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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Concentrations of folates in serum and milk were determined during the first two parities in 7 Suffolk, 12 Finnsheep, and 15 Romanov ewes at 0 (mating), 60, 110, and 140 d of gestation and 1, 7, 14, 21, and 50 d of lactation. The number of lambs born at first and second parturitions was 1.38 +/- .13 and 1.71 +/- .13 for Suffolk, 2.00 +/- .32 and 2.33 +/- .57 for Finnsheep, and 2.67 +/- .24 and 3.20 +/- .22 for Romanov, respectively, and the concentration of folates at d 0 was 1.17 +/- .21, 1.87 +/- .19, and 2.14 +/- .17 ng/mL, respectively. During gestation, serum concentrations of folates declined in the three breeds, more quickly in Romanov and Finnsheep (from d 0 to 60) than in Suffolk (from d 0 to 110). This decline was followed by an increase in serum concentrations of folates from d 110 to 140 of gestation in the three breeds; the largest increase was observed in Romanov (breed x quadratic effect of time, P = .001). During lactation, Romanov had higher serum concentrations of folates than Finnsheep, which in turn had a higher concentration than Suffolk (P = .001). Colostrum of Romanov had the highest concentration of folates (164.9 +/- 11.9 ng/mL), followed by that of Finnsheep (125.0 +/- 9.5 ng/mL) and Suffolk (98.2 +/- 13.3 ng/mL). On d 7 of lactation, concentration of folates was similar in milk of Romanov (97.1 +/- 5.6 ng/mL) and Finnsheep (94.9 +/- 4.0 ng/mL) and was higher than in Suffolk (72.4 +/- 3.7 ng/mL). From d 14, the concentration of milk folates was similar among breeds and decreased slowly to approximately 40 ng/mL at d 50 (breed x quadratic effect of time, P = .005). The changes in serum concentration of folates during gestation of ewes were similar to those observed in sows, suggesting that exogenous supply of folates may not be optimal in ewes during gestation and lactation.

Sixty Romanov x Dorset (RVDP) and sixty Romanov x Suffolk (RVSU) male lambs were used in a 2 x 5 factorial arrangement of treatments including two breed crosses and five diets to determine the effect of breed crosses on performance and to compare growth and carcass characteristics of lambs. Diets consisted of an all-silage diet, silage supplemented with 100 g of fish meal.animal-1.d-1, or silage supplemented daily with concentrate at either 200 g or 400 g per animal, or ad libitum intake. Lambs were fed from an initial weight of 23 kg to a slaughter weight of 45 kg. There was no interaction (P > .10) between diet and breed for any parameter measured. Silage DMI was decreased (P < .05) by supplementation, but total DMI was similar among diets. The ADG was increased by fish meal and concentrate supplementation, with higher (P < .05) ADG observed with ad libitum access to concentrate. Lambs that had ad libitum access to concentrate had an improved gain:feed and required less time to reach market weight but had more carcass fat than lambs fed other diets. Lambs fed only silage had a higher percentage of carcass with poorer muscling than others. The highest percentage of carcasses with excellent to good muscling, normal fat covering, and grades A1 and A2 was obtained with fish meal supplementation. Lambs from the RVSU-crossbreed had better ADG than RVDP lambs but carcass quality of RVDP lambs was better than that of RVSU lambs.(ABSTRACT TRUNCATED AT 250 WORDS)

Ewes from selected lines of sheep from each of two breeds, Finns (high ovulation rate, low ovulation rate and control lines with respective ovulation rates of 5.4, 2.7 and 3.3) and Merinos (T Merinos selected for increased ovulation rate and control Merinos with respective ovulation rates of 1.9 and 1.2) were used to examine how selection to alter ovulation rate had altered follicle development. Ovarian antral follicles were counted, measured, classified as nonatretic or atretic (more than five pyknotic bodies). The growth of ovulatory follicles in vivo, followed by repeated follicle ink marking, also was compared in the three lines of Finns. Regardless of breed, ewes selected for high ovulation rate had a similar number of antral follicles and a similar extent of atresia compared with their controls. Alterations induced by selection were located in the last stages of folliculogenesis. T Merinos exhibited a lower proportion of atretic follicles among follicles greater than 3 mm and a larger diameter of the largest healthy follicle when preovulatory follicles were excluded. High-line Finn ewes recruited more follicles, which produced smaller preovulatory follicles, each containing a smaller number of granulosa cells compared with either the low- or control-line ewes. Hence, physiological selection for high ovulation rate raised it by different methods in Merino than in Finn ewes.

The goal of this study was to evaluate the impact of winter rearing environment on the growth performance and meat quality of heavy lambs. Half of sixty-four Dorset lambs (32 males and 32 females) were raised in each of two different environments: warm and cold with average temperature of 10.9 ± 0.7 °C and -2.0 ± 5.2 °C, respectively. The lambs were slaughtered at live weights of 41-45 kg for females and 46-50 kg for males. Cold environment had no adverse effect on either growth performance or carcass quality. The rate of longissimus dorsi muscle deposition (P = 0.049) and its depth at slaughter (P = 0.027) were rather greater in lambs reared in the cold environment and a higher proportion of oxido-glycolytic fibres (P = 0.047) was also observed in this muscle. Rearing environment had only a minor effect on the organoleptic qualities, with the cold environment promoting juiciness of the meat (P = 0.043). Therefore, cold environment rearing such as used in this study represents an economic advantage for lamb producers by reducing the costs associated with the construction of insulated barns, while maintaining growth performance, as well as carcass and meat quality. Key words: Lamb, rearing environment, temperature, growth, carcass, meat quality

the World Wide Web at:The online version of this article, along with updated information and services, is located on www.asas.org at Bibliotheque De L'Univ. Laval Section Des Acquisitions on September 10, 2010. jas.fass.org Downloaded from ABSTRACT: The objective of this work was to evaluate the reproductive performance of ewes exposed to a photoperiodic regimen consisting of continuous alternating 4-mo periods of long days (LD: 16 h of light/d) and short days (SHD: 8 h of light/d) in an accelerated lambing program of 3 lambings in 2 yr. A total of 211 prolific Rideau Arcott ewes were assigned to the photoperiodic treatment, whereas 37 ewes were maintained under natural annual variation in day length (control group). Ewes under the photoperiod regimen were divided into 4 subgroups (A, B, C, D). All these groups of ewes were exposed to the same light regimen, but the LD and SHD light sequences were staggered by 2 mo to permit the evaluation of the effect of time and season of mating on performance of the ewes treated with the photoperiod. The control ewes were treated with intravaginal sponges in the out-of-season breeding periods (conventional approach). Each group of ewes was studied over 3 reproductive cycles. Two groups of rams exposed to alternating 2-mo sequences of LD and SHD were used for mating. The short mean interval between ram introduction and conception for the groups exposed to artificial photoperiod (9.4 d) confirmed the effectiveness of the treatment to induce intense sexual activity. For the 12 breeding periods studied (8 in outof-season and 4 in sexual season), fertility rate of the ewes treated with photoperiod, mated at various times of year, was 91.6%, which is comparable with the fertility normally seen in the natural breeding season. The number of lambs born/ewe remained constant across reproductive cycles and was greater in photoperiodtreated groups (2.81 vs. 2.27 for photoperiod and control groups, respectively; P = 0.0002). Groups exposed to photoperiod treatment obtained better fertility rate than the control group in out-of-season breeding (91.1 vs. 76.3%; P = 0.016). Ewes managed under the photoperiod regimen produced 1.38 lambings/yr and 69% of them lambed 3 times in 2 yr. Overall, the ewes in the photoperiodic treatment produced annually 3.78 lambs/ ewe. The reproductive performances achieved throughout the years indicate that the photoperiodic program tested, consisting of continuous alternating 4-mo periods of LD and SHD, allows control of the annual reproductive cycles in ewes.