Ammoniated wheat straw utilization during late ewe pregnancy

Raúl Meneses R.1, Randall D. Wiedmeier2, Lyle G. McNeal2 y Jeffrei L. Walters2

Treated straw with ammonia was evaluated on pregnant ewes. In the first experiment, 78 pregnant ewes were used. Half of the ewes were offered ground and mixed diets of alfalfa hay, corn silage, minerals and vitamins and grass hay (Daclylis sp, Bromus sp and Poa sp) (C-1) and the other half received the same diet using treated straw instead of hay (T-1). In the following season 66 pregnant ewes were used and randomly distributed in six stockyards. Half of the ewes were offered traditionally treated straw (C-2) and the other half received hidrated ammoniated straw (T-2). AII ewes, in addition received 0.907 kg/day of a supplement of alfalfa hay, corn silage, minerals and vitamins. Both experiments were evaluated by measuring intake, body weigh, birth weigh and wool production. The food intake in the first experiment was not different (P > 0.05). Daily gain was reduced in T-1 (P < 0.05), 0.15 vs. 0.12 kg/day. The wool production was reduced in T-1 (P< 0.05), 3.7 vs 4.3 kg/ewe. Body birth weight was not affected by T-1 (P =0.431). In the second experiment T-2 intake was higher than C-2 (P < 0.01). The daily gain was higher for T-2 (P < 0.05), 0.128 vs. 0.205 kg/day. The birth weight was similar (P = 0.874).The wool production increased 13% in T-2 (P < 0.05). Ammoniated straw may be a good resource for pregnant ewe, specially if it is hydrated before treatment, but may induce Iimitation in wool growth.

Keywords: ewe pregnancy, treated straw, hydrated straw.
1 Campo Experimental Los Vilos, Casilla 40, Los Vilos, Chile.
2 Animal, Dairy and Veterinary Sciences Department, Utah State University, Logan. UT 84322-4815, E.U.A.