Ammonia treatment for sugar cane harvest residues. Heifer performance

A total of 300 crossbred Holstein heifers of an ge liveweight of 196 kg were housed in rustic facilities under drylot conditions, according to a random block design with two treatments and three replications each. Treatments consisted of ad libitum supply of cleaning centre residues (sugar cane straw) treated with ammonia and 2 kg of a supplement with 75% dry matter, 13% crude protein (N x 6.25) and 8.8 MJ of metabolizable energy/kg of dry matter (experimental) and ad libitum untreated residues plus 2 kg of a supplement with 70% dry matter, 17.6% crude protein (N x 6.25) and 7.9 MJ of metabolizable energy/kg of dry matter(control). Residue consumption on a humid base (7.0 and 9.5 kg), of dry matter intake (2.6 and 3.0 kg/100 kg liveweight) and daily liveweight gains (206 and 402 g/animal), were higher and dry matter conversion (26.2 and 16.4 kg/kg liveweight gain) crude protein conversion (2.50 and 1.96 kg/kg of liveweight gain) and metabolizable energy conversion (189 and 129.7 MJ/kg of liveweight gain) were better in the treated residues. The ammonia treatment of cleaning centre residues and the use of richer energy supplements with lower NPN concentration to improve performance of stabulated heifers under drylot conditions, is suggested.