Effect of Different Packages and Freezing/Thawing Protocols on Fertility of Ram Semen |
| |
| Authors: | AB Nordstoga L Söderquist T Ådnøy H Paulenz |
| |
| Institution: | Team Semin, Oslo, Norway;;Department of Production Animal Sciences, Norwegian School of Veterinary Science, Oslo, Norway;;Department of Clinical Sciences, Division for Reproduction, Faculty of Veterinary Medicine and Animal Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden;;Department of Animal and Aquacultural Sciences, The Norwegian University of Life Sciences, Ås, Norway |
| |
| Abstract: | A field trial was performed in order to evaluate the effect on fertility of different straw types, freezing protocols (one- or two-step) and thawing procedures (35°C and 70°C) using frozen–thawed ram semen. A total of 791 Norwegian Crossbred ewes were artificially inseminated during natural oestrus with semen collected from nine mature and proven Norwegian Crossbred rams. A milk-based extender was used for dilution. The ewes were allocated into one of the following three groups based on the different straw types and thawing temperatures: medium straw (0.5 ml) thawed at 35°C for 20 s (Med35), medium straw thawed at 70°C for 8 s (Med70) and mini straw (0.25 ml) thawed at 35°C for 15 s (Mini35). The semen to be frozen in mini straws was re-concentrated by centrifugation. Sperm number in each insemination dose was approximately 200 × 106 spermatozoa. The fertility results as 25-day non-return rate (NRR)] for Med35, Med70 and Mini35 were 53.1%, 50.8% and 58.3%, respectively, and the lambing rates 49.8%, 46.8% and 53.8%, respectively. No significant main effects were seen for straw type/thawing temperature (p = 0.17), ram (p = 0.06) or age of the ewe (p = 0.18) on NRR or lambing rates (p = 0.19, p = 0.16 and p = 0.27, respectively). Both NRR and lambing rate differed significantly among farms (p < 0.0001). |
| |
| Keywords: | |
|
|
