Animals and source of data The data were accumulated from a research project on “conservation of Black Bengal goat as the potential resources in Bangladesh at Bangladesh Agricultural University campus”. The research period was from January to September, 2008. A total of 10 breeding bucks were used as an experimental animal. Semen was collected from each buck twice in a week. Preliminary sorting and checking of data were carried out at the Department of Pathology, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh.
Feeding and management of animals Feeding and management systems were more or less uniform throughout the year. The animals had access to regular exercise to avoid fattiness and laziness. These bucks were vaccinated against PPR. The experimental bucks were previously tested for breeding soundness. No remarkable abnormality was reported from any buck.
Semen collection Semen was collected by artificial vagina (AV) method twice in a week. The time of semen collection was in the morning at 8.30 am. The buck was allowed usually at least one false mount. AV was served only when the buck mounted with erect penis. The semen was obtained in a graduated vial previously assembled with the rubber cone. After collection, semen held in tube was put into water bath at 37°c until going for further handling.
Semen evaluation The routine evaluation of fresh semen was done immediately after collection. The volume, color, motility, mass activity, normal sperm count (%) and head-tail abnormalities and their counting % were recorded. The volume of semen was recorded by reading the graduated mark of the collection vial. The color of the semen was observed in collection vial with necked eye and recorded as milky to creamy. To observe the mass motility, one drop of semen was placed on a pre-warmed (+37°C) slide covered with cover slip and examined at higher magnification (100X). The mass activity was scored into four scales (+=no mass activity; ++=slow wave motion without forming any waves; +++= rapid wave motion with formation of eddies at the end of waves; ++++=very rapid wave motion with distinct eddies).
Semen evaluation The routine evaluation of fresh semen was done immediately after collection. The volume, color, motility, mass activity, normal sperm count (%) and head-tail abnormalities and their counting % were recorded. The volume of semen was recorded by reading the graduated mark of the collection vial. The color of the semen was observed in collection vial with necked eye and recorded as milky to creamy. To observe the mass motility, one drop of semen was placed on a pre-warmed (+37°C) slide covered with cover slip and examined at higher magnification (100X). The mass activity was scored into four scales (+=no mass activity; ++=slow wave motion without forming any waves; +++= rapid wave motion with formation of eddies at the end of waves; ++++=very rapid wave motion with distinct eddies).
Acrosome, midpiece and tail were evaluated by using Rose Bengal stain. A one drops of buffer placed on a clean, dry glass slide. One drop of semen was added in buffer. It was spreaded by covering with another slide and it was dried in the air. The smear was stained with Rose Bengal stain for 3-5 minutes, then it was rinsed with distilled water to remove excess stain and the smear was dried in the air. The slide was placed on the stage of microscope and counted under 40×. Spermatozoa having any deformity, such as bent tail cork screw tail, coiled tail etc were considered to be abnormal. At least 100 spermatozoa from individual smear were examined under 40× and recorded.
Statistics The data collected from the experiment and the findings were entered into Microsoft Excel spread sheet. Then, the mean and standard deviation (mean ± SD) of age, ejaculate volume, sperm motility, mass activity, and abnormal spermatozoa were figured out from the original data.