No description available.

Titre de l'écran-titre (visionné le 19 mars 2024) / La méthode d'alimentation en gestation constitue un facteur incontournable de la gestion de la reproduction porcine. Généralement, dans les élevages porcins, les truies sont alimentées avec un seul aliment de composition nutritionnelle fixe pendant toute la gestation, entraînant un manque d'adéquation entre les apports alimentaires et leurs besoins nutritionnels. Ceci se répercute non seulement sur les performances de croissance et reproductives des truies, mais agirait aussi sur les performances zootechniques des porcelets jusqu'après leur sevrage. Outre l'alimentation, la parité des truies est aussi un facteur important exerçant également des influences considérables sur les truies et leur progéniture. L'objectif de ce projet de recherche était de valider l'impact de l'alimentation de précision (AP) et de la stratégie « bump feeding » (BF) en gestation chez des truies durant leurs parités 1 à 3 sur leurs performances à la mise-bas et au sevrage ainsi que les performances de croissance en post-sevrage de leurs porcelets. Une bande de 135 truies a été suivie de leur première parité jusqu'à leur troisième parité et 100 porcelets issus à chacune de ces trois parités ont été suivis en post-sevrage. Quatre traitements isoénergétiques ont été comparés : deux stratégies d'alimentation à concentration constante en nutriments (0,53 % lysine digestible iléale standardisée (Lys DIS)) dont l'apport en quantité était soit constant (FF ; « Flat feeding ») ou variable (BF avec un apport moindre avant 90 jours de gestation puis plus élevé ensuite) et deux stratégies d'alimentation de précision basées sur le modèle InraPorc appliqué par rang de portée (APP) ou en considérant le poids individuel des truies à la saillie (API). Le gain de poids en gestation (saillie à la mise-bas) a augmenté du rang de portée 1 à 3 et il était plus élevé pour le traitement APP (56,94 kg) comparativement au BF (51,94 kg) avec des valeurs intermédiaires pour les traitements FF et API (P < 0,036). L'épaisseur de gras dorsal à la saillie était plus élevée au premier rang de portée comparativement au rang de portées deux et trois (P < 0,001), mais n'a pas été modifiée par les traitements. Les meilleures performances à la mise-bas et au sevrage (nés vivants par portée, poids de portée naissance et au sevrage) ont été obtenues chez les truies à leur 3$^\textup{e}$ parité. Les stratégies alimentaires en gestation ont eu peu d'effets sur les performances à la mise bas et au sevrage des portées. Seulement, le pourcentage de mortalité 24 h-sevrage était globalement plus faible pour le traitement APP et plus élevé pour le traitement API alors que pour les traitements FF et BF, un pourcentage plus élevé était seulement observé en parité trois. Les deux stratégies d'apport énergétique, soit BF et FF, étaient similaires en matière de performances reproductrices à la mise bas et au sevrage, la stratégie FF semblant toutefois mener à de meilleures performances de croissance en post sevrage (meilleur gain, déposition en os et en maigre). Cette étude a donc permis de montrer qu'il ne semble pas être recommandé d'augmenter l'apport en aliment en fin de gestation pour optimiser les performances des truies et de leur progéniture. L'alimentation de précision n'a pas permis d'améliorer les performances reproductives des truies à la mise bas et au sevrage, mais pourrait être efficace à réduire les rejets d'azote et de phosphore dans les lisiers. D'autres études sont toutefois nécessaires pour confirmer ce point.

Thèse de doctorat : Sciences du Vivant. Aspects moléculaires et cellulaires de la Biologie : Strasbourg 1 : 2007. / Titre provenant de l'écran-titre. Bibliogr. 22 p.

The objective was to examine effects of melatonin supplementation during late gestation on uterine artery hemodynamics, offspring growth, and endocrine profiles. Prior to day 170 of gestation, heifers were trained to the Calan feeding system. On day 190 of gestation, heifers (n = 20) were blocked by BW and then randomly assigned to one of two dietary treatments: 1) 20 mg of dietary melatonin per day (MEL) or 2) no melatonin supplementation (CON). Supplementation ceased on day 262 of gestation. A main effect (P < 0.01) of treatment was observed for total uterine artery blood flow with it being increased in MEL vs. CON. An interaction (P = 0.008) was observed in calf body weight increasing at weeks 8 and 9 in MEL vs. CON. Dietary melatonin could be used to potentially increase uterine blood flow and calf body weight.

Introduction Neonatal mortality and morbidity from premature birth are still a major concern despite significant advances in perinatal medicine. Objective of the study The primary aim of the study was to establish the feasibility of accurately identifying a cohort of vvomen at increased risk of preterm birth using a modified risk assessment score and fetal fibronectin testing in order to undertake a pilot randomised placebo-controlled trial of nifedipine as a tocolytic. Methodology A population of pregnant women was screened prospectively between 24 and 34 weeks of gestation using a modified risk assessment system. Women identified as high-risk for preterm birth were then tested with fetal fibronectin. Those testing positive were randomised to either nifedipine or placebo. The study at this point was randomised, placebo-controlled and double-blind. Measures of outcome were compared for babies of trial vvomen with high-risk women who withheld consent. Main outcome measures Delivery before 34 weeks, neonatal death, admission to the Special Care Baby Unit (SCBU), chronic lung disease and major cerebral abnormality on ultrasound scan constituted the main measures of outcome. Results Five hundred and thirty four vvomen were identified as high-risk for preterm birth. One hundred and forty two women agreed to participate in the study. Forty nine women delivered before 37 weeks' gestation. The system was sensitive in predicting preterm birth before 34 weeks of gestation and within one week of testing for fetal fibronectin in symptomatic women. Babies of non-consenting mothers fared better overall than babies of the trial women. Conclusion Risk factor scoring and fetal fibronectin testing are useful screening tools that can predict preterm delivery. This sysytem can be clinically useful in the management of preterm labour or women at increased risk for preterm birth. There was no impact on the neonatal mortality or morbidity.

No description available.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Previous research has shown that the productivity of sows housed in an Electronic Sow Feeding (ESF) system is affected by the housing management (static vs. dynamic), stage of gestation at mixing and parity. Familiarity has also been shown to affect the behaviour of group-housed sows. Thus, the objective of this experiment was to determine how the previously mentioned social factors affect the behaviour, physiology and productivity of sows housed in an ESF system. Sows were regrouped into either the static and dynamic pens. Within an introduction group, a subgroup of up to 24 focals sows was observed. The focal sows were chosen based on whether they were mixed pre vs. post-implantation (<12 vs. >46 days post-breeding), familiar vs. unfamiliar with group mates and parity (1st vs. 2nd and 3rd vs. 4th +). Aggression at mixing and at the feeder, injury scores, feeder entry order, space usage, salivary cortisol and farrowing productivity was recorded. The data was analyzed using Proc-Mixed and the General Model for SAS. Housing did not have a significant effect on the any of the parameters examined. Young sows had significantly more piglets born alive when housed in a dynamic system, while old sows had more piglets born alive when housed in a static system (p=0.03). Pre-implant sows initiated more aggressive encounters than post-implant sows (p=0.01). Post-implant sows ate later in the feeding cycle (p=0.03), rested on the slats more (p<0.001) and had higher salivary cortisol concentrations (p=0.0008). However, the cortisol concentrations increased throughout gestation for all sows (p<0.001). Familiarity did not have an effect on any of the variables examined except, familiar sows spent more time lying against the wall (p=0.03) and unfamiliar sows spent more time lying in the centre of the solid area of the pen (p=0.02). Old sows were involved in more aggressive encounters (p=0.04), spent more time fighting at mixing (p=0.02) and laid against the wall more (p<0.001). Young sows tended to received more scratches (p=0.07), ate later in the feeding cycle (p<0.001) and spent more time lying on the slats (p<0.001). Intermediate sows had significantly lower salivary cortisol concentrations (p=0.003). There was not a difference between the static and dynamic management systems. Sows should not be mixed until after embryonic implantation because they are more docile. The intermediate sows underwent the least amount of social stress due to their intermediate position within the dominance hierarchy.

Previous research has shown that the productivity of sows housed in an Electronic Sow Feeding (ESF) system is affected by the housing management (static vs. dynamic), stage of gestation at mixing and parity. Familiarity has also been shown to affect the behaviour of group-housed sows. Thus, the objective of this experiment was to determine how the previously mentioned social factors affect the behaviour, physiology and productivity of sows housed in an ESF system. Sows were regrouped into either the static and dynamic pens. Within an introduction group, a subgroup of up to 24 focals sows was observed. The focal sows were chosen based on whether they were mixed pre vs. post-implantation (<12 vs. >46 days post-breeding), familiar vs. unfamiliar with group mates and parity (1st vs. 2nd and 3rd vs. 4th +). Aggression at mixing and at the feeder, injury scores, feeder entry order, space usage, salivary cortisol and farrowing productivity was recorded. The data was analyzed using Proc-Mixed and the General Model for SAS. Housing did not have a significant effect on the any of the parameters examined. Young sows had significantly more piglets born alive when housed in a dynamic system, while old sows had more piglets born alive when housed in a static system (p=0.03). Pre-implant sows initiated more aggressive encounters than post-implant sows (p=0.01). Post-implant sows ate later in the feeding cycle (p=0.03), rested on the slats more (p<0.001) and had higher salivary cortisol concentrations (p=0.0008). However, the cortisol concentrations increased throughout gestation for all sows (p<0.001). Familiarity did not have an effect on any of the variables examined except, familiar sows spent more time lying against the wall (p=0.03) and unfamiliar sows spent more time lying in the centre of the solid area of the pen (p=0.02). Old sows were involved in more aggressive encounters (p=0.04), spent more time fighting at mixing (p=0.02) and laid against the wall more (p<0.001). Young sows tended to received more scratches (p=0.07), ate later in the feeding cycle (p<0.001) and spent more time lying on the slats (p<0.001). Intermediate sows had significantly lower salivary cortisol concentrations (p=0.003). There was not a difference between the static and dynamic management systems. Sows should not be mixed until after embryonic implantation because they are more docile. The intermediate sows underwent the least amount of social stress due to their intermediate position within the dominance hierarchy.

Master of Science / Department of Animal Sciences and Industry / Robert D. Goodband / A study was conducted on a commercial sow farm to determine the effects of parity and stage of gestation on growth and feed efficiency of gestating sows. These data were also used to model changes in composition of maternal weight gain and products of conceptus throughout gestation. Feed intake and BW were measured daily from d 5 to 112 of gestation for 712 females. From d 5 to 39 of gestation, ADFI was lowest for parity 3+ sows compared to the other periods of gestation. Parity 2 sows, although provided the same feed allowance, had greater ADFI during the first period than parity 3+ sows. Average daily gain was lowest and G:F was the poorest from d 5 to 39 for each parity group compared with d 40 to 109 of gestation. Parity 1 and 2 sow ADG increased following d 39 of gestation but decreased from d 75 to 109. Parity 3+ sow ADG increased in each subsequent period of gestation. Parity 1 sows had the greatest ADG and G:F in comparison to parity 2 and 3+ sows in each period of gestation. Energy available for maternal growth was estimated after accounting for the energy needed to meet the sow’s maintenance requirement and the energy required for the growth of the conceptus. Following d 39 of gestation, energy available for maternal growth decreased at the expense of maintenance and conceptus requirements in each subsequent period of gestation for each parity group. After accounting for the weight of the conceptus, maternal ADG decreased from d 39 to 74, and increased d 74 to 109 of gestation, regardless of parity. Maternal G:F was greatest for parity 1 sows in most gestation periods. In conclusion, parity and stage of gestation impact sow feed efficiency and maternal growth with parity 1 sows having the greatest weight gain and best feed efficiency.