The objective of this work was to evaluate the effect of photoperiod on food intake, and milk production and composition (fat, protein, lactose, total solids) and somatic cell number. Seven Bergamasca ewes were submitted to a short photoperiod (12 hours light:12 hours dark), and eight Bergamasca ewes were submited to a long photoperiod (18 hours light:6 hours dark), during the last four weeks of pregnancy, and for three months of lactation. Results were compared by t test for two independent samples. Food intake was evaluated daily for each pen containing two ewes, and did not differ between treatments. Mean food intake was 4.48 kg under the short photoperiod, and was 4.40 kg under the long photoperiod. Differences between photoperiods were not significant for milk production and levels of protein, lactose and total solids considering 84 days of lactation. Mean percentage fat of 5.57% for the short photoperiod was greater than that 5.21% for the long photoperiod. In weekly results analyses, it was observed that in the second and fourth week of lactation, milk production of the ewes under long photoperiod was higher. Somatic cells number did not differ between photoperiods and stayed low during all lactation period. The greatest number of hours of light stimulated milk production in the first month of lactation, mainly in fourth week. Percentages of fat and total solids are lower in periods of greater milk production.
sheep; light; lactation
