Forage cactus as a substitute for ground corn in sugarcane-based diets for lactating dairy cows.

The objective of this study was to evaluate the effects of replacing ground corn meal with forage cactus Opuntia stricta (Haw.) Haw. in sugarcane-based diets on the performance of lactating dairy cows. Ten Holstein cows, with an average milk yield of 20 ± 0.9 kg day⁻¹, body weight of 592.5 ± 24.3 kg, and 15.5 ± 2.5 weeks in milk, were used and distributed into two simultaneous 5 × 5 Latin squares. The treatments consisted of levels of replacement of ground corn meal with forage cactus (0, 25, 50, 75 and 100%). Replacement linearly reduced (P < 0.05) the intake of dry matter, crude protein, organic matter, non-fibrous carbohydrates and total digestible nutrients. Apparent nutrient digestibility was not affected by the replacement (P > 0.05). Milk yield not corrected to 3.5% fat decreased linearly (P = 0.002) with increasing replacement levels (18.33 and 16.25 kg day⁻¹ at 0 and 100%, respectively), whereas milk fat content increased linearly (P = 0.035) from 3.65 to 4.14%. Fat-corrected milk yield (3.5% FCM; 18.46 kg), as well as milk protein (3.42%), lactose (4.42%), total solids (12.61%) and feed efficiency (0.99 kg fat-corrected milk per kg of dry matter intake), were not affected (P > 0.05). Forage cactus can partially replace corn in diets for dairy cows fed sugarcane-based diets. However, replacing corn with forage cactus reduces dry matter and nutrient intake and milk yield not corrected for fat, although it results in significant increases in milk fat content.