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The control of reproduction in goats is interesting for technical reasons (synchronization of kiddings, adjustment to forage availability or to economy), and for genetic reasons (identification and dissemination of improved genotypes). The use of short-light rhythms leads to markedly increased production of semen per buck and prevents occurrence of a 'resting' season. Recent identification of a bulbourethral lipase in goat spermatozoa opens new perspectives in sperm preservation. Light plus 'short day' treatments also allow induction of out-of-season oestrous cycles and ovulations leading to enhanced fertility. Repeated use of eCG provokes the production of antibodies, delays the timing of ovulation and causes a reduction in fertility after fixed-time artificial insemination. All steps of embryo production, freezing and transfer are now controlled and allow the attainment of satisfactory numbers of kids born per donor female, which are compatible with the development of the technique for exchanging genotypes between countries. In vitro production of embryos allows high development rates to be achieved after in vitro maturation and fertilization of oocytes, and will ensure the production of synchronous populations of one-cell zygotes at the stage required by new biotechnologies.

Goats are spontaneously ovulating, polyoestrous animals. Oestrous cycles in goats are reviewed in this paper with a view to clarifying interactions between cyclical changes in tissues, hormones and behaviour. Reproduction in goats is described as seasonal; the onset and length of the breeding season is dependent on various factors such as latitude, climate, breed, physiological stage, presence of the male, breeding system and specifically photoperiod. In temperate regions, reproduction in goats is described as seasonal with breeding period in the fall and winter and important differences in seasonality between breeds and locations. In tropical regions, goats are considered continuous breeders; however, restricted food availability often causes prolonged anoestrous and anovulatory periods and reduced fertility and prolificacy. Different strategies of breeding management have been developed to meet the supply needs and expectations of consumers, since both meat and milk industries are subjected to growing demands for year-round production. Hormonal treatments, to synchronize oestrus and ovulation in combination with artificial insemination (AI) or natural mating, allow out-of-season breeding and the grouping of the kidding period. Photoperiodic treatments coupled with buck effect now allow hormone-free synchronization of ovulation but fertility results after AI are still behind those of hormonal treatments. The latter techniques are still under study and will help meeting the emerging social demand of reducing the use of hormones for the management of breeding systems.

International audience; The objective of this study was to evaluate genetic and non-genetic factors influencing characteristics of young buck semen production using a multivariate model that takes into account the longitudinal structure of data. Data were collected from 1989 to 2002 at two French A.I. centres. The data corresponded to 13151 and 9206 ejaculates of 758 Alpine and 535 Saanen bucks respectively, collected at the beginning of the first breeding season (September–December). The semen volume, the total number of spermatozoa, the concentration, the motility score of spermatozoa after freezing and the percentage of motile spermatozoa after freezing were registered for each ejaculate. Within-breed heritabilities and repeatabilities were estimated using a multivariate animal model using a power spatial covariance structure for environmental effect. For all characteristics and the two breeds, the main source of variation was the year–month interaction that interacted with the centre. We observed a decrease in years of motility score after freezing. Age and frequency of collection had a significant effect on semen volume and number of spermatozoa for both breeds, and on concentration of spermatozoa for the Alpine breed. No effect of these factors was found on the characteristics observed after freezing. Heritabilities for concentration, number of spermatozoa, semen volume, motility score after freezing and percentage of motile spermatozoa after freezing per ejaculate were respectively, 0.32, 0.15, 0.25, 0.12 and 0.05 for the Saanen breed and 0.34, 0.25, 0.29, 0.17 and 0.03 for the Alpine breed. Genetic correlations between volume and number of spermatozoa were respectively, 0.74 for the Alpine breed and 0.86 for the Saanen breed. Further study is required to compare the semen characteristics of young bucks with their mature production.

Remerciements : Plate-Forme Phénotypage Endocrinologie, INRA, UMR PRC, 37380 Nouzilly, Centre Val de Loire; Goat oestrous and ovulatory response to the ‘male effect’ was characterised to determine the time range over which fertile ovulations occur after buck exposure. The results were used to explore the efficacy of different hormone-free artificial insemination (AI) protocols aimed at diminishing the number of inseminations needed to optimise fertility. Adult bucks and does were exposed to artificially long days during winter, then exposed to a natural photoperiod before buck exposure (Day 0). Most goats (>70%) ovulated twice, developing a short cycle followed by a normal cycle over 13 days after buck exposure. Among them, 21% were in oestrus at the short cycle and 94% at the normal cycle. This second ovulation occurred within 48 h of Day 6 and was the target for AI protocols. In protocol A (n=79), goats were inseminated 12h after oestrus detection from Day 5 to Day 9. Up to six AI times over four days were needed to inseminate goats in oestrus. Forty-nine percent of the inseminated goats kidded. In protocol B (n=145), oestrus detection started on Day 5. The earlier (group 1) and later (group 2) buck-marked goats received one single insemination at fixed times on Days 6.5 or 7 and 8, respectively; unmarked goats (group 3) were inseminated along with group 2. In protocol C (n=153), goats were inseminated twice on Days 6.5 or 7 and 8 without needing to detect oestrus. Goats induced to ovulate by hormonal treatment were used as the control (n=319). Fertility was lower in protocol B than C and control (47 vs. 58 vs. 65% kidding; p≤0.05), whereas this was higher in buck-marked goats than unmarked ones (64 vs. 33%; p≤0.05). In protocol B, fertility can increase (>60%) when only goats coming into oestrus are inseminated. The best kidding rate (∼70%) was achieved when does were inseminated within 24h of the LH surge. Protocols involving insemination on Day 7 instead of Day 6.5 led to more goats being inseminated during this favourable time.

This article presented the results of “buck effect” in local Greek genotypes. These observations were made in an experimental station and in private flocks where sexual activity of males and females were determined. Testis volume increased two-fold from January to July. Intensity of sexual behaviour also rose in March when five of 14 bucks displayed sexual behaviour. All five bucks remained seasonally active throughout the experiment. The volume of their ejaculate increased from 0.8 to 1.2 ml, but the total counts of spermatozoa and the concentration decreased. Motility and viability remained high (4% and 70–80%, respectively) during the full experimentation period and did not show significant seasonal differences. Ovarian activity of some females continued up to March but all females were in ovarian inactivity throughout spring. Despite this 100% inactivity, all ovulated after buck introduction. This suggested that the breeding period could be advanced using “buck effect”, with males that where not at the maximum of their sexual activity.

The fertilization capacity of goat sperm stored in milk extenders is approximately 12-24h. Long-term storage of goat sperm (up to 3 days) is desirable as it would confer greater flexibility to breeding farms. The aim of this study was to evaluate in vitro motility parameters of buck spermatozoa for up to 7 days of storage using skim milk or chemically defined extender supplemented with native phosphocaseinate (NPPC). Four experiments were conducted to determine optimum temperature (4 or 15 degrees C) and storage conditions (aerobic versus anaerobic), the effect of seminal plasma on sperm survival, the optimal concentration of NPPC and the effect of beta lactoglobulin (BL). Both skim milk and NPPC were found to be more efficient for preserving goat sperm at 4 degrees C than at 15 degrees C (P

Chez les races caprines saisonnées, les méthodes d’amélioration de production et de conservation de semence doivent prendre en considération l’influence de l’environnement et en particulier de la photopériode. Par la fonction qu’elle exerce sur la régulation du développement gonadique, celle-ci contribue indirectement au contrôle du comportement sexuel et de la production de sperme, tant du point de vue quantitatif que qualitatif. L’utilisation de traitements photopériodiques constitue donc un outil efficace pour augmenter la production des doses de sperme destinées à l’insémination artificielle durant la carrière de reproducteur du bouc. Afin d’optimiser la production et la qualité de la semence, une sélection préalable des mâles est cependant nécessaire. Un problème spécifique dans la conservation de la semence de bouc est l’effet délétère du plasma séminal sur la viabilité des spermatozoïdes après congélation / décongélation, principalement lorsqu’ils sont dilués dans des milieux à base de lait ou de jaune d’œuf. La protéine responsable de cet effet est une enzyme sécrétée par les glandes bulbo-uréthrales appartenant à la famille des lipases pancréatiques et qui possède une double activité lipasique et phospholipasique. La conservation de la semence à l’état liquide, peu coûteuse, est un complément à la cryconservation pour développer l’insémination artificielle à grande échelle. Mais la diminution de la fécondance après 12 heures de conservation est un frein à l’utilisation de cette technique. Les méthodes de congélation disponibles actuellement diffèrent sur plusieurs aspects. Les plus efficaces incluent le lavage de la semence pour éliminer le plasma séminal dès la collecte.

The use of a simple cryopreservation method, adapted to direct transfer of thawed embryos may help to reduce the costs of embryo transfer in sheep and increase the use of this technique genetic improvement of this species. Two experiments were made to test a vitrification method that is easy to apply in field conditions. All embryos were collected at Day 7 of the estrous cycle of FSH-stimulated donor ewes and were assessed morphologically, washed in modified PBS and incubated for 5 min in 10% glycerol, for 5 min in 10% glycerol and 20% ethylene glycol and were transferred into the vitrification solution (25% glycerol and 25% ethylene glycol). All solutions were based on mPBS. Embryos were loaded in straws (1 cm central part, the remaining parts being filled with 0.8 M galactose in mPBS) and plunged into liquid N2 within 30 sec of contact with the vitrification solution. The straws were thawed (10 sec at 20°C) and the embryos were either transferred directly or after 5 min of incubation in the content of the straw (followed by washing in PBS) into the uterus of a recipient ewe. In Trial 1, the pregnancy rates at term (72 vs. 72%) as well as the embryo survival rates (60 vs 50% respectively) were not different between fresh (n = 48 embryos) and vitrified (n = 50) embryos. In a second trial no difference was observed between vitrified embryos transferred after in vitro removal of the cryoprotectant (n = 86 embryos) or directly after thawing (n = 72) both in terms of lambing rate (67 vs. 75%, respectively) and embryo survival rate (lambs born/embryos transferred; 49 vs. 53%). This method of sheep embryo cryopreservation provided high pregnancy and embryo survival, even after direct transfer of the embryos.

Nous avons étudié, au cours de quatre essais sur des chevrettes Alpine (n=158), les facteurs de variation de la réussite à l’insémination artificielle (IA) réalisée à un âge moyen de 8 mois. Après une mise en lot sur des critères zootechniques, les régimes expérimentaux ont été appliqués depuis 25 jours avant et jusqu’à 21 jours après l’IA. En moyenne, en régime Bas, les croissances des chevrettes ont été diminuées (- 22 g/j), alors qu’elles se sont maintenues (+ 54 g/j) lorsque les chevrettes étaient en régime Haut. L’évolution des métabolites plasmatiques juste après la mise en régime est conforme aux résultats de la bibliographie. En revanche, l’application des traitements hormonaux (pose des éponges vaginales 11 jours avant IA) provoque des évolutions qui ne sont plus conformes à l’état nutritionnel des animaux. Chez les chevrettes en alimentation restreinte, le pic pré-ovulatoire de LH apparaît en moyenne plus tôt que chez les chevrettes correctement alimentées (28,6 h vs 31,3 h ; P

In France, goat Artificial Insemination (AI) plays an important role in the milk intensive production system to control reproduction and, in conjunction with progeny testing, to improve milk production. About 60 000 goats were inseminated in 1996, 95% of them before the breeding season with deep frozen semen after induction of oestrus and ovulation by hormonal treatment. The efficiency of this method was about 65% of kidding rate. In 1996, 290 000 lactating goats were officially recorded. The selection scheme, aimed at improving protein yield and protein content, benefits from the sampling program for young AI buck. AI allows higher selection intensities for male selection, adequate genetic evaluations through genetically connected herds, and monitoring and selection of bucks for major genes like the αs1-casein gene. In order to further develop AI, a cooperative action between the partners of the dairy goat industry (Research, Agricultural extension and Farmer organizations) has operated since 1992 with the aim of reducing the variability of fertility rates. This program includes improvement of the control of reproduction by hormonal treatments, AI conditions, embryonic mortality and pseudopregnancy.

En France, l’insémination artificielle caprine (IA) joue un rôle important dans les systèmes intensifs de production laitière, pour la maîtrise de la reproduction et en relation avec le schéma national d’amélioration génétique de la production laitière. Environ 60 000 chèvres ont été inséminées en 1996, après induction hormonale de l’oestrus et de l’ovulation, avec de la semence conservée congelée. 95 % des IA ont été réalisées avant la saison sexuelle. L’efficacité de cette méthode de reproduction est d’environ 65 % de mise bas. En 1996, les résultats de 290 000 lactations de chèvres ont été enregistrés par le contrôle laitier officiel. Le principal objectif du schéma de sélection, qui inclut la sélection des meilleures boucs et chèvres comme parents des futurs boucs d’IA, concerne l’amélioration de la teneur en matières protéiques et le taux protéique du lait. L’IA permet une forte intensité de sélection des mâles, une évaluation génétique convenable à travers les élevages connectés génétiquement et la sélection des boucs porteurs de gènes majeurs comme celui de la caséine alpha S1. Depuis 1992, un Groupe National de Reproduction Caprine, incluant tous les partenaires de la filière caprine, est actuellement focalisé sur l’étude des facteurs de variations de la fertilité après IA afin de poursuivre le développement de cette technique.

Radioimmunoassay (RIA) was used to measure plasma eCG binding in dairy goats (n = 524) at the beginning of a progestagen/eCG treatment and 25 d after eCG administration. The eCG binding was not dependent on the age of the females but increased with the number of treatments they had previously received (3.4 % ± 4.8, n = 47 vs 9.6 % ± 13.2, n = 249; mean ± SD; P

Prediction of the future fertility of a given ejaculate with a simple laboratory test is still considered a real issue in domestic mammal breeding. This study showed that a subjective assessment of the percentage of motile spermatozoa, measured 120 min after thawing (mob120), can predict a significant part (~50%) of the variation of the future fertility of buck ejaculates. The predictive model was calculated using a calibration data set composed of 40 ejaculates from four Alpine and six Saanen bucks. A fertility trial using split ejaculates was conducted in order to estimate ejaculate fertility. Taken into account were the herd within breed factor and the year, month, and inseminator factors. On average, one ejaculate was used to inseminate two females per herd in 10 different herds. This calibration set allowed us to choose the mob120 variable among a set of laboratory tests: mitochondrial activity, acrosomal status, membrane integrity, osmotic resistance test assessed by flow cytometry, velocity and motion characteristics assessed by computer-assisted sperm analysis, visually assessed percentage of motile, and motility score measured 5 and 120 min after thawing. For the calibration step, the best model used the logarithm of mob120 and gave a correlation coefficient of 0.71 between the field fertility and the predicted fertility and a standard error of 0.17. We tested this model on 3 different validation data sets adding up to 95 ejaculates that were all different from those of the calibration data set. The correlation coefficients between field fertility and predicted fertility were always significant and the bias corrected standard error ranged from 0.15 to 0.18 on these validation data sets. A Monte Carlo simulation showed that about 20% of the fertility variation remained to be explained.

The control of reproduction is necessary to optimise the productivity of livestock production systems. The regulations of organic farming do not impose specific reproductive practices among those that are already in use except that some of them are not authorized. Whatever the animal species, the success of reproduction in organic systems mainly relies on the choice of adapted breeds. Because sheep and goats are well-known seasonal breeders the major issue is to overcome this limitation of reproductive possibilities. In these organic farming systems the reproduction is possible all year round thanks to the manipulation of daylight duration without using melatonin, however up to now these treatments are not developed. The male effect is another method to overcome seasonal blockade am that allows synchronizing lambing and kidding without any hormonal treatments. This method is however rather difficult to apply in all situations. Artificial insemination (AI) is the main way to benefit from selection's progress. In conventional systems At is performed a fixed time after hormonal synchronization of ovulations without necessity to detect oestrus. AI, which is authorized on natural oestrus, in not really used in organic flocks because they are spread over several days. Synchronization of oestrus with the male effect is however promising way to perform AI and allow organic breeders to benefit from selection schemes. In conventional swine production systems the classical practice is to drive sows into a 7 batches system at 3 weeks interval. The productive cycle duration is of 21 weeks including 28 days of suckling. In the European regulation of organic farming systems, the piglet suck ling period should not be shorter than 40 days. Practically the weaning will occur at 42 days with a 8 batches system. Hence the whole productive cycle of the sow will be lengthened up to 23 weeks. In organic system, like in conventional systems, weaning is the main method to synchronize sows oestrus within a given batch. The overall efficiency of organic production is however reduced because no hormonal treatment is allowed either to synchronize gilts or to transfer open sows into another band and those that may show oestrus during lactation. In all pig production systems AI is performed after oestrus detection. In cattle, AI is generally performed after detection of natural oestrus. Reproduction is mainly performed through AI in dairy cows ani with bull mating in beef cows. Thus the fact that hormonal treatments are not allowed in organic systems do not penalise them Furthermore reproduction is possible all year round except that it is performed according to productive goals and local constraints. The development of natural methods for the control of reproduction in organic livestock systems implies numerous research approache and multidisciplinary programs, often common to different species. INRA is strongly involved in the study of hormone-free methods ani their adaptation to breeding constraints., La maîtrise de la reproduction contribue à optimiser la productivité de l’exploitation. La réglementation de la production biologique n’impose pas de conduite de reproduction spécifique, mais limite les pratiques autorisées parmi l’ensemble des stratégies disponibles pour les éleveurs. Les conséquences de ces limitations sont plus ou moins pénalisantes selon l’espèce animale considérée. Ainsi, l’interdiction des traitements hormonaux représente le principal obstacle pour la maîtrise de la reproduction en agriculture biologique (AB) chez les petits ruminants et les porcins. La maîtrise de la saisonnalité de la reproduction est un objectif pour la plupart des éleveurs ovins et caprins. Dans ces deux espèces, la reproduction est possible tout au long de l’anoestrus saisonnier grâce à des traitements lumineux sans recours à la mélatonine, mais des difficultés de mise en œuvre font qu’ils sont aujourd’hui peu utilisés en AB. En élevage conventionnel ovin et caprin, l’insémination artificielle (IA) est réalisée à un moment fixe après synchronisation hormonale des ovulations et sans détection d’oestrus. En AB, l’IA est autorisée sur chaleurs naturelles : cela implique la pratique systématique de la détection des chaleurs sur plusieurs jours pour identifier les femelles à inséminer. Pour cette raison, l’IA est très peu pratiquée en AB chez ces deux espèces. La synchronisation des ovulations par effet mâle est une alternative prometteuse pour simplifier les protocoles d’IA, facilitant l’accès des éleveurs AB aux schémas de sélection et donc la généralisation de cette pratique. La conduite de reproduction la plus courante en élevage de porc conventionnel est dite en 7 bandes. La durée du cycle d’une bande est de 21 semaines dont 4 semaines d’allaitement. En AB, le règlement européen impose l’augmentation du temps d’allaitement des porcelets à 40 j minimum. En pratique, le sevrage a lieu à 42 j avec une conduite en 8 bandes, le cycle de reproduction s’étend donc à 23 semaines. En AB comme en conventionnel, le sevrage est la principale méthode utilisée pour la synchronisation de l’oestrus des truies dans leur bande. L’efficacité de la conduite en bandes est toutefois pénalisée en AB par l’interdiction des traitements hormonaux, utilisés fréquemment en conventionnel pour intégrer les cochettes dans les bandes, pour recycler des femelles décalées ou pour prévenir des oestrus de lactation. Cependant, l’interdiction de l’utilisation d’hormones ne pénalise pas la pratique de l’IA car elle est réalisée sur oestrus naturels synchronisés par le sevrage chez la majorité des producteurs en AB et en élevage conventionnel. Chez les bovins, l’insémination est pratiquée de manière générale sur chaleurs naturelles. Lors de la mise à la reproduction, la mise en place de la semence est réalisée par insémination artificielle (majoritaire en élevage laitier) ou par monte naturelle (majoritaire en élevage allaitant). L’interdiction des traitements hormonaux d’induction et de synchronisation des chaleurs n’est donc pas pénalisante en AB par rapport à l’élevage conventionnel. La mise à la reproduction est possible toute l’année, avec des contraintes qui diffèrent selon les objectifs de production. Les voies de recherche pour le développement de méthodes naturelles de maîtrise de la reproduction utilisables en AB sont très diverses, multidisciplinaires et souvent communes aux différentes espèces de mammifères d’élevage. L’INRA contribue fortement à l’amélioration des méthodes existantes et à leur adaptation aux contraintes d’élevage. Il s’implique également dans la conception et la validation de nouvelles approches de maîtrise de la reproduction sans hormones. Ce développement ne pourra connaître un véritable essor que dans le cadre d’une relation étroite entre la recherche finalisée et les professionnels.

Bucks show seasonal variation in their body weight and sexual activity. Three groups of six Alpine and Saanen bucks were used over two consecutive years to investigate if rapid alternations between long and short days could abolish this seasonal variation. The control group was kept under natural annual daylength, while the experimental groups were exposed to alternations of either 1 month of 16L:8D and 1 month of 8L:16D (2-month treatment) or to 2 months of 16L:8D and 2 months of 8L:16D (4-month treatment). In the control group, body weight, sexual behavior, testicular weight and sperm production showed important seasonal variations: body weight decreased between September and January by about 7 kg; refusal to ejaculate went up to 25% in August; testicular weight varied from 103 +/- 2 g (March) to 149 +/- 7 g (October). In contrast, seasonal variations of these parameters decreased in the two experimental groups. In the 2-month treatment group, testicular weight increased from 134 +/- 7 (March) to 148 +/- 8 g (October); while in the 4-month treatment group it increased from 123 +/- 10 to 138 +/- 12 g, respectively; in the same period, the two experimental groups of bucks produced a larger total number of spermatozoa per ejaculate (6.3 +/- 0.3 x 10(9); 2-month treatment and 7.2 +/- 0.3; 4-month treatment) than in the control group (4.2 +/- 0.4). We conclude that rapid alternations between long and short days decreased seasonality in the sexual activity of bucks.

Reproductive seasonality observed in all breeds of goats originating from temperate latitudes and in some breeds from subtropical latitudes can now be controlled by artificial changes in photoperiod. Short days stimulate sexual activity, while long days inhibit it. This knowledge has allowed the development of photoperiodic treatments to control sexual activity in goats, for both the buck and doe. In the French intensive milk production system, goat AI plays an important role to control reproduction and, in conjunction with progeny testing, to improve milk production. Most dairy goats are inseminated out of the breeding season with deep frozen semen, after induction of oestrus and ovulation by hormonal treatments. This protocol provides a kidding rate of approximately 65%. New breeding strategies have been developed, based on the buck effect associated with AI, to reduce the use of hormones. With the development of insemination with frozen semen, a classical selection programme was set up, including planned mating, progeny testing and the diffusion of proved sires by inseminations in herds. Functional traits have become important for efficient breeding schemes in the dairy goat industries. Based on knowledge gained over the past decade, the emphasis in selective breeding has been placed on functional traits related to udder morphology and health. New windows have been opened based on new molecular tools, allowing the detection and mapping of genes of economic importance.

International audience; The aim of this study was to demonstrate that embryo transfer can be used to produce CAEV-free kids from CAEV-infected biological mothers when appropriate procedure is implemented. Twenty-eight goats that had tested positive for CAEV using PCR on vaginal secretions were used as embryo donors. Embryos with intact-ZP were selected and washed 10 times; they were then frozen and used for transfer into CAEV-free recipient goats. Nineteen of the 49 recipient goats gave birth, producing a total of 23 kids. Three blood samples were taken from each recipient goat, 10 days before, during, and 10 days after parturition; these were tested for CAEV antibodies using ELISA and for CAEV proviral DNA using PCR. The mothers were then euthanized. Tissue samples were taken from the lungs, udder, and retromammary and prescapular lymph nodes. The kids were separated from their mothers at birth. Seven of them died. At 4 months of age, 16 kids were subjected to drug-induced immunosuppression. Blood samples were taken every month from birth to 4 months of age; samples were then taken on days 15, 21, and 28 after the start of the immunosuppressive treatment. The kids were then euthanized and tissue samples taken from the carpal synovial membrane, lung tissue, prescapular lymph nodes, inguinal and retromammary lymph nodes, and uterus. All samples from the 19 recipient goats and 23 kids were found to be negative for CAEV antibodies and/or CAEV proviral DNA. Under acute conditions for infection this study clearly demonstrates that embryo transfer can be safely used to produce CAEV-free neonates from infected CAEV donors.

International audience; The response to the male effect was studied in two Saanen and two Alpine flocks over 5 consecutive years. Adult male and female goats were exposed to artificial long days (16 h light and 8h darkness, 16L:8D)in open barns for approximately 3 months (between December 1 and April 15) followed by a natural photoperiod. Goats were treated for 11 days with fluorogestone acetate (FGA) or progesterone (CIDR) immediately before joining. Bucks carrying marking harnesses with adapted aprons joined females 49-63 days after the end of the long-day treatment (between April 30 and June 5) and were left with them for 5 days. In experiment 1 (n = 142), FGA- and CIDR-treated goats were inseminated at a time based on the detection of oestrus. Two insemination groups were distinguished by the occurrence of marking over a 48-h period. Earlier (group 1) and later (group 2) buck-marked goats received one single insemination 12-24 In or 0-12 h after marking, respectively. Unmarked goats were inseminated along with group 2. In experiment 2 (it = 344), FGA-treated goats were inseminated 52 and 70 h (52 h:70 h group) or 52 and 75 h (52 h:75 h group) after joining. In experiment 3 (n = 285), FGA-treated goats were inseminated 52 h (1-AI group) or 52 and 75 h(2-AI g-roup) after joining. In all experiments, an external control group given the "classical" insemination program was analysed. Over the 5-year period, 92% of the goats exhibited an LH surge during days 1-4 after joining and 98% of them ovulated. Eighty-seven percent of the LH surges detected in milk occurred during the 33-57 h interval after joining, indicating that ovulation took place around 45-69 h. In experiment 1, 96% of the goats were marked 22-70 h after joining. Kidding rate (KR; 78%) was similar between insemination groups and between FGA- and CIDR-treated goats (p > 0.05). Most of the goats (95%) were inseminated during the interval between 15 h before and up to 4 h after ovulation. KR was not affected by the time between detection of marking and insemination or between insemination and ovulation (p > 0.05). In experiment 2, KR (75%) was similar in both insemination groups (P > 0.05). In experiment 3, KR was higher (p < 0.05) in the 1-AI (71%) than the 2-AI group (57%). In all experiments, KR of the control group (68-73%) was similar to that achieved in goats induced to ovulate by the male effect. Prolificity (2.1 +/- 0.7) was not affected by any of the factors examined (p > 0.05). In conclusion, high fertility can be achieved during anoestrus when 1 or 2 inseminations are performed over a 24 h period, determined by oestrus or by the introduction of the buck, if light-treated goats receive 11-day FGA or CIDR treatment and are then induced to ovulate by the male effect. (C) 2007 Elsevier B.V. All rights reserved.

absent

International audience; Standard artificial insemination (AI) using a speculum in dairy goats does not result in acceptable fertility rates in nulliparous does. An explanation might be the difficulties to pass the cervical canal in nulliparous females with the insemination gun, increasing the time needed for semen deposition. Nulliparous Alpine dairy goats were used to evaluate whether time interval from insertion to withdrawal of the speculum is a factor influencing pregnancy rates to first AI with frozenthawed semen. Oestrus was synchronized using fluorogestone acetate intravaginal sponges (FGA, 40 mg) for 11 days, associated with 50 mg i.m. of cloprostenol and 250 IU i.m. eCG 48 ± 2 h before sponge removal. In the first experiment (n = 52; 3 herds), the average duration of the AI procedure was 42 ± 10 s, with a median of 39 s. AI performed in less than 39 s resulted in higher pregnancy rates (75%, n = 28) than AI lasting for more than 39 s (46%, n = 24). In the second experiment, does (n = 325; 5 herds) were randomly assigned into two treatment groups according to a short (20 s) or long (60 s) AI procedure. We showed that the duration of AI affected fertility after a first insemination, and that pregnancy rate was significantly improved using a short-duration AI (61.2%; n = 169) compared with a long-duration AI (44.2%; n = 156). We have previously shown in the ewe that genital stimulation during AI enhanced uterine motility. Other authors reported a negative correlation between increased uterine motility at the time of AI and fertility rates in small ruminants. The results of this study suggest that rapid semen deposition may limit the reflex activation of uterine contractions provoked by the speculum and the movement of the insemination gun, and thus ameliorates reproductive performance to first AI in nulliparous goats.

The response to the male effect was studied in two flocks of Saanen and three of Alpine goats during deep anoestrus in three consecutive years. Males and females were subjected to artificially long days for about 3 months (between December 4 and April 1) followed by a natural photoperiod. Bucks joined goats 42-63 days after the end of the long days treatment (between April 20 and June 3) and fertilisation was ensured by natural mating. In experiment 1 (n=248), female goats were treated or untreated with melatonin at the end of the long days treatment and treated or untreated for 11 days with fluorogestone acetate (FGA) before teasing. The males received melatonin implants. In experiment 2 (n=337), the factor studied was the association or non-association of the 11-day FGA treatment. Neither males nor females received melatonin implants. In experiment 3 (n=180), goats were treated for 11 days with FGA or with natural progesterone (CIDR). Neither males nor females received melatonin implants. In experiment 1, among the non-cycling goats (n=218), 99% ovulated and 81% kidded at 161+/-8 days after joining. Ninety-two percent of FGA-treated goats displayed an LH surge at 65+/-11h after teasing. Melatonin treatment did not affect any parameter but FGA advanced the kidding date. In experiment 2, 94% of the goats ovulated and 87% kidded. A major peak of conception was observed on days 3 and 8 after joining in FGA-treated and untreated goats, respectively. Among the FGA-treated goats, 83% displayed an LH surge. Over all flocks, most of the LH surges occurred over a 24-36 h interval, but the surge was initiated at different times in different flocks (36, 48 or 60 h after joining). FGA treatment did not influence the results, except for advancement of births of about 5 days. Differences among flocks were highly significant. In experiment 3, 94% of the goats displayed the LH surge, 93% ovulated and 68% kidded. Significant differences were found among flocks, but not between the FGA and CIDR groups. Bucks marked 85% of the goats 24-72 h after joining. The time interval between the detection of marked goats and detection of the LH surge depended on the time of marking (r=-0.62; p

Hypoosmotic swelling test (HOS) has been proposed by many authors to evaluate the functional integrity of the sperm membrane. Our approach in this experiment has consisted in exposing spermatozoa to a wide range of osmotic pressures then evaluating the reacted sperm cells by flow cytometry and finally modelling the sperm cell responses. Semen samples were diluted in skim milk or NPPC (native phosphocaseinate) extenders, and stored at 4 °C for 3 days. At D0 and D3 aliquots from each ejaculate (n = 12) were submitted to seven hypoosmotic solutions varying from 230 to 10 mOsm/kg. Sperm samples were analyzed using flow cytometry to determine two populations of spermatozoa identified by propidium iodide (PI): PI+ (including PI, red fluorescence) and PI− (excluding PI, no fluorescence). Spermatozoa PI+ were considered as spermatozoa with membrane damages. PI+ exhibited a high variation from 230 to 10 mOsm/kg which was considered as a dose–response curve. Data were modelled using Mixed procedure and probit analysis to a sigmoid curve. Each model curve characterized the profile of response of the variable PI+ to the range of osmotic pressure from 230 to 10 mOsm/kg. The estimated parameters modelling the sigmoid curves are discussed in order to evaluate the effect of extender (skim milk versus NPPC) and duration of preservation (D0 versus D3). Such modelling could help to differentiate storage method ejaculates within males or between male, contributing therefore to improve semen technology.

The storage of frozen semen for artificial insemination is usually performed in the presence of egg yolk or skimmed milk as protective agents. In goats, the use of skimmed milk extenders requires, however, that most of the seminal plasma is removed before dilution of spermatozoa because it is deleterious for their survival. It has been previously demonstrated that a lipase (BUSgp60) secreted by the accessory bulbourethral gland was responsible for the cellular death of goat spermatozoa, through the lipolysis of residual milk lipids and the release of toxic free fatty acids. This lipase was purified from the whole seminal plasma of goat and was found to display both lipase and phospholipase A activities, this latter activity representing the main phospholipase activity detected in goat seminal plasma. Based on its N-terminal amino acid sequence, identical to that of BUSgP60 purified from bulbourethral gland secretion, and the design of degenerated oligonucleotides, the lipase was cloned from total mRNA isolated from bulbourethral gland. DNA sequencing confirmed it was the goat pancreatic-lipase-related protein 2 (GoPLRP2). The physiological role of GoPLRP2 is still unknown but this enzyme might be associated with the reproductive activity of goats. A significant increase in lipase secretion was observed every year in August and the level of lipase activity in the semen remained high till December, i.e., during the breeding season. A parallel increase in the plasmatic levels of testosterone suggested that GoPLRP2 expression might be regulated by sexual hormones. The lipase activity level measured in goat seminal plasma, which could reach 1000 U/ml during the breeding season, was one of the highest lipase activity measured in natural sources, including gastric and pancreatic juices.

In small ruminants, progestagen-impregnated vaginal devices (sponges) are useful tools to manage reproduction irrespective of season and to the application of timed artificial insemination (AI). A novel progestagen releasing vaginal-controlled release device (Chronogest CR), loaded with less (20mg) cronolone using proprietary procedures, was developed and its efficacy (synchronising ability, fertility and prolificacy following sponge removal) evaluated versus the existing Chronogest sponge containing 45 mg of cronolone in goats. Females (n=199) were maintained in field conditions and inseminated with graded amounts of spermatozoa at two stages of the year (breeding and non-breeding seasons). The use of the new Chronogest CR sponge was associated with an earlier initiation of the LH surge (28.7h versus 30.8h following sponge removal, P

Ninety-eight Alpine goats of two herds were followed over 4 years in a program of annual artificial insemination after estrus induction/synchronization, including progestagen administration (vaginal sponge) followed by prostaglandin analog and equine chorionic gonadotrophin (eCG) 48 h before sponge removal. Goats were sampled every 4 hours from the 16th to the 56th following sponge removal, for determination of LH surge and tested for estrus by the presence of a buck. Seven days after AI, endoscopic examination of the ovaries was performed to determine the number of corpus lutea. Pregnancy diagnosis was performed at day 21-22 post AI by determination of plasma progesterone and at day 40-45 by ultrasonography. Parturition, number and sex of kids were recorded. All the goats were sampled before and after each treatment, for anti-eCG antibodies screening. Statistical analysis of the results clearly established a significant effect of the treatments on anti-eCG antibodies. Time of estrus and LH surge were significantly different between herd. The antibodies significantly delayed the time of coming out of estrus as well as the time of LH surge. Two antagonistic effects were evidenced: first, the delayed of time of estrus and time of LH surge in relation with the immune reaction to eCG; secondly, the ahead of time of estrus and time of LH surge during the years of treatment, identical to both herd. The antibodies negatively influenced the percentage of ovulating females as well as kidding rate. Finally, no effect of antibodies on prolificacy was found.

Sperm cryopreservation is used for preservation and diffusion of genetic diversity and genetic progress. One approach to improve cryopreservation is to identify and control the cellular parameters responsible for intrinsic sperm fitness for cryopreservation. The aim of this study was to determine if a relationship exists between sperm cholesterol/phospholipid molar ratio (CHO/PL) and sperm fitness for cryopreservation. CHO/PL in goat and boar semen were respectively 0.281 ± 0.048 (n = 112) and 0.375 ± 0.043 (n = 47). CHO/PL of washed stallion spermatozoa was 0.541 ± 0.072 (n = 17). In stallion spermatozoa and goat semen, CHO/PL and sperm motility after thawing were negatively correlated, although the significance of this relation fluctuated between ejaculates (stallion) and between months of collection (goat). In boar, mobility parameters after thawing were not related to CHO/PL, but a positive correlation was noted between CHO/PL and the percentage of spermatozoa alive and normal 120 min after thawing. No relationship was found between blood plasma cholesterol (goat: 1160 nmol.mL(−1) ± 186; boar: 1410 nmol.mL(−1) ± 200) or seminal plasma cholesterol (boar sperm rich fraction: 104 nmol.mL(−1) ±52) and sperm CHO/PL. To conclude, sperm CHO/PL is not a direct indicator of sperm fitness for cryopreservation. However, as supported by the observed correlation, it could not be ruled out that CHO/PL is involved in the cryopreservation success.

Environmental influences on reproduction and semen production in the buck, the problem of interaction between seminal plasma and egg yolk or milk constituents in diluent, liquid storage and processing of semen for freezing are discussed. A review is given on the use of frozen-thawed semen for artificial insemination (AI) in spontaneous and induced oestrus and factors influencing the fertility.

Le contrôle de la reproduction caprine est intéressant pour des raisons techniques (synchronisation des mise bas, ajustements aux disponibilités fourragères ou aux contraintes économiques), et pour des raisons génétiques (identification et dissémination des génotypes améliorateurs). L’utilisation de rythmes photopériodiques accélérés conduit à une augmentation très importante des doses produites pour l’insémination artificielle (IA) et évite l’apparition d’une contre-saison sexuelle. L’identification récente d’une lipase bulbo-uréthrale dans le sperme de bouc offre de nouvelles perspectives pour la conservation de la semence. Chez la chèvre, les traitements " lumière + jours courts " permettent également l’induction de cycles oestriens et ovulatoires à contre-saison, ce qui conduit à une amélioration de la fertilité des troupeaux. En revanche, l’utilisation répétée de eCG (autrefois appelée PMSG) provoque l’apparition d’anticorps, retarde le moment de l’ovulation et induit une baisse de fertilité après IA, lorsqu’elle est réalisée après un délai fixe après la fin du traitement. Toutes les étapes de la production d’embryons, de leur congélation et de leur transfert sont maintenant maîtrisées et permettent d’atteindre des taux satisfaisants de chevreaux nés par femelle donneuse, qui sont compatibles avec le développement de la technique dans le but d’échanger du matériel génétique entre les pays. La production in vitro d’embryons permet des taux élevés de développement après maturation et fécondation in vitro des ovocytes et pourrait permettre l’obtention de populations synchrones de zygotes au stade unicellulaire, nécessaire à l’application des biotechnologies., The control of goat reproduction is interesting for technical reasons (synchronisation of kidding, adaptation to forage availability or to economy), and for genetic reasons (identification and dissemination of improved genotypes). The use of short-light rhythms leads to dramatically increased production of AI doses per buck and prevents the occurrence of a "resting" season. Recent identification of a bulbo-urethral Lipase In goat sperm opens new perspectives in sperm preservation. Light+"short days" treatments also allow the induction of out-of-season estrous cycles and ovulations leading to enhanced fertility. Repeated use of eCG provokes the production of antibodies, delays the timing of ovulation and causes a reduction in fertility after fixed-time artificial insemination. All steps of embryo production, freezing and transfer are now controlled and allow the attainment of satisfactory rates of kids born per donor female, which are compatible with the development of the technique for exchanging genotypes between countries. In vitro production of embryos allows high development rates to be achieved after in vitro maturation and fertilisation of oocytes, and will ensure the production of synchronous populations of one-cell zygotes at the stage required by new biotechnologies.

La mélatonine est une substance naturellement sécrétée par la glande pinéale pendant la période obscure du nycthémère, qui transmet l’information photopériodique chez les mammifères. L’administration continue par un implant sous-cutané, comme dans les expérimentations décrites ici, permet de mimer les jours courts alors que les yeux des animaux perçoivent les jours longs naturels du printemps et de l’été. Il est nécessaire de faire subir une alternance de jours longs et de jours courts pour pouvoir maîtriser la période d’activité sexuelle. Chez la brebis conduite en lutte naturelle, un implant sous-cutané de mélatonine (Mélovine®) est inséré de 30 à 40 jours avant l’introduction des béliers. Les différents essais réalisés depuis plusieurs années chez 5 races françaises, et qui mettaient en comparaison, dans les mêmes élevages, des femelles traitées et des femelles témoins, montrent que la fécondité des brebis traitées est très supérieure à celle des brebis témoins (16 agneaux nés en plus pour 100 brebis mises en lutte). Les dates moyennes de mise bas sont plus précoces et moins étalées chez les traitées que chez les témoins. Chez la brebis également, cette fois-ci en association avec un traitement hormonal de synchronisation de l’oestrus et une insémination artificielle, la fécondité des brebis traitées, pour l’ensemble oestrus induit plus retours, est aussi très significativement supérieure à celle des brebis témoins (30 agneaux nés en plus pour 100 brebis mises à la reproduction). Chez la chèvre, du fait de la forte demande existante pour une lutte en pleine contre-saison (avril à juillet), il est recommandé de faire subir un traitement lumineux (éclairement supplémentaire avec aube fixe et "flash" nocturne) pendant une période d’au moins 2 mois avant la pose de l’implant de mélatonine. Les boucs recoivent le même traitement ; les femelles sont séparées de tout contact avec les mâles à partir de la pose de l’implant. La lutte naturelle se fait en introduisant les boucs traités parmi les femelles, de 35 à 70 jours après la pose de l’implant, de façon à bénéficier de "l’effet bouc". Dans ces conditions, la fertilité est voisine de celle observée en lutte naturelle pendant la saison sexuelle (supérieure à 80 %) et les fécondations ont lieu environ 10 jours après l’introduction des mâles. La prolificité est équivalente à celle observée en saison sexuelle. L’association de ce traitement avec un traitement progestatif classique de synchronisation hormonale des oestrus et avec l’insémination artificielle est en cours d’essai. Chez le bélier, l’insertion d’implants permet une avance de la croissance testiculaire et une amélioration de la production spermatique. Si l’on souhaite obtenir une activité spermatogénétique intense en pleine contre-saison, comme chez les mâles des centres d’IA, il est nécessaire de faire précéder la pose de l’implant d’une période de jours longs réels ou mimés par une heure d’éclairement nocturne. Un tel traitement stimule la croissance testiculaire, améliore le comportement sexuel, la production spermatique et augmente la fertilité après IA, par rapport aux béliers non traités. Il est également possible de faire subir aux béliers reproducteurs une alternance d’un mois de jours longs et d’un mois de jours courts, ce qui induit le maintien d’une activité spermatogénétique élevée et constante pendant plusieurs années. En bâtiment ouvert, sur des mâles laissés en photopériode naturelle, l’alternance d’un mois d’éclairement nocturne avec un mois d’implant de mélatonine permet d’aboutir aux mêmes résultats, la dépose de l’implant en fin de traitement devenant toutefois délicate. Chez le bouc, le même type d’alternance rapide entre jours longs et jours courts permet de maintenir une production spermatique élevée de bonne qualité pendant au moins trois années consécutives. Dans ces conditions, le nombre de doses de semence congelée produites est très supérieur chez les animaux traités par rapport aux animaux témoins (+41 à +69 %). La fertilité des chèvres inséminées artificiellement avec de telles doses n’est pas différente de celle des chèvres inséminées avec la semence des boucs témoins. Les implants de mélatonine Mélovine®, ont obtenu en 1995 l’autorisation de mise sur le marché., Melatonin is a natural compound naturally secreted by the pineal gland during the dark phase of the light/dark cycle, which transduces the photoperiodic information in mammals. The continuous administration of melatonin via a subcutaneous implant, as described here, allows to mimic short days while animal’s eyes perceive long days of spring and summer. It is necessary to impose an alternation between long and short days in order to control the period of sexual activity. In ewes under natural mating, a subcutaneous implant of melatonin (Melovine®) is inserted from 30 to 40 days before joining. The various experiments realised since some years in 5 French sheep breeds, and which compared in the same flocks treated and control ewes, have shown that fecundity of treated ewes is much higher than that of control ewes (16 lambs more per 100 ewes joined). Dates of lambing are more precocious and less spread in treated than in control ewes. Always in the ewe, in association with "classical" hormonal treatments for the control of oestrus and artificial insemination, melatonin treatment allows to significantly increase fecundity for the total induced oestrus and returns (30 lambs born more compared to control ewes). In the dairy goat, due to the strong demand existing for an out-of-season breeding (from April to July), it is recommended to impose a photoperiodic treatment (extra light with a fixed dawn and a nocturnal lighting) during more than 2 months before implant insertion. Natural mating is done by introducing treated bucks among the female goats, from 35 to 70 days after the end of the photoperiodic treatment, in order to use the "buck effect". Under these conditions, fertility is close to that normally observed during the annual breeding season (higher than 80 %) and fertilisations occur about 10 days after introduction of bucks. Litter size is close to that of the normal breeding season. The association with "classical" hormonal treatments and AI is on test. In the ram, insertion of melatonin implants allows an advance of testicular growth and an improvement of sperm production. If a full out-of-season sperm production is wished, as in AI centres, it is necessary previously to the insertion of implants to impose a light treatment composed of real long days or long days mimicked by one hour of extra light during the photosensitive phase. Such a treatment stimulates testicular growth, improves sexual behaviour, sperm production and increases fertility after AI, when compared to control rams. It is also possible to impose an alternation of one month of long days and one month of short days, which induces the maintenance of an elevated and constantly high sperm production during consecutive years. In open barns, in males left under natural lighting, the alternation of one month of extra light during the night with one month of melatonin treatment allows to reach the same results, removal of implants at the end of treatment remaining, however, difficult. In the buck, the same type of rapid alternation between long days and short days allows to maintain high sperm production of good quality during more than 3 consecutive years. Under such conditions, the number of deep-frozen sperm doses is much higher than that of control bucks (from 41 to 69 % more). Fertility of artificially inseminated goats is not different from that of goats inseminated with semen of control bucks. Melatonin implants Melovine® had obtained in 1995, the official registration in France.

In goats treated to induce superovulation, insemination at a predetermined time after the end of progestagen treatment leads to a low fertilization rate. To solve this problem we developed a new treatment based on the control of the occurrence of the endogenous LH peak with a GnRH antagonist (Antarelix®). The first experiment was designed to determine the dose of LH required to mimic a spontaneous LH preovulatory discharge; the injection of 3 mg, i.v. of pLH induced a peak of the same amplitude and duration as the spontaneous peak. Subsequently, in the second experiment, we compared 2 doses of Antarelix® (0.5 and 1 mg, sc) administered 12 h after sponge removal (9 goats/treatment group). The dose of 0.5 mg was selected for further experiments because it was effective in the inhibition of the endogenous LH peak and had no detrimental effect on the quality of embryos. In the final experiment, 48 goats received the new treatment and were inseminated (intrauterine) only once 16 h after LH injection; 41 were flushed and produced 5.3 ± 4.5 (m ± SD) transferable embryos. The developmental stage and the number of cells/embryo were within the range that has been reported for embryos produced with conventional treatments. In conclusion, with the described method, it is possible to inseminate goats at a predetermined time without decreasing the number of transferable embryos. This technique will encourage the development of embryo transfer within genetic programs, and it will be a valuable tool for the production of zygotes for gene transfer.

The aim of the present study was to compare the survival rates of goat morulae and blastocysts after different freezing procedures. The viability of frozen-thawed embryos was assessed both in vivo and in vitro. Two cryoprotectants, ethylene glycol and glycerol, were used and three cryoprotectant removal procedures were compared: progressive dilution in 1.0, 0.5, 0.3 and 0 M of cryoprotectant in PBS; a similar progressive dilution with cryoprotectant in PBS plus 0.25 M of sucrose; or one-step transfer in PBS containing 0.25 M of sucrose. In vitro development of frozen-thawed blastocysts was always higher than that of frozen morulae irrespective of the cryoprotectant (52 129 = 40.3% vs 23 161 = 14.3% ; P0.001). In vivo, however, frozen-thawed morulae developed equally as well as blastocysts after an identical freezing-thawing protocol. Development both in vivo and in vitro showed ethylene glycol to be a better cryoprotectant than glycerol for goat embryos at both developmental stages (23 vs 0%, 45 vs 35% in vitro; 34.5 vs 21%, 35 vs 23% in vivo for morulae and blastocysts, respectively).

The fertility rate for goats following artificial insemination (AI) is usually analyzed according to herd or treatment groups. However, these general information are insufficient to allow identification of specific factors which affect this individual reproductive performance. In the present experiment 640 dairy goats were used to analyze to what extent the interval from sponge removal to estrus affects the results of AI, performed at a predetermined time following sponge removal. Estrus occurred in 98.1% of experimental animals between 24 and 72 hours after sponge removal. The fertility rate was lower for goats that came into estrus later than 30 hours after sponge removal (33.3%, n = 108 than for goats that exhibited estrus earlier (65.0%, n = 520; P

Goat bucks show large seasonal variations in semen quality mainly influenced by photoperiodic changes. Minimum percentage of motile sperm cells and velocity occur during spring and summer. Three groups of Alpine and Saanen bucks (n = 6 in each group) were used to determine whether rapid alternations between long and short days were able to abolish seasonal variations in semen quality. One group remained in open sheds under natural day length (An) which varied from 16 h light (June) to 8 h light per day (December). The first experimental group (2Mo) was exposed to alternations between 1 month of long days (16L:8D) and 1 month of short days (8L:16D) and the second one (4Mo) to alternations between 2 months of long days (16L:8D) and 2 months of short days (8L:16D), during two consecutive years. All parameters of semen quality before freezing and after thawing varied with time in the three groups (P < 0.05). Interaction between group and time was also detected for five parameters out of six (P < 0.001), indicating that groups varied differently with time. Semen quality in the experimental groups was not affected by prevailing day length. As expected, in group An, the percentage of motile sperm and sperm motility score (0–5) before freezing and after thawing decreased during the nonbreeding season (March to August; minimum in August: 37.8% and 2.4 score before freezing) compared to the breeding season (September to February; maximum in January: 66.3% and 3.6 score before freezing). The production of semen doses available for A.I. also decreased during this period. In contrast, in the two experimental groups the decrease in sperm quality during this period was prevented. In these groups, the percentage of motile sperm and sperm motility before freezing and after thawing remained at the same level as observed in group An during the natural breeding season. Abolition of seasonal variation in semen quality led to production of 69.0 and 54.7% more A.I. doses in groups 2Mo and 4Mo than in group Am. Sperm fertility in the three groups did not show significant differences (59.4% of kiddings in 1599 goats from 58 flocks). It was concluded that, in goat bucks, alternations between long and short days abolished the seasonal variation in semen quality without altering sperm fertility.

SummaryCartilage slices obtained from weanling rachitic rats oxidize glucose carbon-1 to CO2 more rapidly than carbon-6. Insulin increases oxidation of both carbons where-as growth hormone has no effect. Growth hormone significantly increases glucose carbon incorporation into tissue polysaccharide.

On a microcolumn of neutral alumina, long-chain fatty acids are quantitatively retained. Neutral lipids including cholesteryl esters, triglycerides, diglycerides, and fatty acid methyl esters, as well as cholesterol, are quantitatively recovered in the effluent without hydrolysis of ester groups. Monoglyceride recovery is, however, only 96 ± 2%. Preparation of the column and chromatography may be accomplished in less than 45 min.

SummaryEpinephrine increases glucose uptake of adipose tissue incubated in vitro. This effect is common to both insulin and epinephrine. However, epinephrine increases and insulin decreases release of free fatty acids. It would appear that the effect of epinephrine on mobilization of free fatty acids is not mediated by a decrease in carbohydrate availability, but possibly by increased rate of glyceride breakdown.

The metabolism of C14-labeled glucose, fructose, mannose and pyruvate was studied in kidney slices from normal and alloxan-diabetic rats. Labeled carbon was recovered in CO2, glycogen and fatty acids. The rate of mannose metabolism was consistently slightly less than that of glucose, and on the other hand, the rate of fructose metabolism was consistently greater. In slices from alloxan-diabetic animals the metabolism of glucose and mannose was markedly reduced; that of fructose was only slightly decreased. No effect of insulin added in vitro could be demonstrated on glucose metabolism. Pyruvate oxidation to CO2 was slightly increased in slices from diabetic animals. Furthermore, glucose production was increased sixfold by diabetes and, as calculated, 75% of this glucose production could be accounted for by glucose synthesized from labeled pyruvate. The similarity between carbohydrate metabolism in liver and kidney was pointed out.

The in vitro survival of ejaculated and epididymal goat sperm was measured in a milk diluent while being incubated at + 37 degrees C and after having been exposed to seminal plasma or to its components. Non-breeding season seminal plasma had a negative effect on sperm survival whether the cells were cooled to + 20 degrees C, chilled to + 4 degrees C or deep-frozen (- 196 degrees C) before being incubated at + 37 degrees C. Bulbo-urethral gland secretions also had a deleterious effect on the survival of washed ejaculated and epididymal sperm cooled to + 20 degrees C. The deleterious effect of the bulbo-urethral secretions on sperm survival and motility was significantly inhibited by the vesicular secretions. Non-breeding season seminal plasma contained bulbo-urethral but little or no vesicular secretions. The non-inhibition of their negative effect(s) may explain that of non-breeding season seminal plasma. Breeding season and non-breeding season washed ejaculated sperm had a better survival and a better motility than those incubated with breeding season seminal plasma. The mild washing procedure used may be responsible for the incomplete removal of seminal plasma from the sperm environment, namely that of the negative factors of the bulbo-urethral secretions. Breeding season seminal plasma would thus simply inhibit the effect of these negative factors or the factors themselves. This hypothesis is supported by the fact that breeding season seminal plasma had no effect on the survival of epididymal sperm.

Free fatty acid mobilization and glucose metabolism to CO2, to glyceride-glycerol, to fatty acids and to glycogen by adipose tissue in vitro were studied in genetically obese hyperglycemic mice (O-H), in goldthioglucose-injected obese Swiss mice and in their respective nonobese littermates. Tissue from O-H mice metabolizes less glucose than tissue from their nonobese littermates in absence of added hormone or in the presence of insulin (0.1 unit/ml) or epinephrine (10–4 m). In addition, there is also a diminished ability for insulin to inhibit and for epinephrine to augment free fatty acid release. No such differences were observed between tissues from goldthioglucose-injected obese Swiss mice and tissues from their lean littermates. Possible significance of these in vitro results with regard to the pathogenesis of the obese hyperglycemic syndrome is discussed.

Adipose tissue metabolism in vitro was studied, after substitution for several weeks of synthetic low-carbohydrate, high-fat (saturated or unsaturated) diets for the standard chow diet, in obese hyperglycemic mice and in their nonobese littermates. In tissue from nonobese mice fed the high-fat diets, glucose metabolism to CO2 and to fatty acids was diminished in the absence of added hormone, while glucose carbon incorporation to glyceride-glycerol was increased. Under insulin (0.1 unit/ml) stimulation, total glucose uptake was relatively decreased by the diets, as was glucose metabolism to CO2, to fatty acids, and to glycogen; however, glucose carbon incorporation to glyceride-glycerol was unaltered. Under epinephrine stimulation, the sum of glucose carbon recovery was less after high-fat feeding. No effect of high-fat feeding was detected on base-line rates of free fatty acid release nor on the effects of insulin or epinephrine on this process. No differences were found between the effects of saturated- or unsaturated-fat diets on any parameters. The metabolism of adipose tissue from obese mice was slightly, if at all, affected by high-fat feeding. These results are discussed in reference to the normal adaptation to low-carbohydrate, high-fat diets and to the metabolic abnormalities present in obese hyperglycemic mice.

A closed perfusion system was designed to study C14O2 formation during uptake of glucose-U-C14 by the isolated, beating rat heart. An initial period of 5 min of preperfusion with oxygenated buffer allowed stabilization of the heart before 30 min of perfusion in the closed recirculation system. Oxygenation was adequate as judged by cardiac rate and force, the pattern of glucose metabolism, the rate of glycogenolysis, and the perfusate oxygen content. Glucose uptake increased sharply with increasing perfusate glucose concentrations over the range 1.25– 5 mm glucose, with a lesser rise in the 5–10 mm range and very little rise from 10–40 mm. Glucose oxidation, which accounted for 60% of the glucose uptake at 1.25 mm glucose concentration, reached a maximal rate at 5–10 mm. This maximal rate accounted for only 24% of the glucose uptake at 40 mm, indicating the increasing importance of nonoxidative fates of glucose with increasing glucose uptake. Lactate and net glycogen formation, and incorporation of glucose carbon into glycogen, were least at lowest glucose concentrations and increased irregularly as the glucose concentration rose. Uptake and oxidation of fructose-U-C14 (5 mm) was much less than that of glucose.

International audience; Avant d’entrer dans l’histoire de chacune des régions caprines, nous retraçons dans cette partie introductive les grandes transformations qui ont marqué la France rurale et affecté la production caprine depuis la fin du 19 è siècle.Nous distinguerons trois périodes, la fin de la paysannerie (avant 1960), la modernisation de l’agriculture et de l’élevage et l’industrialisation de la transformation laitière, mais aussi le retour à la terre dans certaines régions (de 1960 à 1990), ainsi que de l’époque actuelle marquée par un double mouvement de globalisation des échanges et de territorialisation des activités ainsi que par le développement des questions environnementales et de bien-être animal (depuis 1990).