Effects of different extenders and storage temperatures on longevity of small East African goat (Capra hircus) semen

Abstract

Goat production is central to resource-poor rural livelihoods in the tropics. However, it is constrained by high inbreeding levels and poor access to good quality breeding bucks. In this study, semen extenders differing in egg yolk and energy level were compared in their ability to maintain liquid semen from a tropical goat breed, when stored at physiological (37 °C) or refrigerator (4 °C) temperature. Semen was collected weekly for nine weeks from seven bucks of the Small East African goat breed, diluted in three extenders and incubated at 37 °C or 4 °C for 24 h. The semen parameters: viability, motility and morphology were better preserved when semen was incubated at 4 °C compared to 37 °C across all extenders. Sperm motility after 24 h at 4 °C was 50.4 ± 5.5%, 50.4 ± 6.2% and 54.3 ± 5.4% for Extender 1 (high glucose, 18% egg yolk), Extender 2 (low glucose, 2.5% egg yolk) and Extender 3 (low fructose, no egg yolk), respectively. Extender 2 maintained significantly higher viability values (67.7 ± 2.5%) at 24 h compared to Extenders 3 (59.3 ± 2.1%) and 1 (46.7 ± 4.2%). Normal morphology after 24 h (88.1 ± 3.1% at 4 °C and 85.6 ± 3.1% at 37 °C) fell within the acceptable range for good quality semen. Acceptable quality was maintained within 8 h and up to 24 h from collection for non-frozen goat semen stored at 37 °C and 4 °C temperature, respectively. These results imply that Small East African goat semen diluted in low or non-egg yolk based extenders and stored at refrigerator temperature can be valuable for artificial reproduction of native goats on low resource capacity farms in developing countries