The study of effects of feed bunk space and forage particle size on digestibility and fecal properties in Holstein female calves

The objective of this study was to evaluate the effects of feed bunk space and forage particle size on feed intake and nutrient digestibility in growing Holstein female calves. Fourty Holstein female calves with an average age of 8-12 months (295.6 ± 32.8 kg) were used in a 2×2 factorial change-over design (with four treatments, four periods and four stalls), in which 10 calves were allocated to each stall. The current experiment lasted 4 months as one month allocated to each period. The experimental treatments were included: 1) 24 cm of feed bunk space and average forage particle size of 4.6 mm (24/fine); 2) 24 cm of feed bunk space and average forage particle size of 7.1 mm (24/coarse); 3) 48 cm of feed bunk space and average forage particle size of 4.6 mm (48/fine); 4) 48 cm of feed bunk space and average forage particle size of 7.1 mm (48/coarse). The results of this study showed that the apparent digestibilities of DM, CP and NDF for the 48/Coarse treatment was the highest, the treatment of 24/Coarse had an intermediate state, and for the treatment of 48/fine and 24/fine were the lowest. Also, apparent digestibilities of DM, CP and NDF were higher for treatments including coarse forage particles than treatments with fine forage particle size. Finally, it seems that feeding growing Holstein heifers with diets containing coarse forage particle size could result in better nutrient digestibility.