage was restricted for 10 h compared to 2, 4 or 6 h (22, 18, 25%, respectively) (P < 0.001). Calf sire breed, calf gender or cow parity did not influence time of calving. In conclusion, offering silage to pregnant Holstein-Friesian cows in the evening, after a period of restricted access, reduced the incidence of nighttime calvings, but increased the incidence of dystocia and stillbirth

Efficiency of beef production systems: Description and preliminary evaluation of a model

A deterministic beef efficiency model (BEM) was developed for investigating production efficiency. Efficiency was defined, over the lifetime of the herd, as a ratio of total output (lean meat equivalent) from the herd to total input (feed equivalent in Mcal metabolizable energy, ME) to the herd, and has units of g lean meat Mcal -1 ME. The model combines three tandem submodels describing: (1) growth and feed intake, (2) herd structure, and (3) enterprise efficiency. It is capable of investigating efficiency of production in traditional cow-calf systems, dairy-beef systems as well as systems where an offspring's sex-ratio at birth is controlled. It treats the female and her offspring as the basic herd unit and evaluates efficiency in relation to how long the cow stays in the herd (age at culling) and the degree of maturity of her offspring when marketed, Procedures for validating and evaluating behaviour of a beef efficiency model are described. The model was most sensitive to the degree of maturity of the dam. Increasing the dam's maturity by 10% resulted in a large (up to 35%, depending on breed group) decline in efficiency. The model was moderately sensitive to maturing rate and carcass lean content but was not sensitive to mature size or the inflection parameter. Increasing the maturing rate or lean content by 10% results in up to 8.7% increase in efficiency