Artificial selection of the domestic pig (Sus scrofa domesticus) offers a useful model for invest... more Artificial selection of the domestic pig (Sus scrofa domesticus) offers a useful model for investigating changes in behaviour associated with reproductive trade-offs between litter size and fitness of offspring. The aim of this study was to evaluate effects of litter size on teat stimulation, sibling competition, and pre-weaning survival and growth in three populations of domestic pigs subjected to different selection pressures (a maternal line selected for high reproductive investment, a paternal line selected for meat production traits, and a crossbred line). We predicted that, with increasing litter size, piglets would spend more time in udder massage, be less likely to gain access to a teat during milk letdown and, if surviving to weaning, have lower, more variable body weights. We also predicted that maternal line sows would wean more piglets of higher weight, despite larger litter sizes, than paternal line sows. Sows (maternal line, n=12, paternal line, n=12, crossbred line, n=14) were loose-housed with their litters in individual farrowing pens. We collected data on piglet behaviour during nursings at 1 day of age, when sibling competition was expected to be most intense. Piglets were weaned at 35 days of age, when they were weighed and cumulative mortality was calculated. As predicted, piglets in larger litters spent more time in pre- and post-letdown udder massage (P = 0.050 and P < 0.001, respectively). In larger litters, more piglets survived to weaning (P = 0.002), but at a cost of a lower proportion of nursings with letdown (P < 0.001), longer nursing intervals on average (P = 0.018), more piglets without a functional teat at letdown (P < 0.001), an increased risk of mortality due to starvation (P < 0.001) and crushing (P = 0.002), and lower (P = 0.039), more variable (P = 0.002) body weights at weaning. In the maternal line, nursing intervals lengthened with increasing litter size (litter size × breed: P < 0.001) despite more post-letdown udder massage (P < 0.001), and mortality due to crushing rose with increasing litter size (P < 0.001), without differential increments in number, weight or weight uniformity of weaned piglets with increasing litter size between breeds (litter size × breed: P > 0.1). Our results suggest that further artificial selection for larger litters in maternal lines will be unsustainable because increments in the number of piglets weaned have increasing costs (e.g. sibling competition, mortality, uneven growth) that compromise piglet welfare and fitness.
The primary aim of our work was to find maternal behaviours important for piglet survival and to ... more The primary aim of our work was to find maternal behaviours important for piglet survival and to develop qualitative scores of those traits. Second, we studied the relationship between maternal behavioural scores, piglet mortality and the number of weaned piglets in sows of three different sow breeds (Norsvin Landrace (n=12), Norsvin Duroc (n=12) and crossbred Norsvin Landrace × Yorkshire (n=14)). The following qualitative maternal behaviours were scored as follows: nest building activities prior to farrowing, sow communication (q_SC), and carefulness (q_SCR) on while sows were standing, moving and just before lying down. We also continuously recorded maternal care behaviors (nest building activities (c_NBA) and sow communication (c_SC; while standing/moving, before lying down) to test the relationship with the respective qualitative scores. There was a moderate positive correlation between the continuous measured c_NBA and the qualitative score for nest building q_NBA (r = 0.469) as well as between the qualitative score for communication, q_SC and the continuous, video-based measure of communication while standing, c_SC (r = 0.439), and the qualitative and quantitative scores similarly affected piglet survival. Since q_SC and q_SCR were highly correlated (r = 0.883), we tested the effect of those behavioural scores separately on production parameters (proportion of dead piglets and number of weaned piglets) using two models (model 1: q_NBA, q_SC; model 2: q_NBA, q_SCR), and compared their relative predictive accuracies using Akaike information criteria (AIC) and AIC weights. In models 1 and 2, piglet mortality decreased with higher q_NBA (P = 0.004; P < 0.001; respectively) due to less crushing (P < 0.001; P < 0.001, respectively) and, thus, more weaned piglets (P = 0.043; P = 0.035; respectively). Increases in both q_SC and q_SCR were associated with lower overall piglet mortality (P < 0.001; P < 0.001, respectively), fewer crushing incidences (P < 0.001; P = 0.002, respectively) and, therefore, more weaned piglets (P = 0.004; P = 0.030; respectively). Additionally, higher q_SC in model 1 was associated with a lower proportion of starved piglets (P = 0.002). Model 1 had better predictive accuracy than model 2 for all productive parameters. Our results demonstrated that our three defined maternal behaviour scores had a significant impact on piglet survival, and therefore we would like to proceed with testing of these scores in nucleus herds of Norsvin Landrace sows to further calculate heritabilities and potentially implement the most successful behavioural trait in the breeding program.
ABSTRACT The aim of this experiment was to study the effects of six different management routines... more ABSTRACT The aim of this experiment was to study the effects of six different management routines at the time of farrowing on latency to first suckle, heat loss, weight gain and postnatal mortality. A total of 872 piglets from 67 loose housed sows in a commercial pig unit were subjected to one of six different management routines: control (CON n=14), no treatment; (CREEP n=13), placed in creep area; (UDDER n=10), placed at the udder; (DRY n=10), dried and placed back where found; (DRYCREEP n=9), dried and placed in creep area; and (DRYUDD n=11), dried and placed at the udder. The latency from birth to first suckle, rectal temperature at birth, 2hours and 24hours were measured for each piglet, in addition to weight at birth, 2hours and 24hours. Latency from birth to first suckle was shortest for piglets in the DRYUDD treatment, followed by the UDDER treatment (P
The behavioural and physiological responses of pregnant sows to cold exposure in a kennel system ... more The behavioural and physiological responses of pregnant sows to cold exposure in a kennel system were investigated. Ten groups, each of six pregnant sows, were housed over winter in a non-insulated building containing kennels. Lying posture, social thermoregulation, time spent inside the kennels and general activity were recorded in three 48-h periods with different diurnal room temperatures: cold (−9 to −1 °C), medium (0 to +3 °C) and warm (+4 to +9 °C). Blood samples were collected from two of the groups, and the concentrations of glucose, free fatty acids, total thyroxine (TT4) and free thyroxine (FT4) in the plasma were determined.The air temperature difference in between the surrounding room and the kennels increased with decreasing room temperature with a maximum of 12 °C at a room temperature of −10 °C. Activity level did not differ significantly between temperature periods (30.6 ± 1.1%). At all temperature periods, the sows spent between 80 and 90% of their time inside the k...
Artificial selection of the domestic pig (Sus scrofa domesticus) offers a useful model for invest... more Artificial selection of the domestic pig (Sus scrofa domesticus) offers a useful model for investigating changes in behaviour associated with reproductive trade-offs between litter size and fitness of offspring. The aim of this study was to evaluate effects of litter size on teat stimulation, sibling competition, and pre-weaning survival and growth in three populations of domestic pigs subjected to different selection pressures (a maternal line selected for high reproductive investment, a paternal line selected for meat production traits, and a crossbred line). We predicted that, with increasing litter size, piglets would spend more time in udder massage, be less likely to gain access to a teat during milk letdown and, if surviving to weaning, have lower, more variable body weights. We also predicted that maternal line sows would wean more piglets of higher weight, despite larger litter sizes, than paternal line sows. Sows (maternal line, n=12, paternal line, n=12, crossbred line, n=14) were loose-housed with their litters in individual farrowing pens. We collected data on piglet behaviour during nursings at 1 day of age, when sibling competition was expected to be most intense. Piglets were weaned at 35 days of age, when they were weighed and cumulative mortality was calculated. As predicted, piglets in larger litters spent more time in pre- and post-letdown udder massage (P = 0.050 and P < 0.001, respectively). In larger litters, more piglets survived to weaning (P = 0.002), but at a cost of a lower proportion of nursings with letdown (P < 0.001), longer nursing intervals on average (P = 0.018), more piglets without a functional teat at letdown (P < 0.001), an increased risk of mortality due to starvation (P < 0.001) and crushing (P = 0.002), and lower (P = 0.039), more variable (P = 0.002) body weights at weaning. In the maternal line, nursing intervals lengthened with increasing litter size (litter size × breed: P < 0.001) despite more post-letdown udder massage (P < 0.001), and mortality due to crushing rose with increasing litter size (P < 0.001), without differential increments in number, weight or weight uniformity of weaned piglets with increasing litter size between breeds (litter size × breed: P > 0.1). Our results suggest that further artificial selection for larger litters in maternal lines will be unsustainable because increments in the number of piglets weaned have increasing costs (e.g. sibling competition, mortality, uneven growth) that compromise piglet welfare and fitness.
The primary aim of our work was to find maternal behaviours important for piglet survival and to ... more The primary aim of our work was to find maternal behaviours important for piglet survival and to develop qualitative scores of those traits. Second, we studied the relationship between maternal behavioural scores, piglet mortality and the number of weaned piglets in sows of three different sow breeds (Norsvin Landrace (n=12), Norsvin Duroc (n=12) and crossbred Norsvin Landrace × Yorkshire (n=14)). The following qualitative maternal behaviours were scored as follows: nest building activities prior to farrowing, sow communication (q_SC), and carefulness (q_SCR) on while sows were standing, moving and just before lying down. We also continuously recorded maternal care behaviors (nest building activities (c_NBA) and sow communication (c_SC; while standing/moving, before lying down) to test the relationship with the respective qualitative scores. There was a moderate positive correlation between the continuous measured c_NBA and the qualitative score for nest building q_NBA (r = 0.469) as well as between the qualitative score for communication, q_SC and the continuous, video-based measure of communication while standing, c_SC (r = 0.439), and the qualitative and quantitative scores similarly affected piglet survival. Since q_SC and q_SCR were highly correlated (r = 0.883), we tested the effect of those behavioural scores separately on production parameters (proportion of dead piglets and number of weaned piglets) using two models (model 1: q_NBA, q_SC; model 2: q_NBA, q_SCR), and compared their relative predictive accuracies using Akaike information criteria (AIC) and AIC weights. In models 1 and 2, piglet mortality decreased with higher q_NBA (P = 0.004; P < 0.001; respectively) due to less crushing (P < 0.001; P < 0.001, respectively) and, thus, more weaned piglets (P = 0.043; P = 0.035; respectively). Increases in both q_SC and q_SCR were associated with lower overall piglet mortality (P < 0.001; P < 0.001, respectively), fewer crushing incidences (P < 0.001; P = 0.002, respectively) and, therefore, more weaned piglets (P = 0.004; P = 0.030; respectively). Additionally, higher q_SC in model 1 was associated with a lower proportion of starved piglets (P = 0.002). Model 1 had better predictive accuracy than model 2 for all productive parameters. Our results demonstrated that our three defined maternal behaviour scores had a significant impact on piglet survival, and therefore we would like to proceed with testing of these scores in nucleus herds of Norsvin Landrace sows to further calculate heritabilities and potentially implement the most successful behavioural trait in the breeding program.
ABSTRACT The aim of this experiment was to study the effects of six different management routines... more ABSTRACT The aim of this experiment was to study the effects of six different management routines at the time of farrowing on latency to first suckle, heat loss, weight gain and postnatal mortality. A total of 872 piglets from 67 loose housed sows in a commercial pig unit were subjected to one of six different management routines: control (CON n=14), no treatment; (CREEP n=13), placed in creep area; (UDDER n=10), placed at the udder; (DRY n=10), dried and placed back where found; (DRYCREEP n=9), dried and placed in creep area; and (DRYUDD n=11), dried and placed at the udder. The latency from birth to first suckle, rectal temperature at birth, 2hours and 24hours were measured for each piglet, in addition to weight at birth, 2hours and 24hours. Latency from birth to first suckle was shortest for piglets in the DRYUDD treatment, followed by the UDDER treatment (P
The behavioural and physiological responses of pregnant sows to cold exposure in a kennel system ... more The behavioural and physiological responses of pregnant sows to cold exposure in a kennel system were investigated. Ten groups, each of six pregnant sows, were housed over winter in a non-insulated building containing kennels. Lying posture, social thermoregulation, time spent inside the kennels and general activity were recorded in three 48-h periods with different diurnal room temperatures: cold (−9 to −1 °C), medium (0 to +3 °C) and warm (+4 to +9 °C). Blood samples were collected from two of the groups, and the concentrations of glucose, free fatty acids, total thyroxine (TT4) and free thyroxine (FT4) in the plasma were determined.The air temperature difference in between the surrounding room and the kennels increased with decreasing room temperature with a maximum of 12 °C at a room temperature of −10 °C. Activity level did not differ significantly between temperature periods (30.6 ± 1.1%). At all temperature periods, the sows spent between 80 and 90% of their time inside the k...
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