Seasonal variation in semen quality of dorper rams using different collection techniques

[摘要] The aim of the study was to evaluate the seasonal variation in semen quality ofDorper rams using different semen collection techniques. The Dorper breed wasused because of its renowned adaptability, hardiness, veld utilization, goodmothering ability and high general global demand. The study was carried out onthe University of the Free State campus, in Bloemfontein, South Africa fromJanuary 2012 to January 2013 (summer to summer). Eleven mature Dorperrams, recording a mean body weight of 69.6±9.2 kg and mean age of 18±4.7months were used in this trial. The rams were clinically examined for breedingsoundness prior to the study with the aid of a veterinarian, and then randomlydivided into two groups. A group of 6 rams were trained for semen collection withthe aid of the AV, while in the remaining 5 rams semen were collected using theEE. Two Dorper ewes were used as teasers during the training and for the entireduration of the trial in the AV group. A general management schedule for diseaseprevention was followed with water provided ad libitum throughout the trial and allrams fed a 2.5 kg maintenance diet (8.5MJ ME/kg) per day - the nutritionalregime thus remained uniform and constant throughout the trial. A laboratory toperform the semen evaluation was set up adjacent to the semen collection area.Semen was collected weekly (Thursday) with the aid of the artificial vagina (AV)or electra-ejaculator (EE). Semen ejaculates were evaluated for semen volume,semen colour, semen pH, sperm wave motion, sperm motility, sperm cellconcentration, sperm viability and morphology. Other parameters evaluatedincluded libido (sex drive), body weight, body condition score, body temperature,scrotal circumference and scrotal volume. Climatological information for the studyarea during the experimental period, was obtained from the· Department ofAgrometeorology (UFS weather station).The effect of method of semen collectiontechnique (AV vs EE) and the seasonal changes on the above mentionedparameters were compared over seasons. The seasons were laid out as summer(December, January and February), autumn (March, April and May), winter(June, July and August), and spring (September, October and November). Thesemen and body parameter results were statistically analyzed with the aid of thePROC GLM procedures of SAS (1995). Parameters were considered significantat P

[发布机构] University of the Free State