No abstract

Littermate pairs of crossbred boars, barrows and gilts were used to study the effects of an artificially extended photoperiod during decreasing daylength on puberty in boars and on weight gain and feed efficiency. Libido scores of the boars exposed to the extended photoperiod were higher (P < .01) than those of controls at 24 and 26 weeks of age. At 26 weeks of age, semen had been collected from 74% of the boars on supplemental light but from only 26% of the controls. Lighting treatment did not affect semen quality. The number of ejaculates previously collected did affect semen quality. Motility and total sperm per ejaculate increased with increasing ejaculate number, while the percentage of abnormalities appeared to decrease. A second group of boars was delayed in the development of mating behavior, perhaps because of inadvertent consumption of Gibberella zeae-infected corn. The extended photoperiod did not exert a beneficial effect on weight gain or feed efficiency of boars, barrows or gilts.

No abstract

GnrrNnrnc, L. G. nNo ManoNs, J. P. I 981 . The effect of a 15-h photoperiod on reproductivefunctioninboards at2,3,4 or5monthsof age. Can. J. Anim. Sci. 6l:925-934.The effects of supplemental lighting in stimulating reproductive function in prepuberal boius were studied using littermate boars divided equally into four groups (n : 9). All boarsreceivednatural daylighr(9.2 12.8h)until 2moofage,followedbyarrificiallight given daily according to the following schedule: boars wereexposed to a 15-hphotoperiod beginning at the age ot 2 (group I); 3 (group II); 4 (group III) or 5 mo (group IV). Libido scores of the four groups increased with age (P < 0.001 ). Seminal plasma protein (P < 0.01) and zinc concentration (P < 0.05), sperm-rich concentration, sperm-rich volume, total semen volume and total viable sperm increased (P < 0.05) with age in all four groups. The photoperiod treatment had no effect on semen quality on a per ejaculate basis between the groups; 15 h of light per day was not effective in accelerating the onset of puberty when administered from 2, 3, 4 or 5 mo of age onward.Dans cette 6tude sur des verrats pr6pub6raux, l'utilisation d'un 6clairage prolong6 d 6t6 6valu6e comme moyen de stimuler leur efficacit6 de reproduction. Chacun des groupes avait la m6me composition quant i l'origine maternelle des verats. Le programme d'dclairagea6t6 lesuivant: naturel (9.2-12.8h) jusqu'dl'dgede2mois, l5hdelumidre

Changes in body weight, sperm concentration and testicular volume were monitored for a 13-lunar month period in seven laboratory-housed adult male Macaca fascicularis. No significant change was noted in body weight or sperm concentration between periods of maximal and minimal mean values nor between periods standardized for comparison between the three parameters. Testis volumes were significantly greater during the months of July through early September and during the standardized period of May through July than during January through March and the standardized interval October through January.