The growing demand for meat pork requires significant changes in the gene pool of animals, improvement of existing breeds and imports from countries with developed pig specialized beef genotypes. Use in hybridization imported breeds provides a large gain, reduces feed costs and increases profitability. Study of the ontogeny of animals of different breeds and their hybrids allows to determine the optimal parameters of technology and feeding that will maximize the genetic potential of specific genotypes. A significant contribution to the theory of ontogenesis made famous scientists Sven K. B., B. N. Kovalenko, Medvedev Century A. and others. They found that different breeds have different physiological maturity and pass the stages of development at different rates. Given the changes in technology and feeding in which it occurs and the selection process and the production of pork, there is a need for further study of the influence of all these factors, and genetic and Parfyonova character on the ontogeny of animals. Therefore, we carried out a study of the growth and development of pigs specialized beef breeds imported (from Northern Ireland) and crossbred animals from their crosses. With the aim of studying the growth and development of purebred pigs of large white and Landrace breeds and crossbred animals from their reciprocal combinations in terms of plant LLC “freedom farm Bacon” was formed four groups of 15 animals each. Animals of all experimental groups were kept in group cages on slowy floor with free access to sokovich drinkers and samogon. Feeding was carried out rations balanced for a wide range of nutrients to meet the age requirements. Monthly animal individually resolved and taken measurements. Based on the weightings were calculated the average body weight for each group, the absolute, average and relative gains, indexes physique. Summarizing the results of the research it is possible to draw the following conclusions.
1. The pigs of Landrace had a higher growth energy, which gave them an advantage in live weight, which was more significant with age.
2. By weight, the obtained effect of heterosis in crossbred gilts and direct and inverse variations crossing. Most likely the difference in live weight was at the age of 6 and 7 months in favor of crossbred animals on both the source rocks.
3. The linear parameters are set more significant differences between breeds Landrace and large white crossbred animals had mostly intermediate character change performance measurements and indices of body.
4. Landrace had a long torso and is 6.2 4.8 cm superior to their counterparts of large white breed, however, was inferior to the depth of the chest.
5. Crossbred gilts of both research groups on linear measurements and indexes of body composition were mainly of an intermediate nature of inheritance with a deviation in the direction of the parent species.