Replacement of sorghum silage (Sorghum bicolor L. Moench) with a columnar cactus (Pilosocereus gounellei (A. Weber ex K. Schum.) Byl ex Rowl.) on diets of lactating dairy cows

Five lactating Brown-Swiss cows averaging 520 kg of body weight (BW) and 15 kg of milk yield were assigned to a 5 x 5 Latin square to study the effects of replacing sorghum silage (Sorghum bicolor L. Moench) with a columnar cactus known as xiquexique (Pilosocereus goulzellei (A. Weber ex K. Schum.) Byl ex Rowl.) on animal performance and apparent digestibility of nutrients. The experimental diets contained (DM basis): 0, 12.5, 25, 37.5, or 50% of xiquexique. Each experimental period lasted 17 days (10 days for diet adaptation and 7 days for sample collection). Intake of dry matter (DM) expressed as amount (kg/d), as percentage of BW, or as metabolic weight (g/kg(0.75)) were 15.21 kg/d, 2.83% of BW, and 136. 10 g/kg(0.75) and did not change by replacing sorghum silage with xiquexique in the diet. Similarly, intake of organic matter (OM), crude protein (CP), and total carbohydrates (TCH) did not differ and averaged 13.64, 1,64, and 11,48 kg/d across diets, respectively. However, intake (kg/d) of neutral detergent fiber (NDF), ether extract (EE), and total digestible nutrients (TDN) all decreased linearly (P < 0.01) while the opposite was observed for non-fiber carbohydrates (NFC) by replacing sorghum silage with xiquexique in the diet. No significant differences in the apparent digestibility of DM (DMAD), organic matter (OMAD), crude protein (CPAD), ether extract (EEAD), neutral detergent fiber (NDFAD), and total carbohydrates (TCHAD) were observed by increasing the dietary proportions of xiquexique. Milk yield averaged 14.80 kg/d and also did not differ among treatments in the present trial. Following the same trend, milk composition and feed efficiency (kg of milk yield/kg of DM intake) were unaffected by increasing the levels of xiquexique in the diet.