To evaluate economic effects and health and performance of the general cattle population after exposure to cattle persistently infected (PI) with bovine viral diarrhea virus (BVDV) in a feedlot. 21,743 high-risk calves from the southeastern United States. PI status was determined by use of an antigen-capture ELISA (ACE) and confirmed by use of a second ACE, reverse transcriptase-PCR assay of sera, immunohistochemical analysis, and virus isolation from sera. Groups with various amounts of exposure to BVDV PI cattle were used. After being placed in the feedlot, identified PI cattle were removed from 1 section, but PI cattle remained in another section of the feedlot. Exposure groups for cattle lots arriving without PI animals were determined by spatial association to cattle lots, with PI animals remaining or removed from the lot. 15,348 cattle maintained their exposure group. Performance outcomes improved slightly among the 5 exposure groups as the risk for exposure to BVDV PI cattle decreased. Health outcomes had an association with exposure risk that depended on the exposure group. Comparing cattle lots with direct exposure with those without direct exposure revealed significant improvements in all performance outcomes and in first relapse percentage and mortality percentage in the health outcomes. Economic analysis revealed that fatalities accounted for losses of $5.26/animal and performance losses were $88.26/animal. This study provided evidence that exposure of the general population of feedlot cattle to BVDV PI animals resulted in substantial costs attributable to negative effects on performance and increased fatalities.

The study has stated that heifer replacements, from the date of birth to 18 months, got through transplantation of frozen-defrosted embryos were not inferior to and in many cases superior to the heifers of their age but got through traditional reproduction. Transplant first-calf heifers have a high level of milk productivity which amounts to 7536,10 kilos, with 3,62% of fat and 3,23% of protein. Thus they provide a good selection material for new generation champions to be chosen among them and for being used as mothers of bulls for service

Possibility of increasing of meat productivity of ducklings of Temp cross after application of duck parental forms of German selection was studied in the conditions of the Republic of Belarus. In course of study there was revealed the dynamics of changes of live weight and feed expenses for live weight gain of linear and hybrid ducklings; as well as their meat qualities were determined. In course of studied there were used linear and hybrid ducklings obtained after crossbreeding of parental forms of Belarusian and German crosses of Peking breeds. There were formed 8 groups of one-day old ducklings. In the father's line the first (control) group was presented by pure bred line T1 of Temp cross; in the second group – by hybrid NT1 x T1, obtained after the direct crossing of male ducks of NT1 with female ducks of T1 lines; in the third group – by hybrid T1 x NT1, obtained after the backcrossing of male ducks of T1 with female ducks of NT1 lines; in the fourth group the combination NT1 was obtained by NT1 x NT1. In fifth group the maternal line was presented by pure line of T2 Temp cross (control); the sixth group was presented by hybrid T2N x T2 obtained after direct crossing of male ducks of T2N line with maternal ducks of T2 line; in the eighth group the combination T2N was obtained by T2N x T2N. Research results showed that application of Germal ducks in schemes of crossbreeding rendered the positive influence on live weight increasing of ducklings of father's line. In the carcasses of hybrid ducklings of all studied crossbreeds there was stated the decreasing number of skin with adipose layer and increasing number muscles including the pectoralis