Accuracy of live ultrasound measurements to evaluate the total tissue depth (GR), as well as fat and LM depths at different scanning sites, was studied in 96 purebred Suffolk and Dorset lambs of both sexes slaughtered between 36 and 54 kg of BW. Before slaughter, 7 real-time ultrasound measurements were taken on lambs: fat and LM depths between the 12th and 13th ribs (transverse) and between the 3rd and 4th lumbar vertebrae (transverse and longitudinal), and GR. After slaughter, the measurements equivalent to ultrasound measurements were taken on digitized images of the cuts on the left half carcass of each lamb. Ultrasound GR and fat depth measurements were closely correlated with the corresponding carcass measurements (0.76 < or = r < or = 0.81). Ultrasound GR measurement exhibited a large error of central tendency, but the level of error due to the disturbance (ED) was comparable with fat depth measurements (ED = 8.5%; residual SD = 2.24 mm; CV of residuals = 9.5%). Ultrasound fat depth measurements were more accurate between the 12th and 13th ribs (error due to regression = 1.20; ED = 0.82) than between the 3rd and 4th lumbar vertebrae (error due to regression = 5.58 and 5.4; ED = 1.10 and 0.93, transverse and longitudinal, respectively), mainly due to image interpretation errors in the lumbar region. Measurements of LM depth demonstrated low variability in the population under study (SD = 2.6 mm), and these ultrasound measurements showed low correlation with the corresponding carcass measurements (0.34 < or = r < or = 0.43). The results of this study demonstrated that ultrasound measurements were more accurate for evaluating fat depth and the GR measurements than for estimating LM depths. Ultrasound GR measurement is a promising measurement, especially where carcass grading systems are based on this carcass measurement.

. 2002. Glycerol addition and conservation of fresh and cryopreserved ram spermatozoa. Can. J. Anim. Sci. 82: 347-356. Fresh extended ram semen has a short fertile lifespan whereas acceptable fertility with cryopreserved semen is achieved only by laparoscopy, which limits widespread artificial insemination in sheep. Although glycerol is considered essential for freezing spermatozoa, it is often included in extenders for short-term storage at above-freezing temperatures. To test the hypothesis that glycerol reduces the function of fresh sperm, ram semen was divided into two aliquots and diluted with commercial extenders that were identical, except that one contained 7% glycerol (n = 6). In a second experiment, ram semen was prepared for cryopreservation by a one-step dilution with a 7% glycerol extender or gradually, with a two-step protocol, to test the hypothesis that the method and time of glycerol addition affects sperm quality after freezing and thawing (n = 7). For both experiments, semen was diluted in a synthetic oviductal fluid (SOF-m) and sperm quality was assessed by computerassisted motility, viability and chlortetracycline fluorescence (CTC) patterns (an indicator of capacitation status). The presence of glycerol did not affect the quality of fresh sperm (P > 0.27). For cryopreserved sperm, the method of glycerol addition also did not affect thawed sperm. However, a decrease in sperm motility and viability, and different distribution of CTC patterns occurred due to the duration of time in extender and in SOF-m (P ≤ 0.0002). Cryo-capacitation was also observed. In conclusion, the presence of glycerol in the extender did not reduce ram sperm quality during conservation of the semen at 5°C or when it was used to completely and rapidly dilute the semen before cooling for cryopreservation. La semence de bélier fraîche (conservée à 5°C) a une durée de vie limitée tandis que la semence cryoconservée ne donne des taux de fertilité acceptables que lorsque la laparoscopie est utilisée, ce qui limite l'expansion de l'insémination artificielle chez l'ovin. Même si le glycérol est essentiel à la congélation des spermatozoïdes, il est souvent inclus dans les diluants destinés à la conservation de courte durée à des températures au-dessus du point de congélation. Afin de tester l'hypothèse selon laquelle le glycérol réduit la fonction des spermatozoïdes frais, la semence de bélier a été divisée en deux aliquotes et diluée avec deux diluants commerciaux identiques, à l'exception du fait qu'un contenait 7% de glycérol (n = 6). Dans une seconde expérience, la semence de bélier était diluée en une seule étape avec un diluant contenant 7% de glycérol ou graduellement, en deux étapes afin de tester l'hypothèse selon laquelle la méthode et le temps d'addition du glycérol affectent la qualité spermatique lors de la congélation-décongélation (n = 7). Dans les deux expériences, la semence était diluée dans un fluide synthétique mimant l'oviducte de la brebis (SOF-m) et la qualité de la semence était évaluée selon la motilité...

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