Effects of partial replacement of berseem hay by corn stalk with or without calcium salts of fish oil on rumen fermentation, productive and reproductive performance of early lactating cows.

摘要

Ninety early lactating Holstein dairy cows were assigned among 6 groups (15 each) to investigate the effect of dietary partial replacement of Berseem Hay (BH) by Corn Stalk (CS) with or without Calcium Salts of Fish Oil (CaSFO) supplementation on ruminal fermentation characteristics, productive and reproductive performance as well as on some blood serum parameters from 1st week after calving through 12 weeks postpartum. Three experimental diets were formulated without or with CaSFO supplementation to be fed to 6 cows groups (15 per each). Cows fed on 10 or 20% of CS diets loss more body weight, suffering from more negative energy balance and eat less dry matter than control, however, milk-to-feed ratio improved by about 2.5 and 3.8%, respectively compared with control. On the other hand CaSFO supplementation reduced body weight loss, improved feed intake, lessened the negative energy balance and slightly improved milk-to-feed ratio by about 1.3, 0.0 and 0.6%. CS significantly affect ruminal fermentation by production more propionate and less acetate compared with control while, fat supplementation had no significant effect on the rumen fermentation characteristics. CS (10 or 20%) feeding reduced milk production across the experiment by about 1.9 and 5.6%, respectively when compared with control, while milk production improved with fat supplementation. However, either CS or CaSFO supplementation had no significant effect on milk composition. Moreover, CS feeding had no effect (p>0.05) on serum glucose and non-esterified fatty acids at 8th or 12th week postpartum. While CaSFO increased (p>0.05) serum glucose concentration and mostly non significantly reduced NEFA concentration. Also, CS had no effect on the reproductive performance and fat supplementation showed a trend toward improving reproductive performance as indicated by increased percentage of pregnant cows in the first 28 days of breeding. It could be concluded that CS inclusion up to 20% with CaSFO supplementation (11 g kg-1 diet) may offer a potential management practice to improve productive and reproductive performance in dairy cattle.