The effect of caustic soda treatment and protein supplementation of Paspalum dilatatum hay on intakes and live weight changes of cattle

Abstract

Mature Paspalum dilatatum hay was baled untreated, or sprayed with a solution supplying 12 g N and 1,2 g S/kg forage, as urea and NaHSO₄, respectively, with and without the addition of caustic soda (40 g NaOH/kg forage). Sprayed forage was left in a moist condition in windrows for 24 hours before tedding and baling. Forages were chopped into 5-10 cm length and offered ad lib. to 40 Hereford streers and heifers housed in individual stalls and allocated to five treatments as follows: A) untreated hay; B) N + S; C) N + S + 300 g meat meal/head/day; D) N + S plus sodium hydroxide; E) N + S plus sodium hydroxide plus 300 g meat meal/head/day. Animals on treatment A suffered muscular trembling and ataxia and were removed from the trial. Liveweights were recorded twice weekly over 44 days and liveweight changes calculated as the coefficients of liveweight regressed against time. Liveweight gains did not differ significantly, being 471, 474, 547 and 525 g/head/day on treatments B, C, D and E, respectively. Voluntary dry matter intakes were higher on treatments D and E than on treatments B and C (D, E > B, C; P<0,05), being 4,18; 3,93, 3,62 and 3,73 kg/head/day, respectively. The in vivo digestibility of organic matter in the dry matter was similar on all treatments (52%).