Essentially, nutrition affects the fertility of dairy cows The incidence of functional forms of subfertility is constantly increasing, especially due to disturbances ill the balance of degradable proteins and energy ill forage. This research Was Undertaken oil one hundred primiparous Frisian dairy cows, divided into two groups (group A, n=50 group B, n=50) in the early breeding period. 44(th) to 52(nd) clay postpartum. Average lactation in both groups was 32 litres of milks. Gynaecological findings in groups A were: proestrus 5. oestrus 3, dioestrus 6. cystic ovarian disease (COD) 6, an(;estrus 24, endometritis 4 and pyometra 2. Findings in groups B: proestrus 6, oestrus 5, dioestrus 6, COD 5, anoestrus 21. endometritis 4. pyometra 3. All cows with clinically diagnosed with endometritis, pyometra and COD were treated twice or three times with synthetic prostaglandin F2alfa analogues. Over three weeks the cows front groups A were fed extensively, ab libitum, and the Feed was composed of corn silage (50% less than in the feed for group B) lucerne haylage, lucerne hay and 10% concentrated type food without soybean. maize and sunflower cake, with barley and cca 70-80% bran. Cows from groups B were fed with standard farm concentrated mixture for dairy cows meal of 34.5 kg of food was composed of corn silage, lucerne haylage, lucerne hay and c 19% concentrated type food, with 20.03 kg of dry matter and 16.3% proteins. The concentrated type food was composed of soybean (6%), maize (20%), sunflower cake TMR Camisan (5%), bran (50%) and barley (18%). Three weeks later the gynaecological findings ill groups A: B were: proestrus 19:7, oestrus 7:6, dioestrus 20:6. COD 0:7, anoestrus 3:20, endometritis 1:3, pyometra 0: 1. Within one hundred days from calving 29 cows from group A (58%) conceived. with average service time of 94 days, and 14 cows (28%) front group B conceived, with average service little of 96 days. Up to the 150(th) day of lactation 47 cows from group A (94%). and 36 (72%) from the Control groups conceived. Average lactation during the three weeks of research was 30 lures in group A, and 3 1 litres of milk in group B. In the beginning of the research, the body condition score of the cows was between 1.5 and 2.5 points. Oil the 100(th) day after calving the cows from group B were unequal in condition (BCS from 1.5 to 3.25, average 2.03 points), and cows from group A were equal in condition with all average of BCS 2.93. Oil the 15011 day after calving the average BCS of cows From group A was 3.04, and cows from group B 2.69. Cows. fed with corrected nutrition with natural high rumen-degradable proteins showed good reactions to the procedures of introduction to breeding. The goal of this study was to compare the effects of two different regimes of nutrition on the beginning of reproduction and on reproductive efficiency. i.e, to prove the better effect of nutrition rich in rumen-degradable proteins compared to standard farm mixture for nutrition of diary cows, in lactation.
