AGE DYNAMICS OF CHANGES IN LINEAR GROWTH PARAMETERS OF REPLACEMENT HEIFERS UNDER DIFFERENT APPROACHES TO THE ORGANIZATION OF THEIR FEEDING TECHNOLOGY
Authors: Drozdova Oksana 
Published: August 2024

The dynamics of changes in body weight and parameters of linear growth of replacement heifers of the Ukrainian black-and-white dairy breed under different approaches to the organization of their feeding technology were studied. The research was conducted on replacement heifers of the Ukrainian black-and-white dairy breed with a body weight of 170 kg, since they were 6 months old. For the formation of the experimental groups, different approaches to the organization of their feeding technology were used, namely, heifers of the control group received a diet that included corn silage. In feeding the animals of the second and third (experimental) groups, respectively, 50% and 100% of such silage was replaced by mixture of corn and sorghum.

After analyzing the silage used in the experiment, no significant differences in their chemical composition were found. Therefore, the use of silage prepared from the green mass of compatible crops of corn and sorghum as part of the diets of replacement heifers did not have a significant effect on changes in their nutritional value and the content of nutrients in them, as well as the content of crude protein, provided that detailed feeding standards are met. In particular, the increase in the content of crude fiber, based on 1 kg of dry matter of the diets, was 3 and 6 g, respectively, in the animals of the second and third groups.

In the course of the experiment, no significant and probable difference was established in terms of the increase in body weight of replacement heifers from the control and experimental groups. However, at the end of the experiment, a statistically significant difference in growth intensity was established between the animals of Group III (experimental) and Group I (control), while the differences between the latter and Group II (experimental) increased to the trend level. In particular, an increase in average daily gains of heifers of experimental groups, compared to animals of the control group, on the fourth and fifth months of the experiment, respectively, by 4.0 and 6.4% and by 5.2 and 11.2% (р≤ 0.05). It was also established that the use of both traditional corn and corn and sorghum silage in the organization of animal feeding technology accelerates the achievement of economic maturity by heifers. It was determined that the body weight of replacement heifers, from the age of eight months, exceeded the requirements of the breed standard. In particular, the body weight of 8-month-old heifers was higher than the standard by 5.0 – 10.2 kg or 2.4 – 4.9%, at the age of 9 months it was higher by 11.0 – 15.7 kg or 4.8 – 6 .9%, at the age of 11 months it was higher by 30.2 – 33.0 kg or 11.4 – 12.4%.

The variability and level of body structure indices in the age dynamics of experimental animals of the Ukrainian black-and-white dairy breed proved the positive dynamics of the formation of the exterior in the direction of the dairy type. Thus, the obtained results proved the expediency of using corn and sorghum silage in the technology of rearing replacement heifers.