C. F. Hansen

THE INFLUENCE OF HANDLING BY HUMANS ON THE BEHAVIOUR, REPRODUCTION AND CORTICOSTEROIDS OF MALE AND FEMALE PIGS

The influence of three handling treatments on the behaviour, reproduction and free corticosteroid concentrations was studied in 15 male and 30 female pigs. Two handling treatments, considered as pleasant and unpleasant, were imposed for 5 min, three times per week from 11 weeks of age. The third handling treatment involved minimal contact with humans from 11 weeks of age. In a 3-min test at 18 weeks, pigs in the pleasant treatment were quicker (P<0.01) to enter an area within 0.5 m of the experimenter and had more interactions (P<0.05) with the experimenter than pigs in the unpleasant and minimal treatments. Gilts in the unpleasant treatment had a lower (P<0.05) pregnancy rate at the second oestrus when mated to non-experimental boars than gilts in the pleasant treatment (33.3 and 87.5%, respectively). Boars in the unpleasant treatment had smaller (P<0.05) testicles at 23 weeks of age and attained a coordinated mating response at a later age (P<0.05) than boars in the pleasant treatment (53.2 and 63.3 cm2, and 192 and 161 days, respectively). In addition, pigs in the unpleasant treatment had higher (P<0.05) free corticosteroid concentrations in the absence of humans at 20 weeks (gilts) and 27 weeks (boars) than pigs in the pleasant treatment (boars and gilts combined, 2.4 and 1.7 ng ml−1, respectively). For many of the reproductive parameters, the effect of the minimal handling treatment was intermediate to that of the other two treatments. It was concluded that the unpleasant handling treatment resulted in a chronic stress response, with consequent adverse effects on reproduction.

The influence of inconsistent handling by humans on the behaviour, growth and corticosteroids of young pigs

The influence of 4 handling treatments on the behaviour, growth and free corticosteroid concentrations were studied in 32 young female pigs housed in individual pens. The pleasant treatment involved stroking the pig whenever it approached the experimenter, the unpleasant treatment involved forcing the pig away whenever it approached the experimenter and the inconsistent treatment was a combination of unpleasant and pleasant treatments (imposed at a ratio of 1:5). These 3 treatments were imposed for 3 min each, 3 times per week, from 7 to 13 weeks of age. The fourth treatment, minimal handling, involved minimal contact with humans during this 6-week period. Gilts in the pleasant and minimal handling treatments had higher (P < 0.05) growth rates and feed conversion efficiencies over the first 2 weeks of the study than gilts in the unpleasant and inconsistent handling treatments. The gilts in the unpleasant and inconsistent handling treatments had higher (P < 0.01) free corticosteroid concentrations in the absence of humans at 14 weeks of age and were more (P < 0.05) fearful of humans, as indicated by less approach to a stationary human, at 14 weeks of age than gilts in the pleasant and minimal handling treatments. It was concluded that the unpleasant and inconsistent handling treatments resulted in a chronic stress response with consequent adverse effects on growth performance. The implications of these results for the reproductive performance and welfare status of breeding pigs are discussed.

A study of the relationships between the attitudinal and behavioural profiles of stockpersons and the level of fear of humans and reproductive performance of commercial pigs

This study examined the relationships between the attitude of the stockperson, the behaviour of the stockperson, the level of fear of humans by sows and reproductive performance at 19 commercial farms. The attitude of the stockperson was measured with respect to the stockpersons opinion of the pigs behaviour and how the stockperson evaluated his own behaviour, and the observations on the stockpersons behaviour concentrated on the nature of the physical interactions directed towards pigs. The level of fear of humans by sows was assessed by observing their approach behaviour to an experimenter in a standard 3-min test. Some of the variables of the stockpersons attitude and behaviour were significant predictors of the level of fear of humans by sows. For example, the attitude of the stockperson towards petting pigs and the proportion of physical interactions by the stockperson that were negative (aversive) in nature were significantly (P<0.01) related to the time taken for sows to physically interact with the experimenter in the standard 3-min test. The level of fear of humans was highly associated with the reproductive performance of the sow. The time taken to enter an area within 0.5 m of the experimenter in the standard 3-min test was significantly (P<0.01) related to the farrowing rate of the sows. As a result of these relationships, it is not surprising that some of the variables of the stockpersons attitude and behaviour were good predictors of reproductive performance. For example, the attitude to the use of verbal effort in moving pigs and the number of physical interactions of an intence negative nature were both highly (P<0.01) related to the total litter size. These relationships demonstrate that there may be substantial potential to reduce the level of fear of humans by commercial sows, in order to improve reproductive performance, by employing stockpersons that have desirable attitudinal and behavioural profiles.

A chemical analysis of samples of crude glycerol from the production of biodiesel in Australia, and the effects of feeding crude glycerol to growing-finishing pigs on performance, plasma metabolites and meat quality at slaughter

Theaimsofthisstudywereto:(i)determinethechemicalcompositionof11samplesofcrudeglycerolcollected from seven Australian biodiesel manufacturers; and (ii) examine the effects of increasing levels of crude glycerol fed to growing-finishing pigs on performance, plasma metabolites and meat quality at slaughter. Chemical composition of crude glycerol samples varied considerably; glycerol content ranged between 38 and 96%, with some samples containing up to 29% ash and 14% methanol. One of these samples (76.1% glycerol, 1.83% methanol) was then fed to 64 female pigs (50.95.55kg;means.d.)allocatedtooneof fivedietarytreatments(0,4,8,12and16%crudeglycerol)untiltheyreached 105 kg liveweight. There were no statistical differences in performance indices with increasing levels of added glycerol, althoughtherewasanunexpectedlyhighvariationbetweentreatments.Bloodglycerollevelswereunaffectedbydietinweek two of the experiment, but increased linearly (P 0.05).Dietscontainingaddedcrude glycerolwerelessdustyaftermixing,butdietsthatcontained8,12and16%glycerolallformeda firmaggregatewithin24hof mixing that presented some feeding difficulties. This might restrict inclusion of glycerol in mash diets to dietary levels less than8%.Furthermore,levelsofresiduessuchasmethanolandashshouldbemonitoredtopreventexcessiveamountsofthese compounds in pig diets.

Feeding a diet with decreased protein content reduces indices of protein fermentation and the incidence of postweaning diarrhea in weaned pigs challenged with an enterotoxigenic strain of Escherichia coli

This study evaluated the effect of feeding low protein (LP) diets for 7 or 14 d after weaning or a high protein (HP) diet for 14 d after weaning on postweaning diarrhea (PWD), indices of protein fermentation, and production in pigs infected or not infected per os with an enterotoxigenic strain of Escherichia coli. A total of 72 female pigs weaned at aged 21 d with initial BW of 5.9 +/- 0.12 kg were used in a 3 x 2 factorial arrangement of treatments. The factors were 3 feeding regimens associated with different combinations of feeding duration and diet CP level: (i) HP diet (256 g of CP/kg) fed for 14 d after weaning, (ii) LP diet (175 g of CP/kg) fed for 7 d after weaning, and (iii) LP diet fed for 14 d after weaning; and infection or noninfection with an enterotoxigenic strain of E. coli (10(7) cfu/mL, serotype O149:K91:K88) at 72, 96, and 120 h after weaning. The LP diets were fortified with crystalline Ile and Val to achieve an ideal AA pattern. A second-stage diet (213 g of CP/kg) was fed to pigs at the conclusion of each feeding regimen, and the study finished 4 wk after weaning. None of the diets contained antimicrobials. Feeding the LP diets decreased (P < 0.001) plasma urea nitrogen, fecal ammonia nitrogen concentrations, and the incidence of PWD, but increased (P = 0.001) fecal DM content compared with pigs fed HP in the 2-wk period after weaning. Infection increased shedding of beta-hemolytic E. coli (P < 0.001), the incidence of PWD (P < 0.001), and fecal ammonia nitrogen concentrations (P < 0.01), but did not interact with feeding regimen, after weaning. Pigs challenged with E. coli grew more slowly (P < 0.001) and had decreased G:F (P < 0.01) compared with nonchallenged pigs in the 4-wk period after weaning. Feeding an LP diet for 7 or 14 d after weaning markedly reduced the incidence of PWD after infection with beta-hemolytic E. coli. Infection was associated with decreased indices of protein fermentation in the distal gastrointestinal tract but did not compromise the growth of weaner pigs in the 4-wk period after weaning.

The effects of handling by humans at calving and during milking on the behaviour and milk cortisol concentrations of primiparous dairy cows

This study examined the effects of human presence at the time of calving of primiparous cows, and the behaviour of the stockperson during milking on the behaviour of the cows during milking and in response to an experimenter in a standard 5-min test (human test). Cows which were not handled around the time of their first calving (n=7) displayed a higher (P<0.05) number of flinch, step and kick (FSK) responses during the first 20 weeks of lactation than cows which were handled (n=7); most of these FSK responses occurred in the close presence of the stockperson. It is of interest that although the two treatments did not differ in the amount of extra assistance given by the stockperson, the number of FSK responses of cows was strongly (P<0.01) and positively correlated with the amount of extra assistance given by the stockperson in the form of attaching a kick-bar, replacing dislodged cups or steadying the cow by holding the tail or leg. Cows in the no handling treatment were also slower (P<0.05) to enter areas within 1 and 2 m of the experimenter in the human test conducted in the sixth week of lactation and had higher (P<0.05) mean cortisol concentrations in their milk than cows in the handling treatment. It is proposed that the lower FSK response of cows that received human contact at the time of their calving was a result of these cows being less fearful of humans. Although the two stockpersons differed significantly (P<0.01) in the proportion of physical interactions which were negative (aversive) in nature that they directed towards cows, the stockpersons had no significant influence on the behaviour of the cows during milking. However, the number of physical interactions that the cow received that were of a positive nature was significantly (P<0.05) correlated with the total number of FSK responses displayed in the first 2 weeks of lactation. It appears that stockpersons recognize those cows with a high FSK response and attempt to quieten them with the use of interactions that are positive in nature.

Effects of social environment on welfare status and sexual behaviour of female pigs. II. Effects of space allowance

Abstract This study examined the effects of housing groups of adult female pigs (6 pigs per group) with a space allowance of 1, 2 or 3 m2 per pig on sexual behaviour and welface status, determined by plasma free-corticosteroid concentrations. A lower percentage of gilts was detected in oestrus and a lower percentage of gilts was mated when housed with a space allowance of 1 m2 per gilt than with a space allowance of either 2 or 3 m2 per gilt (oestrus detection rate of 79, 88 and 100%, respectively, and a mating rate of 77, 85 and 97%, respectively). There was a significant increase in plasma free-corticosteroid concentrations when gilts were housed with a space allowance of 1 m2 per gilt. The elevated free corticosteroid levels of gilts in the 1 m2 per gilt treatment suggests that a chronic stress response due to crowding may have been responsible for the apparent impairment in the sexual behaviour of these animals.

Effects of feeding low protein diets to piglets on plasma urea nitrogen, faecal ammonia nitrogen, the incidence of diarrhoea and performance after weaning

This study evaluated the effects of feeding pigs low protein (LP) diets for different lengths of time after weaning on indices of protein fermentation, the incidence of post-weaning diarrhoea (PWD), growth performance, and total-tract apparent digestibility. Sixty weaner pigs weighing 6.1 ± 0.13 kg (mean ± SEM) were used in a completely randomised design having five treatments: (i) a high protein diet (HP, 243 g/kg CP) fed for 14 d after weaning (HP14); (ii) a low protein diet (LP, 173 g CP/kg) fed for 5 d after weaning (LP5); (iii) LP diet fed for 7 d after weaning (LP7); (iv) LP diet fed for 10 d after weaning (LP10), and (v) LP diet fed for 14 d after weaning (LP14). All diets were supplemented with lysine, methionine, tryptophan and threonine, with all LP diets additionally fortified with crystalline isoleucine and valine to conform to a proposed ideal amino acid (AA) pattern. A second-stage diet (215 g CP/kg) was fed to pigs at the conclusion of each treatment. None of the diets contained antimicrobial compounds. Feeding a LP diet, regardless of duration of feeding, decreased plasma urea nitrogen (p < 0.001) and faecal ammonia-nitrogen (p < 0.001) contents. Feeding a LP diet, irrespective of feeding duration, decreased the incidence of PWD at day 8 after weaning (p = 0.044), and pigs fed diets LP7, LP10 and LP14 had firmer faeces (p = 0.030, p = 0.047 and p = 0.007, respectively) between days 10 and 12 after weaning. Treatments LP5, LP7, LP10 and LP14 did not reduce (p > 0.05) growth performance up to 106 days after weaning compared to pigs fed the HP diet. Total-tract apparent digestibility of dry matter, energy and crude protein were similar (p > 0.05) between treatments. Our data suggest that feeding a LP diet, supplemented with AA to conform to an ideal AA pattern, for 7–10 days after weaning can reduce PWD in pigs fed antibiotic-free diets without compromising production.

The influence of early contact with humans on subsequent behavioural response of pigs to humans

This study examined the influence of three handling treatments, imposed from birth to 8 weeks, on the approach behaviour of 24 pigs to humans at 10–24 weeks of age. Piglets in two treatments, weaning/handling and handling, regularly received human contact, while piglets in the third treatment, no handling, only received human contact during routine husbandry. Piglets in the weaning/handling treatment were artificially reared, while those in the other two treatments remained on the sow until weaning at 4 weeks of age. Pigs in the weaning/handling and handling treatments showed increased approach to a stationary human in six tests from 10 to 24 weeks of age. For example, piglets in the weaning/handling and handling treatments spent more (P<0.01) time within 0.5 m of the human and were quicker (P<0.05) to physically interact with the human than pigs in the no handling treatment. Observations on the sexual behaviour of the boars from 25 to 35 weeks of age indicated that handling had no adverse effects on sexual behaviour. It is concluded that early handling of pigs will influence their behavioural response to humans later in life. Therefore, early handling may be a practical method for man to manipulate the pigs subsequent relationship with humans. The possibility of the existence of a “sensitive period” for “socialization” in pigs is discussed in the light of the present results.

Reducing the length of time between slaughter and the secondary gonadotropin-releasing factor immunization improves growth performance and clears boar taint compounds in male finishing pigs.

The objective of this study was to evaluate whether altering the timing of the secondary anti-gonadotropin-releasing factor (GnRF) immunization closer to slaughter in male finishing pigs would reduce the increase in P2 fat depth (6.5 cm from the midline over the last rib), while still limiting the incidence of boar taint. Entire male pigs are immunized against GnRF to reduce the concentration of testicular steroids that in turn limits the incidence of boar taint. Additionally, testicle measurements and color measurements were taken to examine whether they could be used to differentiate nonimmunized entire males from immunized male pigs. A total of 175 Large White × Landrace entire male pigs aged 16 wk (59 kg of BW) were used in a completely randomized design with 5 treatment groups based on the time that pigs received the secondary immunization before slaughter. Pigs were housed in groups of 7 and randomly allocated to 1 of 5 treatments with 5 replicates per treatment. The treatment groups were as follows: no secondary immunization before slaughter, and the secondary immunization given at 2, 3, 4, or 6 wk before slaughter. The P2 fat depth levels were reduced (P = 0.054) with the secondary immunization closer to slaughter (11.7, 11.3, 12.8, 12.6, and 13.7 mm for no secondary immunization, secondary immunization at 2, 3, 4, and 6 wk before slaughter, respectively). Androstenone concentration did not exceed the generally accepted industry sensory threshold of 1.0 µg/g of fat, and both androstenone concentration in the adipose tissue and testosterone concentrations in the blood were suppressed (P < 0.001) in all immunized pigs regardless of timing of the secondary immunization compared with pigs that did not receive the secondary immunization. Skatole concentration of all pigs in the experiment did not exceed the generally accepted industry sensory threshold of 0.2 µg/g. Testes weight was reduced (P < 0.001) with increased time between slaughter and the secondary immunization. Immunized pigs, regardless of time before slaughter, had greater L* (lightness) and b* (yellowness) color of the testicle surface (P < 0.001 and P = 0.020, respectively), and less a* (redness) color compared with entire males (P < 0.001). The study provides further evidence of the efficacy of the anti-GnRF immunization and indicates that the secondary immunization can be moved closer to slaughter, while still limiting the incidence of boar taint. Testicle measurements and color measurements together could provide a method of discrimination between carcasses from immunized entire males clear of boar taint and tainted carcasses.