Effects of replacing wheat bran by pistachio skins on feed intake, nutrient digestibility, milk yield, milk composition and blood metabolites of dairy Saanen goats.

The objective of this study was to investigate the effect of pistachio skins (PiS) as a replacement of wheat bran on feed intake, nutrient digestibility, milk yield, milk composition and blood metabolites of dairy Saanen goats. Eight multiparous lactating Saanen goats (55 ± 7.2 days post-partum, 45 ± 2 kg body weight) were randomly assigned to one of the four dietary treatments arranged in a replicated 4 × 4 Latin square design. The dietary treatments were 1) 0 g/kg PiS and 210 g/kg wheat bran in the TMR (0PiS), 2) 70 g/kg PiS and 140 g/kg wheat bran in the TMR (7PiS), 3) 140 g/kg PiS and 70 g/kg wheat bran in the TMR (14PiS) and 4) 210 g/kg PiS and 0 g/kg wheat bran in the TMR (21PiS). The trial consisted of four 21-day periods, each composed of 14 days adaptation and 7 days data collection. Dry matter intake (p < 0.05) and crude protein digestibility (p < 0.01) increased linearly with increasing PiS proportions in the diet. Increasing the proportion of PiS in the diet caused a quadratic increase in apparent digestibility of dry matter (p < 0.05), and tended (p = 0.05) to increase quadratically organic matter, and ether extract digestibility. Replacing wheat bran with PiS in the diet had no effects on milk yield, whereas milk fat concentration increased linearly (p < 0.01) with increasing inclusion of PiS in the diet. As the dietary proportion of PiS increased, ruminal pH tended (p = 0.07) to increase linearly, whereas ammonia-N concentration declined in the rumen. Plasma concentrations of glucose and BUN remained unaffected, whereas triglycerides (p < 0.05) and cholesterol (p < 0.01) concentrations increased linearly with increasing inclusion of PiS in the diet. It was concluded that PiS based on local ingredients can successfully replace wheat bran in diets of dairy goats without detrimental effects on feed intake, nutrient digestibility and milk production.