Genomic breeding programs have been paramount in improving the rates of genetic progress of productive efficiency traits in livestock. Such improvement has been accompanied by the intensification of production systems, use of a wider range of precision technologies in routine management practices, and high-throughput phenotyping. Simultaneously, a greater public awareness of animal welfare has influenced livestock producers to place more emphasis on welfare relative to production traits. Therefore, management practices and breeding technologies in livestock have been developed in recent years to enhance animal welfare. In particular, genomic selection can be used to improve livestock social behavior, resilience to disease and other stress factors, and ease habituation to production system changes. The main requirements for including novel behavioral and welfare traits in genomic breeding schemes are: (1) to identify traits that represent the biological mechanisms of the industry breeding goals; (2) the availability of individual phenotypic records measured on a large number of animals (ideally with genomic information); (3) the derived traits are heritable, biologically meaningful, repeatable, and (ideally) not highly correlated with other traits already included in the selection indexes; and (4) genomic information is available for a large number of individuals (or genetically close individuals) with phenotypic records. In this review, we (1) describe a potential route for development of novel welfare indicator traits (using ideal phenotypes) for both genetic and genomic selection schemes; (2) summarize key indicator variables of livestock behavior and welfare, including a detailed assessment of thermal stress in livestock; (3) describe the primary statistical and bioinformatic methods available for large-scale data analyses of animal welfare; and (4) identify major advancements, challenges, and opportunities to generate high-throughput and large-scale datasets to enable genetic and genomic selection for improved welfare in livestock. A wide variety of novel welfare indicator traits can be derived from information captured by modern technology such as sensors, automatic feeding systems, milking robots, activity monitors, video cameras, and

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In utero heat stress (IUHS) increases energy requirements of pigs during postnatal life, and this may compound weaning and transport stress. The study objective was to evaluate and mitigate the negative effects of IUHS following weaning and transport through the provision of a nutrient dense (ND) nursery diet formulated to meet the greater energy requirements of IUHS pigs during the first 14 d post-weaning and transport. Twenty-four pregnant gilts were exposed to thermoneutral (TN; n = 12; 17.5 ± 2.1°C) or heat stress (HS; n = 12; cycling 26°C to 36°C) conditions for the first half of gestation (d 6 to 59) and then TN conditions (20.9 ± 2.3°C) until farrowing. Nine TN gilts and 12 HS gilts produced litters. At weaning (16.2 ± 0.4 d), mixed-sex piglets (N = 160; 4.78 ± 0.15 kg BW) were transported (loading + transport + unloading) for 11 h 40 min. Following transport, piglets were blocked into pens (n = 4 pigs/pen) by in utero and dietary treatments: in utero thermoneutral (IUTN) + control diet (C; n = 10 pens), IUTN + ND (n = 10 pens), IUHS + C (n = 10 pens), IUHS + ND (n = 10 pens). Treatment diets were fed from d 1 to 14 post-weaning and transport (Period 1), and the C diet was fed to all pigs from d 14 to 35 post-weaning and transport (Period 2). Production measures were taken in 7 d intervals to calculate average daily gain (ADG), average daily feed intake (ADFI), average daily net energy intake (ADEI), gain:feed, and gain: net energy intake. Blood samples were collected prior to transport (Pre-T), following transport (Post-T), and on d 2, 7, 14, 28, and 35 post-weaning and transport to analyze cortisol, glucose, insulin, and non-esterified fatty acids (NEFA). Behavior was assessed through video-recording on d 3, 5, 8, 11, and 13 post-weaning and transport. In Period 1, ADG was reduced (P = 0.04; 20.0 g/d) in IUHS vs. IUTN pigs. Pigs fed ND diets had reduced ADFI (P = 0.02; 9.3%) compared to C diet fed pigs during Period 1, which resulted in similar ADEI (P = 0.23; 1,115 ± 35 kcal/d). During transport, cortisol was decreased (P = 0.03; 25.8%) in IUHS vs. IUTN pigs. On d 2, glucose was decreased (P = 0.01; 13.8%) in IUHS vs. IUTN pigs. No in utero treatment-related behavior differences were observed but lying was reduced (P = 0.03; 6.5%) and standing was increased (P = 0.04; 14.1%) in ND vs. C pigs overall. In summary, IUHS reduced growth performance in pigs following weaning and transport and providing a ND diet did not rescue the lost performance.

Gestating sows may be more susceptible to increasing dry bulb temperatures (TDB) due to greater metabolic heat production and increased body mass, especially as gestation advances. However, there are few studies on the thermoregulatory and physiological responses of sows at differing gestation stages exposed to gradually increasing temperatures. The study objective was to determine the thermoregulatory and physiological responses of non-pregnant (n = 12; parity 3.27 ± 0.86), mid-gestation (59.7 ± 9.6 d pregnant, n = 12; parity 3.25 ± 0.83), and late-gestation (99.0 ± 4.8 d pregnant, n = 12; parity 3.33 ± 0.75) sows exposed to increasing TDB. Prior to the experiment (5.0 ± 0.7 d), jugular catheters were placed in all sows. During the experiment, the TDB was increased incrementally by 2.45 ± 0.43°C every 60 min from 19.84 ± 2.15°C to 35.54 ± 0.43°C over 400 min and relative humidity was recorded at 40.49 ± 18.57%. Respiration rate (RR), heart rate (HR), skin temperature, and vaginal temperature were measured, and blood samples were obtained via the jugular catheter every 20 min. Data were analyzed using PROC MIXED in SAS 9.4. Respiration rate increased at a lower TDB (P < 0.01) in late-gestation sows compared to mid-gestation and non-pregnant sows, but no differences were detected between mid-gestation and non-pregnant sows. Overall, late-gestation sows had greater RR [P < 0.01; 23 ± 2 breaths per min (brpm)] compared with mid-gestation (16 ± 2 brpm) and non-pregnant (15 ± 2 brpm) sows. Late-gestation sows had an overall greater HR (P < 0.01; 84 ± 5 beats per min (bpm)) than mid-gestation (76 ± 5 bpm) and non-pregnant (69 ± 5 bpm) sows. Late-gestation sows had overall reduced bicarbonate and total carbon dioxide levels (P = 0.02; 23.89 ± 1.97 mmol/L and 25.41 ± 2.07 mmol/L, respectively) compared to mid-gestation (27.03 ± 1.97 mmol/L and 28.58 ± 2.07 mmol/L, respectively) and non-pregnant (26.08 ± 1.97 mmol/L and 27.58 ± 2.07 mmol/L, respectively) sows. Moreover, late-gestation sows had overall greater nitric oxide levels (P < 0.01; 248.82 ± 34.54 µM) compared with mid-gestation (110.47 ± 34.54 µM) and non-pregnant (41.55 ± 34.54 µM) sows. In summary, late-gestation sows appear to be more sensitive to increasing TDB as indicated by thermoregulatory and physiological responses when compared to mid-gestation or non-pregnant sows. Results from this study provide valuable information regarding thermoregulatory thresholds of sows at differing gestation stages.

Dietary antibiotic use has been limited in swine production due to concerns regarding antibiotic resistance. However, this may negatively impact the health, productivity and welfare of pigs. Therefore, the study objective was to determine if combining dietary synbiotics and 0.20% L-glutamine would improve pig growth performance and intestinal health following weaning and transport when compared to traditionally used dietary antibiotics. Because previous research indicates that L-glutamine improves swine growth performance and synbiotics reduce enterogenic bacteria, it was hypothesized that supplementing diets with 0.20% L-glutamine (GLN) and synbiotics [SYN; 3 strains of Lactobacillus (1.2 x 10 ^9 cfu/g of strain/pig/day) + β-glucan (0.01 g/pig/day) + fructooligosaccharide (0.01 g/pig/day)] would have an additive effect and improve pig performance and intestinal health over that of dietary antibiotics. Mixed sex pigs (N = 226; 5.86 ± 0.11 kg BW) were weaned (19.4 ± 0.2 d of age) and transported for 12 h in central Indiana. Pigs were blocked by BW and allotted to 1 of 5 dietary treatments (5 to 6 pigs/pen): antibiotics (positive control, PC; chlortetracycline [441 ppm] + tiamulin [38.5 ppm]), no antibiotics (negative control, NC), GLN, SYN, or the NC diet with both the GLN and SYN additives (GLN+SYN) fed for 14 d. From d 14 post-weaning to the end of the grow-finish period, all pigs were provided common antibiotic-free diets. Data were analyzed using PROC GLIMMIX and PROC MIXED in SAS 9.4. Overall, haptoglobin was greater (P = 0.03; 216%) in NC pigs compared to PC pigs. On d 13, GLN and PC pigs tended to have reduced (P = 0.07; 75.2 and 67.3%, respectively) haptoglobin compared to NC pigs. On d 34, the jejunal goblet cell count per villi and per mm tended to be greater (P < 0.08; 71.4 and 62.9%, respectively) in SYN pigs compared to all other dietary treatments. Overall, jejunal mucosa tumor necrosis factor-alpha (TNFα) gene expression tended to be greater (P = 0.09; 40.0%) in NC pigs compared to PC pigs on d 34. On d 34, jejunal mucosa TNFα gene expression tended to be greater (P = 0.09; 33.3, 41.2, and 60.0%, respectively) in GLN pigs compared to SYN, GLN+SYN, and PC pigs. Although it was determined that some metrics of pig health were improved by the addition of GLN and SYN (i.e., haptoglobin and goblet cell count), overall there were very few differences detected between dietary treatments and this may be related to the stress-load incurred by the pigs.