Behavior and handling of physically- and immunologically-castrated market pigs at home and going to market Kimberly Guay, Guilherme Salgado, Garrett Thompson, Brittany Davis, Avi Sapkota, Wirawat Chaya, and John J McGlone. Pork Industry Institute, Texas Tech University, Lubbock, TX. Abstract Physical castration is a common management practice on commercial pork farms in the USA. Castration is performed primarily to reduce the rate of boar taint (an offensive odor in the meat of intact male post-pubertal males) and aggressive behavior. One alternative to physical castration (PC) is to immunologically castrate (IC) male pigs by blocking gonadotropin releasing factor (GnRF) thus, reducing levels of LH, FSH, Testosterone and Androstenone and Skatole. The objectives of this study were to evaluate the effects of immunological castration on pig behavior, human-pig interactions, and handling during and after transport. Behaviors of PC barrows and IC barrows were sampled at three time points after entering finishing at 9 wk of age: 7 wk (prior to first injection), and 16 wk (after immunization was complete) into finishing and one day before marketing (16 to 19 wk into finishing). Handling during loading and unloading of trailers going to market were also quantified. Prior to the first injection, intact males showed increased aggression (P = 0.014) and mounting (P = 0.048) while the PC barrows spent more time feeding (P = 0.003) than boars. The treatment by time interaction were significant for lying (P = 0.018), aggression (P = ) and standing (P = 0.009) behaviors. Few differences were observed in pig-human interactions between PC barrows and IC barrows. IC approached people in the same amount of time as PC barrows, but were more aggressive in their chewing and rubbing on the test person’s pant leg and boots. When handling and loading for processing in the home barn, PC barrows are more vocal than IC barrows (P < 0.05). Fewer dead and down pigs were observed among IC (zero) compared with PC barrows (1.17%). Immunological castration may result in similar or improved animal welfare compared to physical castration without pain relief. Materials and Methods Pigs were in two adjacent barns containing 48 pens per barn initially stocked with 2,304 pigs. The experimental animals were domestic swine on a commercial farm. Pigs were a cross of widely used commercial lines, high-performance animals of modern genetics. All pigs were born the same week from a common set of sow barns, and then transferred to a nursery for approximately 7 wk, then moved to the test grow-finish barns in pens of 24 pigs each. This study was divided into three phases. Phase 1: pre-immunization period (week 6 in grow-finish; prior to the first immunization). One half of male piglets had been physically castrated on day 3 of life. These animals were called PC barrows. The other half of male piglets were not castrated at processing and remained as intact males during this phase; Phase 2: post-immunization period (week 16 in grow-finish). After the first and second Improvest™ injections at weeks 11, 13, or 14 of finish phase, and Phase 3: Four to eight weeks after the second dose “final marketing week” with 19 weeks of finishing. Observers used a scan sampling method to record behavior in each pen every 12 min for 24 h. A modified fear test, modified from that described by Gonyou and Stricklin 5 was used to assess pig fear. Handling during loading and unloading of trailers going to market were also quantified. Data were converted to a percentage of pigs expressing each behavior over time. Data were summarized by hour over the 24 h observation period. Data were then converted to percentages of time each hour that pigs expressed each behavior. Prior to analysis, percentage data were subjected to square root-arcsine transformation. Statistical Analysis Systems (SAS) General Linear Models (GLM) were used for all analyses. Results and discussion Percentage of time each pig was recorded showing a specific behavior throughout the study (Phases 1-3) is shown in Table 1. Prior to the first injection, intact males showed increased aggression (P = 0.014) and mounting (P = 0.048) while the PC barrows spent more time feeding (P = 0.003) than boars. The treatment by time interaction were significant for lying (P = 0.001), aggression (P = ) and standing (P = 0.009) behaviors. Few differences were observed in pig-human interactions between PC barrows and IC barrows. IC approached people in the same amount of time as PC barrows, but were more aggressive in their chewing and rubbing on the test person’s pant leg and boots. When handling and loading for processing in the home barn, PC barrows are more vocal than IC barrows (P < 0.05). Fewer dead and down pigs were observed among IC (zero) compared with PC barrows (1.17%). Immunological castration may result in similar or improved animal welfare compared to physical castration without pain relief. Introduction. Physical castration (PC) is a common management practice on commercial pork farms in the USA. Castration is performed primarily to reduce the rate of boar taint, aggressive behavior in post-pubertal male pigs and undesirable pregnancy at slaughter. Androstenone and related steroids along with skatole are responsible for the boar taint that is often offensive to pork consumers. Skatole is a byproduct of the bacterial metabolism of the amino acid tryptophan in the large intestine. Skatole is deposited in the adipose tissue of the pig (Lundstrom and Zamaratskaia, 2006). The industry favors marketing pigs at body weights well past the onset of puberty. Therefore, to prevent boar taint, male piglets are typically physically castrated at less than 5 d of age. Several consequences of physical castration include a negative effect on the welfare of the animals, as it causes pain and distress (McGlone and Hellman, 1988; Prunier et al., 2005; Sutherland et al., 2010, Van Beirendonck et al., 2011) which can lead to higher mortality and morbidity rates. Attempts to reduce the pain and distress by use of common local or general anesthetics were unsuccessful to date (McGlone et al., 1993; Sutherland et al., 2010; Rault and Lay, 2011). One alternative to physical castration is to immunologically castrate (IC) male pigs. Immunological castration yields a carcass without boar taint and may improve pig welfare by reducing the stress of physical castration (Bonneau et al., 1994; Dunshea et al., 2001; Metz et al., 2002; Turkstra et al., 2002; Jaros et al., 2005). One method of immunological castration blocks the activity of GnRF, reducing levels of LH, FSH and testosterone and androstenone and skatole. Furthermore, because pigs can be immunologically castrated later in life, compared to physical castration, the increased lean growth and improved feed efficiency of the boar can be maintained further into finishing (Dunshea et al.; 2001; DeRoest et al., 2009; Schmidt et al. 2011). Zamaratskaia et al. (2008) found that levels of testosterone and skatole were decreased after the second immunization with a GnRF conjugate. Immunological castration changes the behavior of male pigs (Baumgartner et al. 2010; Fabrega et al. 2010; Pauly et al. 2009). The safety of people who handle male pigs at the farm and at the plant has not been assessed. Will the immunologically castrated pigs act more like barrows or boars in their aggressive and feeding behaviors? Cronin et al. (2003) found that IC barrows spent more time at feeders and spent less time displaying sexual and aggressive behavior than the boars. Cronin et al., (2003) also reported that before the second immunization (at 17 wk of age) the IC barrows showed similar aggressive behaviors as boars and higher than PC barrows. The objectives of this study were to evaluate the effects of immunological castration on behaviors such as, human-pig interactions, aggressiveness, feeding, social, mounting, and lying behaviors; as well as evaluating their behavior during loading and unloading of pigs going to market. Conclusion Castration of pigs largely eliminates boar taint in commercial pigs. At the same time, it causes acute and prolonged pain and performance changes including increased marbling and worse feed efficiency. Immunological castration as an alternative to physical castration may eliminate the pain of castration while capturing some performance advantages. Prior to immunization, intact male pigs showed a small but significant increase in aggression and mounting of each other, but did not differ in pig-human interactions, compared with barrows. Closer to harvest and after the second immunization, PC barrows and IC barrows showed similar levels of behavior. IC barrows were more interactive with people in their pen. Immunologically castrated pigs vocalized less and had fewer dead and down pigs than contemporary barrows. Handling going on the livestock trailers and handling coming off the trailers showed no issues with pig handling or pig-human interactions. Behavioral or handling issues were not identified among IC barrows compared with PC barrows. At the processing plant, the rate of dead and down pigs fell to zero among immunologically castrated males while conventional barrows had about 1% dead and down pigs. Immunological castration may result in improved animal welfare compared with physical castration without pain relief, but a complete animal welfare assessment would include both improvements and detriments in pig welfare generated by any alternative to physical castration. Immunological castration is a viable alternative to physical castration that on the whole improves the welfare of male pigs.. References: 1. McGlone, J. J., R. I. Nicolson, and J. M. Hellman, and D. N. Herzog The development of pain in young pigs associated with castration and attempts to prevent castration-induced behavioral changes. J. Anim. SCi. 71: Sutherland, M. A., B. L. Davis, T. A. Brooks, and J. J. McGlone Physiology and behavior of pigs before and after castration: effects of two topical anesthetics. Animal. 4: Dunshea, F. R., C. Colantoni, K. Howard, P. Jackson, K. A. Long, S. Lopaticki, E. A. Nugent, J. A. Simons, J. Walker, and D. P. Hennessy Vaccination of entire boars with Improvac eliminates boar taint and increases growth performance. J. Anim. Sci. 79:2524– Metz C., K. Hohl, S. Waidelich, W. Drochner, and R. Claus Active immunization of boars against GnRH at an early age: consequesnces for testicular function, boar taint accumulation and N-retention. Livest. Prod. Sci. 74: Gonyou, H. W. and W. R. Stricklin Effects of floor area allowance and group size on the productivity of growing/finishing pigs. J. Anim. Sci. 76: Table 2. Main effects of barrow vs. intact males on pig behavior. These data were collected before immunization treatments were applied (Oct, 2011). Values are expressed as percentage time engaged in each behavior averaged over 24 hours. Analyses were on transformed data. Phase 1. Before injectionsP-values Behavior BarrowIntact maleSETreatment Treatment X Time Number pens*12 -- Feeding5.71%4.93% b Drinking0.54%0.50% Aggression0.09%0.21% <.0001 Mounting0.03%0.07% Social1.19%1.18% Standing6.63%6.80% Lying85.8%86.3% * Each pen contained 21, 23 or 24 animals. a,b Means within a row with different superscripts differ, P < Table 3. Pig-human interactions and percentage of pigs with hernias at observation six weeks into finishing (Oct. 2011). Phase 1. Barrows 12 pens Intact males 36 pens SEP-value Walking the Pens Number of pigs in contact Fear Test Time for a pig to come within 1 m of human, s Time for a pig to contact human, s Aggressiveness of pig-human interaction (scale 1 to 5 with 5 being aggressive) Mortality, % * Each pen contained 21, 23 or 24 animals. Table 4. Twenty-four hour observation of effects of barrow vs. intact males on pig behavior, after second injection (Jan 3, 2012). Percent time engaged in each behavior. Phase 2. Immunized, second injection P-values IC barrow BehaviorPC barrow 11wk injection 13wk injection 14wk injection SE Treatmen t *Time Number pens*24 -- Feeding4.69%4.79%4.96%4.75% Drinking0.57%0.66% 0.72% Aggression0.013%0.018%0.017%0.018% Mounting0.012%0.008%0.022%0.027% Social0.528%.353%0.427%0.400% Standing5.20%4.91%4.68%4.85% Lying85.5% a 86.4% a 85.1% b 86.3% a 0.928< Table 5. Pig-human interactions and mortality at observation. Fifteen weeks into finishing (Jan 3, 2012). Phase 2. Barrows IC barrows 11 wk 13 wk 14 wk SEP- values Number of pens*12 Fear Test Time for a pig to come within 1 m of human, s Time for a pig to contact human, s Aggressiveness of pig-human interaction (scale 1 to 5 with 5 being aggressive) 2.58 a 3.08 b 3.0 b Mortality % * Each pen contained 21, 23 or 24 animals. a,b Means within a row with different superscripts differ, P < Table 6. Handling data for pigs being loaded and unloaded – at 15 weeks into finishing (Jan 3, 2012). Phase 2. MeasureBarrow11 wk13 wk14 wk*SEP-value Number pens12 -- Vocalizations in home pen, number 16.1 a 8.2 b 5.8 b Time from scale to barn door, s Slips, falls and vocalizations* a,b Means within a row with different superscripts differ, P < A lower value means pigs were more fearful * The handling was excellent and zero slips, falls or vocalizations were recorded in the chute entering the livestock trailer. With no variation, statistical analyses are not appropriate. Pigs immunized at 14 weeks into the grow-finish phase were not marketed at this time. Table 7. Main effects of barrow vs. intact males on pig behavior, % after second injection (Jan 31, 2012) time engaged in each behavior, during treatment injections. Phase 2. P-values BehaviorBarrow 11wk injection 13 wk injection 14 wk injection SE Treatment *Time Number pens*12 -- Feeding7.34% 7.15%6.61% Drinking0.93%1.04%1.05%1.25% Aggression0.04% 0.03%0.13% Mounting0.07% 0.03%0.14% Social1.04%1.11%1.20%0.99% Standing5.04% a 3.95% a 5.40% a 4.53% b Lying a 85.5% a 86.4% a 85.1% a 86.3% b 0.009< * Each pen contained 21, 23 or 24 animals. Table 8. Number of Dead and Down pigs off of trailers arriving at processing plant. Phase 3. ItemPC barrowIC barrowBarrow/Gilts Number of trailers69 Number of pigs1,0111,454 Dead/killed on arrival0.50%0.00% NANI %0.00%0.21% NAI % 0.21% Total dead and down1.17%0.00%0.42% 1 Non-ambulatory, non-injured. 2 Non-ambulatory, injured.