БИОЛОГИЧНО ОТГЛЕЖДАНЕ НА МЪЖКИ ТЕЛЕТА, ХЕРЕФОРДСКИ КРЪСТОСКИ С ГОВЕДА ОТ МЛЕЧНИ ПОРОДИ

Абстракт

One way dispersion analysis was used in a study on the influence of organic rearing of male calves, crosses of dairy breeds with Hereford sires. The scientific-production experiment included 2 groups of 12 calves each which were born in biological farms. The dairy breeds were Bulgarian Black-and-White and Bulgarian Brown cattle. At the beginning of the experiment the animals were divided by the analogous method according to their breed, live weight and age. The control group contained an equal number of calves of the two dairy breeds, and the experimental one contained Hereford crosses corresponding in number with the dairy breeds. This principle of analogous representation was maintained during the entire experiment. The animals were fed at lib with whole ration mixture which contained grass hey and 1 kg concentrate forage daily with 13% protein content produced from biologically permitted components. The experiment lasted until an average live weight of 430 kg was reached. It was obtained that the Hereford sire breed used in the commercial crossing schemes with dairy dam breeds under biological conditions was a considerable factor for growth intensity to 12 months of age ( <0.01), slaughter yield ( <0.001) and first grade meat ( <0.01). A highly significant increase ( <0.001) of the slaughter yield with 2.49% and an increase of the conformation score with one class for the Hereford breeds was observed. The Hereford breed influenced favorably the amount of the first grade meat and the linear contrast of 10.89 kg was considerable and significant ( <0.01).