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Hemsworth P.H.,University of Melbourne | Rice M.,University of Melbourne | Nash J.,University of Melbourne | Giri K.,Australian Department of Primary Industries and Fisheries | And 4 more authors.
Journal of Animal Science | Year: 2013

A total of 3,120 sows, in 4 time replicates, were used to determine the effects of group size and floor space on sow welfare using behavioral, physiological, health, and fitness variables. Within 1 to 7 d postinsemination, sows were assigned randomly to treatments of a 3 by 6 factorial arrangement, with 3 group sizes (10, 30, or 80 sows/pen) and 6 floor space allowances (1.4, 1.8, 2.0, 2.2, 2.4, or 3.0 m2/sow). Sows were housed on partially slatted concrete floors, and over-head feeders delivered 4 times/day to provide a total of 2.5 kg of feed/sow. As pen space increased from 1.4 to 3.0 m2/sow, aggression at feeding decreased from about 9 to 7 bouts/sow (linear, P = 0.029) and plasma cortisol concentrations decreased from about 28 to 21 ng/mL (linear, P = 0.0089) at 2 d. Although the results are in accord with a linear decline from 1.4 to 3 m2/sow, the results are also in accord with a decline in these measurements from 1.4 to 1.8 m2/sow and no further decline greater than 1.8 m2/sow. Farrowing rate (percentage of inseminated sows that farrowed) also increased from about 60 to 75% as space increased from 1.4 to 3.0 m2/ sow (linear, P = 0.012). Group size was related to skin injuries on d 9 (P = 0.0017), 23 (P = 0.0046), and 51 (P = 0.0006), with groups of 10 consistently having the lowest number of total injuries over this period. Based on the aggression and cortisol results, it is credible to judge that, within the range of floor space allowances studied, sow welfare improves with increased space. However, from a sow welfare perspective, the experiment had insufficient precision to determine what is an adequate space allowance for sows. Thus, although the results definitely support a space allowance of 1.4 m2/ sow being too small, it is not possible to give guidance on an actual space allowance at mixing that is adequate. © 2013 American Society of Animal Science. All rights reserved. Source


Stevens B.,University of Melbourne | Karlen G.M.,University of Melbourne | Morrison R.,Rivalea Australia | Gonyou H.W.,Prairie Swine Center Inc. | And 4 more authors.
Applied Animal Behaviour Science | Year: 2015

Confinement of breeding sows to stalls is a controversial welfare issue, and there is a worldwide move to house gestating sows in groups. We examined the effects of day of mixing following insemination on aggression, injuries and stress in sows. A total of 800 sows were used in this experiment and we examined the effects of mixing sows in groups within 1 to 7 days post-insemination (Group0) or at 35 days (36-42 days) post-insemination after housing in stalls from insemination (Group35). Groups of 85 sows were housed on concrete floors covered in rice hulls with a floor space allowance of 2.3m2 per sow. Mixing sows at day 35 post-insemination, instead of early post-insemination, resulted in a reduction (P<0.05) in the frequency of aggressive behaviour (1.4-0.8 bouts per sow) and cortisol concentrations at mixing (5.2-2.5nM) and the number of old injuries (13.2-4.6 injuries per sow) at 7 days after mixing (7 and 42 days post-insemination, respectively). By 7 days after mixing, the frequency of aggressive behaviours and cortisol concentrations were substantially lower than at mixing and there were no differences between the treatments. There were no treatment effects on the ratio of neutrophils to lymphocytes at day 51 post-insemination, cortisol concentrations at day 91 post-insemination, or reproductive performance (farrowing rate and litter size). The results show that the stage of gestation when sows are mixed affects aggression, injuries and stress in sows and that challenges associated with aggression, injuries and stress at mixing are greater early after insemination than later. With the increasing interest in further reducing the period during which sows are housed in stalls, research examining ways of reducing risks to sow welfare and productivity associated with grouping needs to focus on mixing sows both after their piglets are weaned and early after insemination. © 2015 Elsevier B.V. Source


Verdon M.,University of Melbourne | Morrison R.S.,Rivalea Australia | Hemsworth P.H.,University of Melbourne
Applied Animal Behaviour Science | Year: 2016

This experiment investigated the effects of rearing piglets in a multi-litter lactation system on piglet aggression at weaning. The following four pre-weaning treatments were applied to 72 sows and their litters (n=642 piglets); (1) Farrowing crate ('FC' - n=24 sows), (2) PigSAFE pens, in which sows and piglets are loose housed, ('PS' - n=24 sows), (3) Farrowing crate and group lactation ('GLFC' - n=12 sows), and (4) PigSAFE and group lactation ('GLPS' - n=12 sows). FC and PS piglets remained in treatment from birth (day 0) until weaning (day 27). GLFC and GLPS piglets were housed in FC and PS, respectively, from day 0 to 14 after which they were transferred (with their dams) to group lactation pens (n=6 sows and litters/pen), where they remained until weaning. Piglet weights were recorded at day 13 and 26. At weaning piglets were mixed into pens of four litters from FC, PS, or GL (2 GLFC litters and 2 GLPS litters) treatments and behaviour was continuously recorded for 2h. Aggression (reciprocal and non-reciprocal aggression of duration <5s) and fights (reciprocal aggression of duration ≥5s; frequency; total and average duration, latency to fight) were recorded for each litter. Six piglets from each litter were randomly selected for skin lesion scoring on day 26 and 24h post-weaning. GLFC and GLPS piglets had a lower growth rate than FC and PS piglets from day 13 to 26 (P<0.01) but there was no difference in weight at day 13 (P=0.11) or day 26 (P=0.17), or in skin lesions at day 26 (P=0.26). GL piglets delivered fewer bouts of aggression (P<0.01), fought less frequently in the 2h post-mixing at weaning (P<0.01) and had sustained fewer skin lesions 24h later (P<0.01) than FC or PS piglets. GL piglets also had shorter fights (P<0.01) and spent less total time fighting (P=0.04) than FC, but not than PS, piglets. These results highlight the possible importance of the early social environment on the development and regulation of aggressive behaviour in the pig. Due to the implications of aggression and injury on both animal welfare and productivity, there is a need for further investigation into the effects of housing piglets in multi-litter lactation systems. © 2016 Elsevier B.V. Source


Rault J.-L.,University of Melbourne | Morrison R.S.,Rivalea Australia | Hansen C.F.,Copenhagen University | Hansen L.U.,Pig Research Center | Hemsworth P.H.,University of Melbourne
Journal of Animal Science | Year: 2014

This project compared the effects of grouping sows after weaning or within 2 d after insemination on sexual behavior, aggression, injuries, stress, and mating success. At weaning (d 0), 360 sows were housed in groups of 10 sows at 4.4 m2 per sow (group weaned [GpW]) or individual stalls (stall weaned [StW]), with 18 groups per treatment. Six days after weaning (d 6), 7 inseminated GpW sows were moved to pens at 2.1 m2 per sow and keeping acquainted sows, and simultaneously, groups of 7 inseminated StW sows were mixed at 2.1 m2 per sow. Group-weaned sows showed greater variation in the onset of estrus (P = 0.02) but not in the length of estrus compared to StW sows (P = 0.21), with 7% fewer GpW sows inseminated within 5 d of weaning (P = 0.05). Group-weaned sows showed lower sexual receptivity scores, showing less spontaneous standing during boar exposure and partly compensating by a greater response to the back-pressure test (both P < 0.01). The GpW treatment also showed greater variability in sows inseminated twice within 6 d of weaning, with 3 out of 18 pens having only 5 mated sows out of 10. Mixing after weaning resulted in higher levels of stress than mixing after insemination, with GpW sows having higher plasma cortisol concentration than StW sows on d 1 (P < 0.001) but no treatment differences on d 7 in cortisol concentration or aggression at feeding (P = 0.48). Group-weaned sows experienced greater weight loss during the first week postweaning (P = 0.05). Anogenital sniffing in GpW sows was frequently observed from d 2 to 5, but mounting and flank nosing increased on d 4 and 5. Frequency of sexual behavior initiated by GpW sows tended to correlate with weight loss (P = 0.08), and sexual behavior received correlated positively with cortisol concentration at d 1 (P = 0.005). In conclusion, sows housed in groups at weaning and regrouped after insemination experienced higher stress than sows housed in individual stalls at weaning and mixed in groups after insemination. This resulted in lower mating success within 5 d of weaning, which in turn increased between-week variability. The lower sexual receptivity in sows grouped at weaning may be due to suppressed estrus-related behaviour, with ovulation occurring, or delayed ovulation beyond d 6. Further research is needed to identify underlying mechanisms to reduce variability, manage aggression and sexual behavior, and optimize estrus detection in group-housed weaning systems. © 2014 American Society of Animal Science. All rights reserved. Source


Dunshea F.R.,University of Melbourne | Dunshea F.R.,Australian Department of Primary Industries and Fisheries | Cronin G.M.,Australian Department of Primary Industries and Fisheries | Cronin G.M.,University of Sydney | And 12 more authors.
Animal Production Science | Year: 2011

It is generally accepted that entire boars are leaner and more efficient than barrows but that they have poorer meat quality with an increased risk of boar taint. An additional issue in producing boars to meet market specifications is variation in growth performance, which may be exacerbated by high levels of aggression and mounting behaviour in group-housed animals. Immunisation against gonadotrophin-releasing hormone (GnRH), leading to immunological castration, offers a means of reducing aggression and mounting behaviour while maintaining most of the production efficiencies associated with entire boars. A total of 120 control boars, 120 immunised boars and 60 barrows (physically castrated at 5 days of age) were used in a study conducted in two replicates. Each replicate consisted of two pens each of boars, immunised boars and barrows, each pen containing 15 pigs, and two blocks of 15 individually-housed boars and immunised boars. The group-housed pigs had access to two single place electronic feeders per pen. Immunised boars were given the anti-GnRH vaccine (Improvac) at 14 and 18 weeks of age. In the 2 weeks immediately after the secondary immunisation at 18 weeks, average daily gain was greater in the immunised boars than the boars or barrows, particularly in those that were group housed, as indicated by the interaction (P = 0.035). From 18 to 23 weeks of age average daily gain was greater (P = 0.005) in immunised boars than in control boars and barrows and was greater (P <0.001) in individually- than in group-housed pigs. The average daily gain of group-housed immunised boars and individually-housed control boars were similar over the 5-week period after secondary immunisation (1090 vs 1099 g/day), being ∼20 and 15% higher than the group-housed control boars and barrows, respectively. The average daily feed intake was greater (P = 0.011) in immunised boars than in control boars with barrows intermediate. The standard deviation of bodyweight increased with age but was lower (P from 0.032 to 0.09) in immunised boars than in control boars and barrows between 18 and 22 and 17 and 21 weeks of age. Carcass fighting damage and pork pH were higher (P<0.05) for control boars than for immunised boars or barrows. In conclusion, immunisation against GnRH increased average daily gain and average daily feed intake while decreasing variation in bodyweight and improving carcass and pork quality. © 2011 CSIRO. Source

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