Behavior and milk production of buffalo cows as affected by housing system

To verify the effect of 2 housing systems (with and without a pool and an ample outdoor lot) on behavior and milk yield, 45 lactating buffalo cows were group-housed in a free stall open-sided barn with concrete floor where they received 10 m(2)/head as space allowance (group NP); 43 cows were group-housed in a similar barn, but had access to an outdoor yard (36 m(2)/head) and a concrete pool of 208 m(2) (group WP). Animals were subjected to 8 sessions of instantaneous scan sampling at approximately 10-d intervals. Behavioral variables were expressed as proportions of subjects observed in each category of posture and activity. In addition, rapid behaviors such as agonistic, social, and reproductive interactions, social licking, and self-grooming were recorded continuously. These variables were expressed as number of interactions per animal. At the end of each hour of observation, temperature and relative humidity were recorded. In WP the proportion of animals observed wallowing was 0.476 +/- 0.034, whereas lower proportions were observed standing (0.389 +/- 0.029) or lying (0.141 +/- 0.021) outside the pool. In NP the proportions of animals observed standing and lying were 0.452 +/- 0.042 and 0.548 +/- 0.042, respectively. A significant relationship between mean temperatures recorded on observation days and proportion of animals in the pool was observed (r(s) = 0.41). Fewer animals from group WP were observed idling compared with buffaloes from group NP (0.44 +/- 0.024 vs. 0.509 +/- 0.024, respectively), whereas more WP animals were involved in investigative activities than NP cows (0.099 +/- 0.009 vs. 0.042 +/- 0.009, respectively). A greater number of social interactions (sniffing and nuzzling) and social lickings were observed in group WP than in group NP (0.120 +/- 0.010 vs. 0.067 +/- 0.010, and 0.151 +/- 0.018 vs. 0.090 +/- 0.018, respectively). The WP buffalo cows had a greater milk yield than NP cows (11.73 +/- 0.31 vs. 10.78 +/- 0.28 kg/d, respectively), whereas no differences