Larry J. Sadler

The effect of selection for residual feed intake on general behavioral activity and the occurrence of lesions in Yorkshire gilts

The objectives of this study were to determine the effect of selection for improved residual feed intake on behavior, activity, and lesion scores in gilts in their home pen. A total of 192 gilts were used, 96 from a line that had been selected for decreased residual feed intake over 5 generations (LRFI) and 96 from a randomly bred control line. Gilts were housed in 12 pens (16 gilts/pen; 0.82 m(2)/gilt) containing 8 gilts from each line in a conventional grow-finish unit. Twelve hours of video footage were collected on the day of placement and then every 4 wk for 3 more observational periods. Video was scored using a 10-min instantaneous scan sampling technique for 4 postures (standing, lying, sitting, and locomotion) and 1 behavior (at drinker). Categories of active (standing, locomotion, and at drinker) and inactive (sitting and lying) were also created. Lesion scores were collected 24 h after behavior collection had begun. The body of a gilt was divided into 4 regions, with each region receiving a score of 0 (0 lesions) to 3 (5+ lesions). All statistical analyses used Proc Mixed of SAS. Data were analyzed separately for the day of placement and the subsequent 3 rounds. General activity was summarized on a percentage basis by each posture and behavior and subjected to an arcsine square root transformation to normalize data and stabilize variance. Analysis was performed on each behavior and posture. Lesion scores for each region of the body were analyzed as repeated measures. There were no differences (P > 0.05) between genetic lines for all postures and the behavior at drinker on the day of placement. However, over subsequent rounds it was observed that LRFI gilts spent less (P = 0.03) time standing, more time sitting (P = 0.05), and were less active (P = 0.03) overall. Gilts from the LRFI line had decreased (P < 0.045) lesion scores on the day after placement. However, over subsequent rounds there were no (P > 0.05) differences between the genetic lines. In conclusion, on the day of placement there were no postural, behavior, or general activity differences between genetic lines, but LRFI gilts had decreased lesion scores. Behavioral differences were observed between genetic lines over subsequent rounds, with LRFI gilts becoming less active, but there were no differences in lesion scores.

2011 and 2012 Early Careers Achievement Awards: farm and pig factors affecting welfare during the marketing process.

The objective of this paper is to review the scientific literature to identify on-farm factors that contribute to market weight pig transportation losses. Transportation of market weight pigs is an essential element to the multisite pork production model used in the United States. In 2011 alone, approximately 111 million market weight pigs were transported from the finishing site to the abattoir. For pigs, the marketing process can present a combination of potentially novel, physical, and/or unfamiliar experiences that can be stressful. If the pig cannot cope with these sequential and additive stressors, then an increased rate of transportation losses could occur with a detrimental effect on pork carcass value. Current yearly estimates for transport losses are 1 million pigs (1%). A variety of market weight pig and farm factors have been reported to detrimentally affect transportation losses. By understanding how pigs interact with their environment during marketing, researchers, producers, and personnel at the abattoir may begin to identify, prioritize, and attempt to minimize or eliminate these stressors. This process will ultimately decrease transportation losses, improve pork quality, and increase profitability.

Drinking behavior in nursery pigs: Determining the accuracy between an automatic water meter versus human observers

Assimilating accurate behavioral events over a long period can be labor-intensive and relatively expensive. If an automatic device could accurately record the duration and frequency for a given behavioral event, it would be a valuable alternative to the traditional use of human observers for behavioral studies. Therefore, the objective of this study was to determine the accuracy in the time spent at the waterer and the number of visits to the waterer by individually housed nursery pigs between human observers scoring video files using Observer software (OBS) and an automatic water meter Hobo (WM, control) affixed onto the waterline. Eleven PIC USA genotype gilts (22 +/- 2 d of age; 6.5 +/- 1.4 kg of BW) were housed individually in pens with ad libitum access to a corn-based starter ration and one nipple waterer. Behavior was collected on d 0 (day of weaning), 7, and 14 of the trial using 1 color camera positioned over 4 attached pens and a RECO-204 DVR at 1 frame per second. For the OBS method, 2 experienced observers recorded drinking behavior from the video files, which was defined as when the gilt placed her mouth over the nipple waterer. Data were analyzed using nonparametric methods and the general linear model and regression procedures in SAS. The experimental unit was the individual pen housing 1 gilt. The GLM model included the method of observation (WM vs. OBS) and time (24 h) as variables, and the gilt nested within method was used as the error term. Gilts consumed more water (P = 0.04) on d 14 than on d 0. The time of day affected (P < 0.001) the number of visits and the time spent at the waterer regardless of the method. However, the OBS method underestimated (P < 0.001) the number of visits to the waterer (3.48 +/- 0.33 visits/h for OBS vs. 4.94 +/- 0.33 for WM) and overestimated (P < 0.001) the time spent at the waterer (22.6 +/- 1.46 s/h for OBS vs. 13.9 +/- 1.43 for WM) compared with WM. The relationship between the 2 methods for prediction of time spent at the waterer and number of visits made by the gilts was weak (R(2) = 0.56 and 0.69, respectively). Collectively, these data indicate that the use of the traditional OBS method for quantifying drinking behavior in pigs can be misleading. Quantifying drinking behavior and perhaps other behavioral events via the OBS method must be more accurately validated.

Effects of flow rate and gas mixture on the welfare of weaned and neonate pigs during gas euthanasia

The objectives of this study were to assess efficacy and welfare implications of gas euthanasia when applied to weaned and neonate pigs. Parameters associated with welfare, which were measured before loss of consciousness, included open-mouth breathing, ataxia, righting response, and escape attempts. Two age groups (weaned and neonate) were assessed in 9 gas treatments arranged in a 2 × 4 factorial design, with 2 gas types (CO2 = 100% CO2 and 50:50 = 50:50 CO2:argon) and 4 flow rates (box volume exchange/min: slow = 20%; medium = 35%; fast = 50%; prefill = prefilled followed by 20%) and a control treatment in which ambient air was passed through the box. Pig pairs (10/treatment) were placed in a modified Euthanex AgPro system (Euthanex Corp., Palmer, PA). Behavioral and physiological responses were observed directly and from video recordings for latency, duration, prevalence (percent of pigs affected), and frequency (number of occurrences/pig). Data were analyzed as linear mixed models or with a Cox proportional hazard model as appropriate. Piglet pair was the experimental unit. For the weaned pig, welfare was superior with CO2 relative to 50:50 within 1 or more flow rates on the basis of reduced duration of open-mouth breathing, duration of ataxia, frequency of escape attempts, and duration and frequency of righting response (P < 0.05). No measured parameters indicated superior welfare with the use of 50:50, whereas latencies to loss of posture and last movement favored CO2 (P < 0.05). Faster flow rates were associated with reduced (P < 0.05) duration or frequency of open-mouth breathing, ataxia, and righting response, as well as superior (P < 0.05) indicators of efficacy, including latencies to loss of posture, gasping, and last movement, relative to slower flow rates. Weaned pigs were more likely to defecate (P < 0.01), display nasal discharge (P < 0.05), and display longer (P < 0.001) latencies to loss of posture and last movement than neonates. Duration of ataxia was the only parameter for which neonates were superior (P < 0.01) to weaned pigs during euthanasia. As such, a 50:50 CO2:argon gas mixture and slower flow rates should be avoided when euthanizing weaned or neonate pigs with gas methods. Neonate pigs succumb to the effects of gas euthanasia quicker than weaned pigs and display fewer signs of distress.

Risky behaviors performed by the piglet 72 hours after parturition that can contribute to pre-weaning mortality when housed in farrowing huts

Abstract The objective was to compare the behavior of loose-housed outdoor litters that had one or more piglet mortalities (CR; n=4) compared to litters where no mortalities occurred (NC; n=4). The litter of piglets was observed using 10-min scan samples over 72 h from birth and individual piglets were continually observed 1 h prior to death. Postures, nursing, unknown, location within the hut, and vicinity to the sow were determined. There were no differences observed for any measures 1 h before a piglets death. There were no differences for treatment or day by treatment over the 72 h for behaviors or vicinity to sow. There was a day effect with piglets becoming more inactive and nursing less often from d1 to d3. There was a day effect for vicinity to sow with piglets spending less time by the sow over the 3 d. Few behavioral differences were observed between treatments.

Are severely depressed suckling pigs resistant to gas euthanasia

Severely depressed pigs exhibit differences in a number of important parameters that may affect gas euthanasia, including decreased respiration rate and tidal volume. Hence, the objectives of this study were to assess the efficacy and animal welfare implications of gas euthanasia of suckling pigs with varied disease severity (severely depressed [DP] vs other [OT]). A 2 × 2 factorial design was utilised with two gas types (carbon dioxide [CO2]; argon [Ar]) and two flow rates (G = gradual, 35% box volume exchange per min [BVE min]; P = prefill + 20% BVE min). Sixty-two pigs were enrolled and tested as DP/OT pairs in each gas treatment combination. Pigs identified for euthanasia were assigned a subjective depression score (0 = normal to 3 = severely depressed). Pigs scored 3 and ≤ 1 were categorised as DP and OT, respectively. Significantly lower respiration, rectal temperature, pulse and weight were observed for the DP pigs relative to OT. Pigs were assessed for behavioural indicators of efficacy and welfare. No differences were observed between DP and OT when using P-CO2 or G-CO2. However in P-Ar, DP had greater latency to loss of consciousness relative to OT (212 [± 22] vs 77 [± 22] s), decreased latency to last limb movement (511 [± 72] vs 816 [± 72] s), greater duration of open-mouth breathing (151 [± 21] vs 69 [± 21] s), decreased duration ataxia (101 [± 42] vs 188 [± 42] s) and decreased righting response (27 [± 11] vs 63 [± 11] s). The G-Ar treatment was removed due to ethical concerns associated with prolonged induction. In conclusion, depression score did not affect pig responses to euthanasia with CO2 gas, but did affect responses to Ar. Furthermore, Ar was associated with a prolonged euthanasia process, including frequencies and durations of distress behaviours.

Influence of corn co-products on the behavioral repertoire of growing-finishing swine

Abstract The objective was to evaluate the pigs’ behavior when dietary hemicellulose content increased over the growing-finishing phase. Forty-eight crossbred barrows were allocated to eight chambers (n=2/treatment). Four diets were compared; Corn Germ Meal, Distillers Dried Grains with Solubles, Dehulled Degermed Corn and Corn. Behavior was recorded over six days when diets changed. Two behaviors (time spent at feeder and time spent at drinker) and two postures (active and inactive) were recorded. There was no treatment or treatment by time effects for any behaviors. Regardless of treatment, pigs spent more time at the feeder; 0700 and between 1600 and 1700. Time spent at the drinker peaked at 1400 and 1600. Pigs were most active at 0600 and then 0700–0900, 1300–1700 and 0500. Inclusion of hemicellulose content in the diet resulted in no changes to the pigs’ behavioral repertoire and they adapted quickly to all of the diets in this study.

The effect of selection for residual feed intake on scale-activity and scale-exit scores in Yorkshire gilts

The objectives of the present study were to use scale-activity and scale-exit scores to (1) determine the extent to which selection for improved residual feed intake (RFI) correlates with individual gilt temperament, (2) determine whether the timing of assessment affects the scores, and (3) determine whether gilts habituate to the process of weighing. To achieve these objectives, 192 grow–finish purebred Yorkshire gilts (39.7 ± 5.7 kg; 98 ± 6 days old) were utilised. Ninety-six gilts were from the 5th generation of a line selected for low residual feed intake (LRFI), and 96 gilts were from the 5th generation of a randomly selected control line (CRFI). Gilt activity and exit behaviour were scored on the weigh scale. The activity score was taken at two time points, namely, t = 0 (immediately on the back gate closing on the weight scale) and t = 15 (15 s later). Activity was assessed using a 5-point scoring system (1 = calm, minimal movement; 5 = continuous rapid movement and an escape attempt), and exit score was assessed using a 3-point scoring system (1 = no encouragement needed, full exit; 3 = encouragement needed). Gilts were weighed once every 2 weeks (each weighing considered a testing round) for a maximum of eight scores per gilt. Statistical differences were identified in all rounds for activity between genetic lines, except Rounds 2, 4 and 5. For both lines, gilt-activity scores decreased over rounds. The LRFI line began with a lower activity score (2.31 vs 2.65 ± 0.13), but did not experience as great of a drop in average score over rounds as did the CRFI gilts (0.62 vs 1.21). By the end of the trial, the CRFI gilts scored lower than the LRFI gilts. Activity was greater at t = 15 than at t = 0. Although timing affected the score, the pattern was similar, and so consistency will be more important than timing procedure. For exit scores, in Rounds 5 and 7, the LRFI line scored lower than the CRFI line, and there was a trend for the LRFI line to score lower in Round 6. Across all gilts, the mean exit score increased slowly throughout the trial. In conclusion, selection for lower RFI in purebred Yorkshires has an effect on activity score but this relationship is complex and warrants further research. The observation that gilts become habituated to the process of weighing supports the conclusion that the process is not aversive.

The Effect of Selection for Residual Feed Intake on Scale Activity in Yorkshire Gilts

and Implications The objective of this study was to determine the effect of selection for reduced feed intake (RFI) on scale activity for Yorkshire gilts. A total of 192 Yorkshire gilts were used, 96 were from a line that had been selected for low residual feed intake over 5 generations (LRFI) and 96 from a randomly bred control line (CRFI). Gilts were housed in 12 pens (16 gilts/pen; 0.82 m 2 /gilt) containing 8 gilts from each line in a conventional grow-finish unit. Gilts were weighed every 2-wks for a maximum of eight scores per gilt. Gilts were scored while on the weigh scale for activity using a whole number scale of one to five (1 = calm, minimal movement; 5 = continuous rapid movement and an escape attempt). Analyses were done using Proc Mixed of SAS. The LRFI line began with a lower scale activity score, but did not experience as great of a drop in their score as the CRFI gilts. The CRFI gilts scored lower by the end of the rounds compared to the LRFI gilts. In conclusion, selection for lower residual feed intake in purebred Yorkshires has a related effect on scale activity score but this relationship is complicated and thus warrants further research. Therefore, scale activity may not be an easy measure to be added to the list of already described traits in pigs as a factor which relates to selection for lower RFI.

The Effect of Selection for Residual Feed Intake on Lesion Scoresin Yorkshire Gilts

and Implications The objectives of this study were to determine the effect of selection for reduced residual feed intake (RFI) on lesion scores in gilts in their home pen. A total of 192 gilts were used; 96 were from a line that had been selected for low residual feed intake over 5 generations (LRFI) and 96 from a randomly bred control line (CRFI). Gilts were housed in 12 pens (16 gilts/pen; 0.82 m/gilt) containing 8 gilts from each line in a conventional grow-finish unit. Lesion scores were collected the day after placement and every 4 weeks for 3 subsequent periods. The gilt’s body was divided into 4 regions, with each region receiving a score of 0 (0 lesions) to 3 (5+ lesions). All analyses were done using Proc Mixed of SAS. The data were analyzed separately for the day after placement and the subsequent three rounds. Lesion scores for each region of the body were analyzed as repeated measures. Gilts from the LRFI line had lower (P 0.05) differences between the genetic lines. In conclusion, gilts from the line selected for low RFI had lower lesions scores on the day after placement into the grow-finish environment and this may be a useful tool to use in a selection program for more efficient gilts.