Effect of environmental enrichment and group size on the water use and waste in grower-finisher pigs

Environmental enrichment in finishing pigs: does it promote any changes in bone biomechanics?

The resistance of pigs' bone structure was evaluated for the first time, reared with and without environmental enrichment (EE) in the finishing phase using techniques in bone biomechanics; 432 swine from the Hampshire breed, being males and females, with initial body weight between 22 and 27 kg and final body weight between 110 and 125 kg were evaluated for 112 days. The experimental design was in randomized blocks, with 6 treatments, distributed in a 2 × 3 factorial scheme (sex × conditions in creation), with 12 repetitions/treatment, totaling 72 pens. The treatments were as follows: branched chain for males (T1), sisal branched string for males (T2), males without EE (T3), branched chain for females (T4), sisal branched string for females (T5), and females without EE (T6). At the end of the experimental period, all animals were slaughtered in an industrial slaughterhouse, having their femur bones collected for bone biomechanics analysis. There was no effect (P > 0.05) of the interaction (enrichment × sex) and individual factors for bone weight. There was a tendency (P = 0.08) of the interaction for flexion force, being higher in males enriched with branched ropes and chains. For breaking stress, there was an interaction effect (P = 0.04), being the females without EE the ones showing the lowest breaking stress, favoring bone fragility. The use of branched ropes and chains strengthens the bone structure in swine in the termination phase (110-125 kg BW - 183-190 days in age), being an important strategy used to meet the animal welfare requirements.

Evaluation of environmental enrichment on productive and behavioral responses of finishing pigs

Productive and behavioral responses of finishing pigs with and without access to environmental enrichment (EE) were evaluated. A total of 432 pigs, male and female, Hampshire line, initial and final weight of 22-27 kg and 110-125 kg, respectively, were studied for 112 days. The study design was in random blocks, with 6 treatments, distributed in a factorial scheme 2 × 3 (sex × treatment) and 12 repetitions/treatment, totalling 72 pens. The animals were weighed and distributed in 3 blocks-light (20.3 to 24.8 kg), medium weight (24.8 to 27.7 kg), and heavy (27.7 to 33.8 kg). The treatments were as follows: branched chains for males (T1); branched sisal ropes for males (T2), males without EE (T3); branched chains for females (T4); branched sisal ropes for females (T5) and females without EA (T6). There was no effect (P > 0.05) of interaction (enrichment × sex) and sex on performance. Daily consumption and daily weight gain were lower (P < 0.05) in the chain group compared to the sisal rope and control groups. Feed conversion was similar (P > 0.05) between treatments under study. There was no interaction between gender and enrichment for behavioral responses (P = 0.8986). However, there was an environmental enrichment (P = 0.0017; P < 0.001) and gender (P = 0.0251; P < 0.001) effect in relation to the animals' behavior in the morning and in the afternoon, respectively. Calmer animals, regardless of sex, were observed for groups without enrichment (control) and morning and afternoon periods. The animals interacted with the types of enrichment under study, given the higher probabilities of interaction with the object for males and females in the morning and afternoon shifts. It was observed, regardless of the shifts, that the control treatment for males and females was different when compared to the other enrichments for males and females. In general, the pigs' behaviors were expressed more in the afternoon when compared to the morning. It was observed that the animal interaction and aggression (afternoon shift) behaviors are more related to the control group, while object interaction is more related to the enriched treatments. The use of sisal ropes and branched chains guarantees the performance and behavior of pigs in the finishing phase, but we recommend the use of branched chains, as this enrichment increased the profitability of the farmer by reducing feed consumption, maintaining feed conversion and animal welfare, besides being a more durable material than sisal rope.

Water use patterns within each day: Variation between batches of growing pigs in commercial production systems

Objective: To measure, describe, and compare the water use patterns within each day for multiple cohorts of weaner, grower, and finisher pigs in farm buildings. Materials and methods: Prospective, observational cohort studies of the water use patterns within each day were conducted in 5 pig buildings using either a turbine or ultrasonic water flow meter attached to the main water pipe entering each building. Water use data were collected from multiple batches of pigs (second-stage weaners over eleven 48-day periods and grower-finishers over 4 periods of 21-43 days). Semi-parametric models of pig water use patterns within each day were estimated using the brms software package in R. To estimate the interacting effects of time and pig body weight on water use by pigs, we used tensor product smooths for time and pig body weight. Results: The water use pattern within each day varied between the cohorts, and the pattern of many cohorts changed as the pigs gained weight. Some patterns were unimodal and others were bimodal, with the main peak in water use occurring early afternoon to late afternoon. Implications: Water use patterns of pigs within each day varied between and within cohorts. The water use pattern of one cohort cannot be used reliably to predict that of other cohorts, even if they are reared in the same building. Water use pattern data may be valuable for optimizing in-water antimicrobial dosing regimens.

Use of drinkers by finisher pigs depend on drinker location, pig age, time of day, stocking density and tail damage

Water is a vital nutrient for mammals, including the pig. Despite this, the use of drinkers and water have not yet been explicitly quantified across the finisher period. The current study aimed at gaining greater insight into finisher pigs' drinker use and its relation to drinker location, age, time of day, stocking density, enrichment provision and tail damage. The experiment included 110 pens of finisher pigs over a 9-week period, with two drinker cups per pen. Pens had a stocking density of either 0.73 m²/pig (n = 54 pens, 18 pigs per pen) or 1.21 m²/pig (n = 56 pens, 11 pigs per pen), were either provided with straw (n = 54, 150 g per pig and day) or not (n = 56), and had pigs with either undocked (n = 50) or docked tails (n = 60). Drinker use was recorded automatically by water-flow meters and summed to L and number of activations per hour and pig. Pens never experiencing a tail damage event (at least one pig in the pen with a bleeding tail) were used to investigate the normal drinker use of finisher pigs (n = 56). The water use of pigs increased from 3.7 to 8.2 L per pig and day during the 9 weeks, and this increase was mainly seen during the two large peaks of the diurnal pattern within the pigs' active period (06:00-18:00 h). No such increase was seen in the activation frequency at average 50 activations per pig and day. A decrease in stocking density increased both water use and activation frequency during the active period, suggesting that pigs at the standard space allowance and pig:drinker ratio could be restricted in their access to the drinking cups. The pigs also seemed to prefer to use the drinking cup closest to the feeder. Water use and activation frequency did not change the last 3 days prior to an event of tail damage, but general differences were seen between pens with and without a tail damage event. The current results may explain the success of previous studies in classifying tail damage pens from pens without tail damage using sensor data on drinker use.

Water consumption and wastage behaviour in pigs: implications for antimicrobial administration and stewardship

Daily water use and wastage patterns of pigs have major effects on the efficacy of in-water antimicrobial dosing events when conducted for metaphylaxis or to treat clinical disease. However, daily water use and wastage patterns of pigs are not routinely quantified on farms and are not well understood. We conducted a prospective, observational 27-day study of the daily water use and wastage patterns of a pen group of 15 finisher pigs reared in a farm building. We found that the group of pigs wasted a median of 36.5% of the water used per day. We developed models of the patterns of water used and wasted by pigs over each 24-h period using a Bayesian statistical method with the brm() function in the brms package. Both patterns were uni-modal, peaking at 1400-1700, and closely aligned. Wastage was slightly greater during hours of higher water use. We have shown that it is feasible to quantify the water use and wastage patterns of pigs in farm buildings using a system that records and aggregates data, and analyses them using hierarchical generalised additive models. This system could support more efficacious in-water antimicrobial dosing on farms, and better antimicrobial stewardship, by helping to reduce the quantities of antimicrobials used and disseminated into the environment.

Risk Factors for Chronic Stress in Sows Housed in Groups, and Associated Risks of Prenatal Stress in Their Offspring

Chronic stress has a detrimental effect on sow welfare and productivity, as well as on the welfare and resilience of their piglets, mediated prenatally. Despite this, the specific risk factors for chronic stress in pregnant sows are understudied. Group-housed pregnant sows continuously face numerous challenges associated with aspects of the physical (group type and size, flooring, feeding system) and social (stocking density, mixing strategy) environment. There are many well-known potent stressors for pigs that likely contribute to chronic, physiological stress, including overcrowding, hot temperatures, feed restriction, inability to forage, uncomfortable floors, and poor handling. Some of these stressors also contribute to the development of production diseases such as lameness, which in turn are also likely causes of chronic stress because of the associated pain and difficulty accessing resources. The aim of this review is to discuss potential risk factors for chronic stress in pregnant sows such as space allowance, group size and type (stable/dynamic), feeding level, lameness, pen design, feed system, enrichment and rooting material, floor type, the quality of stockmanship, environmental conditions, and individual sow factors. The mechanisms of action of both chronic and prenatal stress, as well as the effects of the latter on offspring are also discussed. Gaps in existing research and recommendations for future work are outlined.