Effects of physical form of starter and forage provision to young calves on blood metabolites, liver composition and intestinal morphology.

This study evaluated the effects of physical form of starter feed and forage provision on the performance, blood metabolites, liver composition and intestinal morphology of dairy calves. Individually housed calves ( n = 52; body weight = 41.5 ± 2.5 kg) were randomly allocated ( n = 13 per treatment) to one of the following four treatments: (i) ground starter feed (GS; mean particle size = 0.72 mm in diameter), (ii) textured starter feed (TS; mean particle size = 3.61 mm in diameter, including steam-flaked corn and barley), (iii) pelleted starter feed (PS; mean particle size = 4.53 mm in diameter) and (iv) ground starter feed with chopped alfalfa hay (GS + AH; mean particle size = 1.02 mm in diameter). The calves fed GS + AH diets had greater (p < 0.01) starter intake, final body weight and average daily gain compared with the other groups, while GS and TS groups both had greater (p < 0.01) starter intake than the PS group. Feed efficiency was found to be better (p < 0.05) in the TS group than in the GS or PS group, but not different from the GS + AH one. Compared with the other groups, the GS + AH group had the highest (p < 0.01), while the PS one had the lowest (p < 0.01) concentrations of blood glucose and triglyceride. The calves fed GS + AH had the highest blood concentrations of total protein, globulin, triiodothyronine (T3), thyroxin (T4), T3 : T4 ratio (p < 0.05) and levels of fat and glycogen in the liver (p < 0.01) compared with the other groups. The highest (p < 0.05) liver glycogen contents were observed in the GS + AH and TS groups. The duodenum, ileum and jejunum in the calves fed GS + AH exhibited a greater muscle layer thickness (p < 0.05) compared with the other groups. Based on the results obtained, the addition of dietary forage to starter diets positively influenced performance, liver composition and intestinal morphology in developing calves. [ABSTRACT FROM AUTHOR]