Access to pasture in an outdoor housing system affects welfare indicators and improves rooster sperm quality in two native Mediterranean breeds

Abstract

The aim of the present work was to examine the influence of access to pasture in an outdoor housing system on rooster sperm quality and response to cryopreservation and to examine the possible correlation between values for sperm quality variables and welfare indicators. Two groups of Black-barred Andaluza and Red-barred Vasca roosters were housed in an outdoor system, with one group given daily access to a grazing area containing plant species that typically grow on uncultivated Mediterranean land. Semen was collected once per week from each group, and the following sperm quality variables were assessed: sperm volume, appearance, concentration, motility, membrane integrity, acrosome integrity, and morphological abnormalities. In addition, two welfare indicators were examined: the heterophil/lymphocyte (H/L) ratio, and the duration of tonic immobility (TI). Ejaculates from the birds with access to pasture had higher percentages of sperm showing progressive motility (P = 0.019), and returned a higher motility index (P = 0.035). Unexpectedly, the H/L ratio was also higher in these birds. Virtually no differences were seen between the treatment groups with respect to sperm quality after freezing-thawing, although the semen of the Red-barred Vasca birds with access to pasture did show a higher percentage of progressive motility (P = 0.023) than the birds of the same breed with no such access. Significant correlations were detected between the H/L ratio and sperm motility (r=0.420, P = 0.038), the sperm motility index (r = 0.526, P = 0.002), and progressive motility (r=0.467, P = 0.003). No differences were seen between the treatment groups with respect to the duration of TI. In conclusion, access to pasture improved fresh sperm motility.