Implications of Lairage and Environmental Enrichment on Behavioral Responses and Skin Lesions in Finishing Pigs in a Slaughterhouse.

Different resources, such as environmental enrichment, are being evaluated in order to minimize animal stress and promote better conditions during the life cycle of animals, as consumers are increasingly concerned about animal welfare issues. Lairage represents an important stage in the swine production chain and is directly related to animal welfare. The aim of this study was to evaluate the effect of lairage time in the slaughterhouse and environmental enrichment on the level of skin lesions and behavioral responses in pigs. A total of 648 finishing pigs of both sexes were assessed before and after lairage at the slaughterhouse with a five-point scale (0 = none, to 4 = ≥16 superficial lesions or >10 deep lesions). After lairage (after slaughter), lesions were also classified according to their source (mounting, fighting, and handling). Pigs were distributed into two treatments groups during lairage: with environmental enrichment (EE) on the pen, with hanging metal chains, and with no enrichment (NE). Behavior was monitored during the first four hours of lairage. Proportional odds, mixed linear model for longitudinal data, and non-parametric Wilcoxon signed rank tests were used to analyze the relation between treatments, skin lesions, and behavior. The simple metal chains did not affect skin lesion score or pigs' behavior (p > 0.05), whereas lairage duration influenced standing (SA), sitting (S), lying (L), idleness (I), and drinking water (D) (p < 0.001). The main source of skin lesions was handling, which did not differ between treatments (EE and NE) (p > 0.05). It was observed that the severity of the lesions (highest scores of 3, 4, and 5) increased in the different anatomical regions of the pigs when compared before and after slaughter, with the exception of the frontal area, which was the same (p = 0.7547). Lairage time has a proportional relation with skin lesions, and hanging chains at the slaughterhouse pens was not enough to reduce the number of lesions and to change pig behavior.

Are there differences in the adaptive profile of hair sheep and their crosses with wool breeds?

This study aimed to evaluate and compare the physiological performance of different genetic groups of sheep, by physiological variables and serum hormone levels, in a hot weather environment. Thirty sheep from five genetic groups were used: Santa Inês (SI), ½ Dorper + ½ Santa Inês (DO), ½ Ilê de France + ½ Santa Inês (IF), ½ Suffolk + ½ Santa Inês (SK), and ½ Texel + ½ Santa Inês (TX). The readings and records of physiological parameters (respiratory rate (RR), rectal temperature (RT), auricular cavity temperature (ACT), and surface temperature (ST)) were carried out at 7:00 am, 1:00 pm, and 7:00 pm, in 12 non-consecutive days. The collections of blood samples for hormone analysis (triiodothyronine (T3), thyroxine (T4), and cortisol (CORT)) is in four consecutive days. The environmental conditions of the experimental period caused a thermal discomfort in the sheep, but not a state of thermal stress. The thermolysis mechanisms, sensitive (ST and ACT) and latent (RR) processes, were enough to maintain their homeostasis (RT). The results showed that crossbred breeds presented a higher metabolism and were more efficient at dissipating heat through thermolysis than the SI breed. The crossbred breeds were efficient at dissipating heat through the elevation of body surface temperature and respiratory rate, mainly SK and TX, i.e., crossbred breeds, despite the wool cover, used thermoregulatory mechanisms that promoted lower variation of RT. The analysis of variance showed significant effects (P < 0.05) to the time factor in the responses of T4 and T3, and to the breed factor in the responses of CORT, T4, and T3. We did not observe interaction between the factors to any of the hormonal variables. Therefore, we can state that the effect of time was independent of breed and vice versa. Thyroid hormones presented lower blood concentration in the mornings (4.03 ± 0.82, T4; 65.08 ± 10.6, T3), increasing their concentration in the afternoon (4.60 ± 1.03, T4; 70.16 ± 14.17, T3). The thyroid hormones presented a normal circadian rhythm, with the exception of SK. Air temperature (AT) showed greater correlation with physiological variables than enthalpy (H) did, in the experimental conditions. However, H showed correlation with T4 and T3. The adaptive profile of the genetic groups under study are different, but the IF genetic group showed better performance under environmental conditions.

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 thermophysical responses, carcass traits, and meat quality of finishing pigs.

Environmental enrichment consists of a way to provide better living conditions for animals, but its influence on physical integrity, thermoregulatory responses, and quality of pork meat is not known. The objective of this study was to evaluate the thermoregulatory responses, lesion score, lameness, carcass traits, and meat quality of pigs with and without access to environmental enrichment (EE) in the finishing phase. A total of 432 pigs of the Hampshire lineage, males and females, with average initial and final weights between 22-27 kg and 110-125 kg respectively were evaluated. The experimental design used was in randomized blocks, with 6 treatments, distributed in a 2×3 factorial scheme (sex × environmental enrichment), with 12 repetitions per treatment, totaling 72 stalls. The treatments were branched chain for males (T1), branched sisal rope for males (T2), males without EE (T3), branched chain for females (T4), branched sisal rope for females (T5), and females without EE (T6). Weekly, two assessments of physiological data were performed, in loco, in the morning and afternoon. Lesions on the tail, ear, body, and lameness were evaluated on the 1st, 16th, 37th, 51st, 79th, 93rd, and 112th days. On the 112th day, 72 animals were slaughtered for carcass traits and meat quality analyses. Statistical analysis was performed using generalized and mixed linear models. There was no effect (p>0.05) of the interaction of the studied factors (environmental enrichment × sex × period) on the head, back, leg, and average temperature. However, there was an effect of the period factor (p<0.01), with higher temperatures in the afternoon compared to the morning. For tail injury, there was no association between injury degree and gender (p=0.56) and between injury degree and enrichment (p=0.99), and there was no interaction effect (p=0.15). For ear injury, there was no association between the degree of ear injury and gender (p=0.72), as well as for the degree of ear injury and enrichment (p=0.99) and interaction (p=0.47). There was a higher occurrence of categories 2, 3, and 4 for lesions on the body in males (p=0.0257), regardless of the EE. Water retention, carcass yield, cut yield, marbling pattern, pH, and color showed no effect for sex, enrichment, and interaction between the two factors (p>0.05). The use of environmental enrichment with sisal ropes and branched chains does not change the thermophysical responses, carcass traits, and meat quality of finishing pig.

Oregano essential oil in the diet of laying hens in winter reduces lipid peroxidation in yolks and increases shelf life in eggs.

We evaluated the effects of oregano essential oil (OEO) added to the feed of semi-heavy laying hens during winter. We measured performance as well as physical and chemical quality of fresh and 21-day stored eggs. A total of 240 semi-heavy laying hens were distributed into six treatments and five replicates (n = 8 each). Treatments consisted of five groups of hens fed diets supplemented with 0, 50, 100, 150 and 200 mg OEO/kg. We measured the average of three productive cycles (1st: week 1-4, 2nd: week 5-8 and 3rd: week 9-12), and found that feed consumption increased in hens in the control group and those in the group treated with 200 mg OEO/kg; other zootechnical variables did not differ between treatments. When we analyzed each individual production cycle individually, we did not observe differences between treatments for the performance variables in the first or second cycles. However, in the third cycle, when the animals were exposed to a greater number of days to cold stress, we recorded improved conversion rate/dozen eggs, conversion rate/daily feed consumed and egg production at T50 (50 mg OEO/kg). Stored eggs from hens supplemented with 50 mg OEO/kg showed lower eggshell percentages and higher yolk pHs. The intensity of the yellow was higher in yolks of the control group and in those from hens supplemented with 200 mg OEO/kg. Lipid peroxidation was lower in fresh egg yolks from hens that received 200 mg OEO/kg and stored eggs of T150. The reduction of lipid peroxidation in egg yolk is beneficial to consumer health by reducing levels of free radicals consumed. Reduction of lipid peroxidation associated with 150 mg OEO/kg in laying hens in winter might be useful for maintaining egg quality and for prolonging shelf life; productive efficiency was improving even at 39.8 mg OEO/kg if we consider feed conversion (kg/kg).

Oregano essential oil (Origanum vulgare) to feed laying hens and its effects on animal health.

This study evaluated the effect of oregano essential oil added to the feed of commercial laying hens. This research was focused on the analysis of biochemical changes linked to hepatic function, and protein and lipid metabolism. It was used 240 laying hens (59 weeks-old) distributed in a completely randomized design of six treatments (five repetitions with eight birds each). The experiments were constituted by a control treatment (CT) with the inclusion of zinc bacitracin and five treatments of oregano essential oil (OEO: 0, 50, 100, 150, and 200 mg.kg-1), respectively. After 28 days of feeding, an increase on serum levels of total proteins and globulins was observed on groups T150 and T200, as well as an increase on albumin levels on group CT. After 84 days of feeding, a significant reduction on total proteins and albumin was observed on group T200, as well as an increase in serum triglycerides. OEO at 200 mg.kg-1 increased globulin levels on day 28, which may be considered an effect in the inflammatory response, which increases serum immunoglobulins and proteins.