Knut Egil Bøe

Grouping and social preferences in calves, heifers and cows

In order to improve animal welfare, a growing number of calves, heifers and dairy cows are reared in loose housing systems. However, (re)grouping unfamiliar animals may result in aggressive interactions and distress, especially for low ranked animals. Grouping of unfamiliar animals is found to increase aggression, social stress, locomotion behaviour and to have negative effects on feed intake and milk yield. Problems related to social integration are normally higher for the introduced animals than the resident animals. Previous social experience, number of animals that are mixed and the group composition are important factors that can influence social integration. Calves reared in groups are more social confident and show less fear than calves reared in single boxes or in isolation. Repeated grouping seem to accustom the animals to these procedures. Increased knowledge about social integration is necessary to develop effective management techniques that reduce the amount of problems occurring during social integration of cattle.

The effects of weight asymmetry and resource distribution on aggression in groups of unacquainted pigs

The relationship between weight asymmetry and aggression when mixing groups of unacquainted pigs in two different environments was investigated. Ten groups of 4 female (LandracexYorkshire), unacquainted pigs with a weight asymmetry of 3.1+/-0.2 kg (mean weight: 16.6+/-0.6 kg) between each pig, and another 10 groups with a weight asymmetry of 1.2+/-0.1 kg (mean weight: 14.1+/-0.1 kg), were mixed at the age of 7 weeks. Ten of the groups (five of each) were mixed in an experimental pen with a heterogeneous distribution of straw. The pen consisted of two main compartments with straw in one of them, and a passage area with concrete floor in between. The other 10 groups were mixed in the same pen, but with a homogenous distribution of straw (straw spread all over the pen).The results showed that fighting duration was significantly shorter in groups with large weight asymmetry than in groups with small weight asymmetry irrespective of the environment. The number of bites delivered during the fights in the heterogeneous environment was lower in groups with large weight asymmetry than in groups with small weight asymmetry. In the homogenous environment, however, there was no significant difference between groups with large and small weight asymmetries regarding the number of bites. The combination of a limited straw area and a small weight asymmetry resulted in the greatest number of bites. In groups with large weight asymmetry, the largest pig won around 50% of the fights, and 25% of the variation in the percentage of fights won was explained by the weight asymmetry.In groups with small weight asymmetry, less than 10% of the variation in the percentage of fights won could be explained by weight asymmetry. The two largest pigs delivered significantly more bites and spent significantly more time fighting than the smallest pig. The second largest pig received significantly more bites and body lesions than the smallest pig in the groups. Fights between the two largest pigs had a significantly longer duration than when other pigs were involved. The results were discussed in relation to sequential assessment theory and resource defence theory.

The process of weaning in pigs: when the sow decides

Abstract The aim of this experiment was to study the process of weaning in pigs and the effect of parity and litter size on this process. Behaviour was observed and weight gain and feed intake were recorded every week until 10 weeks postpartum for 22 litters and their dams in a special pen unit designed so that the sow could leave the piglets. The body weight of the piglets increased gradually to 29.89 kg at 10 weeks, and the intake of dry feed was low until Week 5, after which it increased rapidly. The time the sows spent with the piglets decreased gradually from 791±303 min per 24-h period at Week 2 to 142±265 min per 24-h period at Week 10. The number of sucklings per 24-h period decreased from 22.9±5.2 to 4.3±5.2, respectively. Half the sows weaned their young before 10 weeks. The sows increased their time away from the piglets during the day, but still preferred to stay with the piglets during the night. At 2 weeks the piglets initiated the majority (nearly 80%) of the sucklings and this increased to over 90% at 10 weeks. The proportion of initiated sucklings where the piglets were lying together with the sow decreased, and the proportion where sows were standing during suckling increased. The proportion of sucklings terminated by the sows increased from 50% at 2 weeks to nearly 90% at 10 weeks. The way in which suckling was initiated and terminated also varied over the 24-h period. Parity did not seem to affect the weaning process, but small litters were weaned later and had a higher body weight at 10 weeks.

Maternal investment, sibling competition, and offspring survival with increasing litter size and parity in pigs (Sus scrofa)

The aim of this study was to examine the effects of litter size and parity on sibling competition, piglet survival, and weight gain. It was predicted that competition for teats would increase with increasing litter size, resulting in a higher mortality due to maternal infanticide (i.e., crushing) and starvation, thus keeping the number of surviving piglets constant. We predicted negative effects on weight gain with increasing litter size. Based on maternal investment theory, we also predicted that piglet mortality would be higher for litters born late in a sows life and thus that the number of surviving piglets would be higher in early litters. As predicted, piglet mortality increased with increasing litter size both due to an increased proportion of crushed piglets, where most of them failed in the teat competition, and due to starvation caused by increased sibling competition, resulting in a constant number of survivors. Piglet weight at day 1 and growth until weaning also declined with increasing litter size. Sows in parity four had higher piglet mortality due to starvation, but the number of surviving piglets was not affected by parity. In conclusion, piglet mortality caused by maternal crushing of piglets, many of which had no teat success, and starvation caused by sibling competition, increased with increasing litter size for most sow parities. The constant number of surviving piglets at the time of weaning suggests that 10 to 11 piglets could be close to the upper limit that the domestic sow is capable of taking care of.

The influence of different feeding arrangements and food type on competition at feeding in pregnant sows

Abstract The effects of different feeding arrangements (body, shoulder and no partitions between sows) and type of food (wet vs. dry) on aggressive competition at feeding were investigated. Six groups of six pregnant sows were subjected to all the six treatments, and the order of treatments were rotated systematically. In the last 2 days of each treatment period (lasting for 9 days in total), the behaviour of the sows was video recorded for 60 min from the start of feeding. Aggressive behaviours (bite towards head/shoulder and body, bite towards vulva, push, threat, head knock), frequency of changing position at the trough (displacements and voluntary changes of position) and the time at trough were recorded. In the analysis, the observation period was divided into feeding (0–15) and post feeding (45–60 min). On dry feeding, increasing length of partitions resulted in a significant reduction in the number of bites, total aggressive behaviours and displacements at the trough and an increased time at trough. The number of bites and total aggressive behaviours were lower on wet than on dry feeding in the simple feeding arrangements (i.e., shoulder or no partitions), but there were no significant differences when body partitions were used. On wet feeding, there were no significant differences between body and shoulder partitions concerning the number of bites, nor were there any significant differences between feeding arrangements concerning the time at trough or the number of displacements at trough when wet food was used. The top ranked sows received less bites and displacements and spent more time at trough than the other sows in all feeding arrangements, whereas the lower ranked sows were less subjected to aggression and displacements and spent more time at the trough as the length of partitions increased. In conclusion, a feeding arrangement with body partitions resulted in the least aggression and displacements at trough compared to a situation with shoulder or no partitions. On wet feeding, however, the amount of aggression did not differ between shoulder and body partitions, and the time at trough appeared to be almost equal in all feeding arrangements. Simple feeding systems may thus be used without increasing the amount of aggression or reducing the eating time when wet food is used. However, the differences in eating time, aggression received and displacements between sows of different rank order will increase with decreasing length of partitions at the trough, and in a situation without partitions the low-ranking individuals may suffer from a reduced food intake. Body partitions is therefore still a more recommendable feeding system.

The Effect of Age at Weaning and Post-Weaning Environment on the Behaviour of Pigs

Abstract In order to investigate the effect of age at weaning and the post-weaning environment on the behaviour and health of piglets, litters were weaned at 4 or 6 weeks of age and either kept in their farrowing pen or housed in flat decks (2 × 2 factorial design with a total of 24 litters). At 9 weeks of age all litters were moved to standard pens for fattening pigs. Behavioural observations and recording of lesions were undertaken at 8 and 12 weeks of age. At 8 weeks piglets weaned in flat decks spent more time lying than those weaned in the farrowing pen (1080 vs. 1026 min per day, p <0.01), and piglets weaned at 6 weeks spent more time lying than those weaned at 4 weeks (1083 vs. 1026 min per day, p <0.01). Direct observations showed that piglets weaned in flat decks were sniffing/rooting pen mates, pen fittings and the floor, and chewing/nibbling pen mates and tail-biting significantly more than piglets weaned in the farrowing pen. The age at weaning was of minor importance for the frequency of thes...

Maternal behaviour of lactating sows in a loosehousing system

Abstract The aim of this experiment was to investigate the process of weaning and the motivation of the sow to continue nursing in a system where the sow could leave the piglets and join other sows in a common area; and further to look at the effect of parity and number of piglets in the litter on the weaning process. The behaviour of 16 sows with litters was recorded every week from Week 2 to Week 10 postpartum. Body weight and feed intake of the piglets were also recorded on a weekly basis. In Week 2 the sow spent 775 min day −1 with the piglets (53.8% of the 24-h period), but in Week 4 it was as low as 28 min day −1 (1.9% of the 24-h period). The number of sucklings decreased similarly from 20.4 in Week 2 to 4.8 in Week 4, and nine out of 16 sows had virtually weaned their piglets before 5 weeks postpartum. The proportion of sucklings terminated by the sow had already reached 100% by Week 5. The early weaned litters had a poorer weight gain, and did not increase their intake of concentrates to compensate for the reduced milk transfer. These results suggest that in an integrated system where the sow can leave her piglets and have social interaction with other sows, the bond between mother and offspring is weakened so that weaning can occur very early.

Relationship between postnatal piglet mortality, environmental factors and management around farrowing in herds with loose-housed, lactating sows

Abstract The objective of this study was to investigate management routines and environmental factors influencing postnatal piglet mortality in commercial herds with individually loose-housed sows. Last year production records from 39 herds were used. We gathered information on specific routines as well as environmental factors by visiting every farm once. Herds practising moderate roughage feeding during pregnancy tended to have lower piglet mortality (p=0.06). Use of farrowing rails along all the sides of the pen resulted in lower piglet mortality than when no rails were present (p<0.01). Herds that hardly used any litter in the sow area at the time of farrowing had significantly higher piglet mortality than herds that used a moderate or large amount (p<0.05). Helping the piglets to obtain colostrum immediately after birth also reduced mortality (p<0.05), whereas other routines such as shutting the piglets inside the creep area while feeding the sow did not have any significant effect.

Housing system and herd size interactions in Norwegian dairy herds; associations with performance and disease incidence

BackgroundAccording to the Norwegian animal welfare regulations, it has been forbidden to build new tie-stall barns since the end of 2004. Previous studies have shown that cow performance and health differ between housing systems. The interaction between housing system and herd size with respect to performance and disease incidence has not been evaluated.MethodsCow performance and health in 620 herds housed in free-stall barns were compared with in 192 herds housed in tie-stall barns based on a mail survey and data from the Norwegian Dairy Herd Recording and Cattle Health Systems. The housing systems herds were comparable with respect to herd size (15-55 cows). Associations between performance/disease incidence and housing system, herd size and year of building the cow barn were tested in general linear models, and values for fixed herd size of 20 and 50 cows were calculated. On the individual cow level mixed models were run to test the effect of among others housing system and herd size on test-day milk yield, and to evaluate lactation curves in different parities. All cows were of the Norwegian Red Breed.ResultsAverage milk production per cow-year was 134 kg lower in free-stall herd than in tie-stall herds, but in the range 27-45 cows there was no significant difference in yields between the herd categories. In herds with less than 27 cows there were increasingly lower yields in free-stalls, particularly in first parity, whereas the yields were increasingly higher in free-stalls with more than 45 cows.In free-stalls fertility was better, calving interval shorter, and the incidence rate of teat injuries, ketosis, indigestions, anoestrus and cystic ovaries was lower than in tie-stalls. All of these factors were more favourable in estimated 50-cow herds as compared to 20-cow herds. In the larger herd category, bulk milk somatic cell counts were higher, and the incidence rate of mastitis (all cases) and all diseases was lower.ConclusionThis study has shown that there is an interaction between housing system and herd size, and that performance and health is not universally better in small free-stalls than in tie-stalls.

Drying and warming immediately after birth may reduce piglet mortality in loose-housed sows

The aim of the present experiment was to investigate the effects of placing newborn piglets under the heat lamp or both drying and placing them under the heat lamp on piglet mortality. Sixty-seven healthy (Landrace × Yorkshire) sows were divided equally into three different experimental groups: a control group where the farrowings occurred without supervision from the farmer (C; n = 23 litters), another group where the piglets were placed under the heat lamp in the creep area immediately after birth (HL; n = 22 litters) and a third group where the piglets were dried with straw and paper towels followed by placing them under the heat lamp in the creep area immediately after birth (DHL; n = 22 litters). The sows were individually loose-housed in farrowing pens during farrowing and lactation. The piglets were not closed inside the creep area, but were free to move around in the pen. The routines in the experimental groups required the stock person to attend the farrowings from the onset of birth of the first piglet until the last piglet was born. All the dead piglets were weighed and subjected to a post mortem examination at the farm to ascertain the causes of death. Postnatal mortality (% of live born) was significantly lower in the HL and DHL groups than in the control group (P < 0.0001). This was significant concerning all causes of mortality. Compared to the control group, crushing occurred in significantly fewer litters when the piglets were both dried and placed under the heat lamp (P < 0.05). In the DHL treatment, crushing of one or more piglets by the sow occurred in only 13.6% of the litters, whereas this was increased to 34.8% in the HL and to 47.9% in the control group, respectively. All causes of death, except the proportion of stillborn piglets, increased significantly with increasing litter size. Because of the relatively large potential that these rather simple routines may have to improve piglet survival, different types of management or human interference around the time of farrowing should be compared on a larger scale, both experimentally and on commercial farms.