LAUSR

ABSTRACT The effect of two housing systems during the fattening period on productive performance of lambs from different hair-type sheep breeds in southeastern Mexico was evaluated. Effects of housing system (raised-slatted floor cages (RFC) vs. floor pens (FP)), year (2009, 2012 and 2013) and season of the year (rainy vs. dry) on average daily gain (ADG), weights adjusted to 60 (P60) and 90 (P90) days post-weaning were evaluated. Data from 1213 lambs collected on the farm over a period of three years were analysed. The ADG, P60 and P90 were affected (P < .01) by the housing system, year and the housing system × year interaction. The season was not a significant source of variation. Lambs housed in RFC were heavier (ADG 306.5 ± 2.69 g, P60 33.2 ± 0.16 kg, P90 42.4 ± 0.24 kg) than those in FP (ADG 269.4 ± 4.24 g, P60 30.9 ± 0.25 kg, P90 39.0 ± 0.38 kg) (P < .01); however, the significant interaction housing system × year suggests that productive performance of lambs may vary between years, despite the housing system. It was concluded that productive performance of hair lamb was affected by housing systems, year and their interaction.