In this study, the effects of different fat supplements in starter diets were investigated on feed intake (FI), blood metabolites and rumen parameters of neonatal dairy calves. Sixty neonatal Holstein suckled calves (12 for each treatment ; body weigh 39.5 ± 0.3 kg) after receiving 6 L of colostrum were allocated to 1) Starter diet without fat supplement (control), 2) Starter diet with 3% palm fat, 3) Starter diet with 3% soybean oil, 4) Starter diet with 3% tallow and 5) starter diet with 3% mixed oils (1% palm fat, 1% soybean oil, 1% calcium salt of fish oil). Calves fed with 4 L/d of whole milk from d 3 to 20, 5 L/d from d 21 to 25, 6L/d from d 26-45, and 3 L/d milk from d 46 to 49. Feed intake, body weight (BW), digestibility, blood cells count and metabolites, rumen VFA, ammonia and pH, fecal score and feeding behavior was measured. The result indicated that feed intake, average daily gain (ADG), feed efficiency(FE) and body weight were significantly affected by treatments ( P 0.01). Compared with control inclusion of palm fat and tallow had no significant effect on FI, ADG and BW however. Tallow supplementation decreased feed efficiency. Soybean oil supplementation had no effect on DMI but its addition improved ADG, FE in total periods (pre-weaning and post-weaning). Farther soybean oil increased body depth in post-weaning ( P 0.05). The mixed oil in starter diet resulted reduced DMI, ADG, BW and FE in contrast to fat supplemented and supplemented groups ( P 0.01). Number of blood cells, rumen VFA, ammonia and pH, digestibility and the fecal score of feedstuffs did not differ among treatments( P 0.05). Experimental diet showed no significant effect on blood metabolism in pre-weaning period, whereas palm fat addition increased HDL cholesterol in post-weaning period ( P 0.05). Calves fed soybean oil and tallow spent more time for eating compared to calves fed control diet, palm fat and mixed oil. It is concluded that addition soybean oil in starter diet improved ADG, BW, glucose and FE with on any negative effect on FI. Palm fat and tallow had no effect on performance but mixed oil supplementation reduced FI and consequently BW, ADG and FE. Keywords : Palm fat, Soybean oil, Tallow, Fish oil, Calve
