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Prenatal insults have well-documented effects on the postnatal performance of multiple species. Negative effects range from reduced growth rates and altered post-absorptive metabolism to increased frequency of metabolic disease and teratogenicity. While the effects of heat stress (HS) on postnatal pig performance are well-defined, the postnatal consequences of in utero HS on swine physiology and performance have only recently been described. In utero HS (IUHS) has an immediate impact on litter characteristics and decreases offspring birth weight, which is likely an effect of reduced gestation length and in utero growth retardation. In addition to the immediate impact on offspring characteristics, a variety of postnatal bioenergetic and metabolic consequences resulting from IUHS have been described. Prenatal HS imprints a lasting increase on core body temperature set-point in pigs. Since heat loss depends on thermal gradients, a permanent core body temperature increase would reduce an animal's ability to dissipate excess body heat, which has implications towards HS tolerance and survivability. Additionally, maintaining a greater core body temperature set-point would likely decrease energy efficiency due to increased thermogenesis and recent reports indicate that maintenance costs of IUHS pigs are increased during the growing phase. Feed efficiency is also reduced during postnatal life in IUHS pigs compared to in utero thermoneutral (IUTN) pigs despite similarities in feed consumption and this may be due to either the aforementioned increase in maintenance costs or altered postnatal body composition in which adipose tissue is deposited at the expense of lean tissue during the finishing phase. Because lean tissue accretion is more efficient than adipose tissue accretion, depositing adipose at the expense of lean tissue may lead to inefficiencies in the conversion of feed energy to body mass. Furthermore, the predisposition towards gaining adipose tissue may be a result of increased insulin production by IUHS pigs during postnatal life, since insulin is a lipogenic and antilipolytic hormone. Taken together, these data have implications towards the efficiency of converting feed energy to high quality animal protein in prenatally heat-stressed pigs. [ABSTRACT FROM AUTHOR]

Recently, our lab determined that supplementing nursery diets with 0.20% L-glutamine improved health and productivity of weaned and transported piglets in a controlled environment. Therefore, study objectives were to determine the impact of replacing dietary antibiotics with 0.20% L-glutamine on growth performance and health status of piglets following weaning and transport in a production environment during the hot summer months. In July 2016, 246 mixed sex piglets (5.64 ± 0.37 kg BW; Duroc × [Landrace × Yorkshire]) were weaned (19 d of age), loaded onto a trailer, and transported for 12 h. During transport, ambient temperature (28.5 ± 0.3°C) and relative humidity (61.6 ± 1.1%) in the trailer were monitored in 5-min intervals, feed and water were withheld, and intra-abdominal temperature of 6 sentinel piglets was monitored every 10 min (39.7 ± 0.1°C). Following transport, 240 piglets were unloaded, blocked by BW, and randomly allotted to 1 of 3 dietary treatments (n = 10 pens/treatment [8 piglets/pen]). Treatments were dietary antibiotics (AB; chlortetracycline [441 mg/kg] + tiamulin [38.6 mg/kg]), no dietary antibiotics (NA), or 0.20% L-glutamine (GLU) fed for 14 d (Period 1). Following Period 1, all pigs were provided a common antibiotic-free diet until d 34 (Period 2). Data were analyzed using PROC MIXED in SAS 9.4. In Period 1, ADG tended to be greater (P = 0.06) in AB pigs (234 ± 11 g/d) compared with NA pigs (194 ± 11 g/d), with GLU pigs (213.0 ± 11 g/d) being intermediate and not different from AB and NA pigs. During Period 2, ADG increased (P = 0.03) in AB pigs (455 ± 9 g/d) versus NA pigs (420 ± 9 g/d); however, no differences were observed in GLU pigs (443 ± 9 g/d) compared with AB and NA pigs. Overall, AB and GLU increased ADG (P < 0.01; 359 ± 8 g/d) compared with NA (329 ± 8 g/d), but no differences were detected between AB and GLU pigs. Feed efficiency was improved overall (P = 0.03) for AB piglets (681 ± 13) compared with NA piglets (633 ± 13); however, no G:F difference was detected for GLU pigs (647 ± 13) versus AB and NA pigs. No ADFI differences (P > 0.11; 538 ± 13.1 g/d) were detected. Treatments for enteric challenges were greater overall (P = 0.02) in NA piglets (4.9 ± 1.5%) compared with GLU (1.5 ± 1.5%) and AB piglets (1.5 ± 1.5%). In conclusion, 0.20% L-glutamine supplementation improved piglet health and productivity similarly to dietary antibiotics following weaning and transport during the summer. [ABSTRACT FROM AUTHOR]

The goal of the study was to test the hypothesis that feeding a diet containing near optimal AA profile to lactating sows increases ME utilization efficiency for milk production. Thirty-nine lactating multiparous sows were allotted to 1 of 3 diets: Control 19.60% CP (CON), near ideal AA profile 14.22% CP + crystalline AA (OPT) and as OPT + Leu to create an imbalanced profile. Energy balances (EB) were conducted early lactation (EL, d 4-7) and peak lactation (PL, d 14-17). In EL, compared to Control, EB did not differ for sows fed OPT and was lower (P < 0.05) for sows fed OPTLEU. Compared to OPT, EB of sows fed OPTLEU did not differ. Compared to Control, maternal energy retention did not differ in sows fed OPT and OPTLEU and between sows fed OPT and OPTLEU. Milk energy output (Mcal/d) did not differ between Control (9.83 ± 0.91), OPT (10.73 ± 0.91) and OPTLEU (10.53 ± 0.91). In PL, EB did not differ between OPT and Control, and was lower (P < 0.01) for sows fed OPTLEU compared to Control and OPT. Compared to Control, maternal energy retention was lower (P < 0.01) in OPT and OPTLEU. Milk energy output (Mcal/d), compared to Control (12.37 ± 0.89) was greater (P < 0.01) in sows fed OPT (16.65 ± 0.89) and did not differ in sows fed OPTLEU (13.82 ± 0.89). Compared to OPT, milk energy output was lower (P < 0.05) for sows fed OPTLEU. In EL compared to Control, energy efficiency (EE) did not differ in OPT and OPTLEU, and were 71, 83 and 79 % ± 5, respectively. In PL compared to Control, EE was greater (P < 0.05) in OPT and did not differ for OPTLEU, and were 66, 83, and 73% ± 5, respectively. Heat production (HP) associated with milk yield did not differ between Control, OPT and OPTLEU in EL and were 65.3, 42.2 and 43.9 ± 18.5 kcal/(d·BW0.75), respectively. In PL, compared to Control, HP tended to be lower (P = 0.081) in OPT and did not differ for OPTLEU, with HP values of 107.8, 63.3 and 93.9 ± 17.1 kcal/(d·BW0.75). Sows fed a diet with near ideal AA profile have greater energy partitioning to milk production and have higher EE utilization for milk. Adding Leu to create an imbalance reduced the EE utilization and partitioning of energy to milk. [ABSTRACT FROM AUTHOR]

The effects of pen location on swine thermoregulation and productivity were determined for 27 d during late summer. A total of 128 mixed sex pigs (1/2 Duroc x 1/4 Landrace x 1/4 Yorkshire) were randomly assigned to 16 pens in two grow-finish barns [n = 8 pens/barn; 57.4 ± 1.3 kg initial body weight (BW)]. Pen locations were pre-determined based on initial airflow (m/s) level [n = 4 high airflow (HAF) pens/barn and 4 low airflow (LAF) pens/barn]. High airflow and LAF pen locations were identical between each barn. Two sentinel gilts/pen were selected and vaginal temperature (TV) was measured daily in 10 min intervals using thermochron temperature loggers. Additionally, whole body skin temperature (TS) was measured with an infrared camera, and respiration rate (RR) was measured by counting flank movement of the sentinel gilts daily (0800h, 1500h). Pen airflow was measured daily (0800h, 1500h) with a vane anemometer. Ambient temperature (TA) and relative humidity (RH) within each pen were recorded daily in 10 min intervals. Average daily gain (ADG) and average daily feed intake (ADFI) were determined bi-weekly. Data were analyzed using PROC MIXED in SAS 9.4. Although airflow was lower overall (P = 0.04; 11%) in LAF compared to HAF pens, no differences (P > 0.56) in TA (27.63 ± 0.25°C; range 17.80-35.57°C) or RH (68.47 ± 0.46%; range 39.99-98.52%) were detected. An overall increase (P < 0.03) in TV (0.23°C), minimum TV (0.18°C), and maximum TV (0.29°C) was detected in LAF versus HAF pens. Similarly, from 0800-1900h and 2000-0700h, TV was greater overall (P < 0.02; 0.22 and 0.25°C, respectively) in LAF compared to HAF pens. A decrease in TS (P = 0.04) was observed in LAF (37.39 ± 0.14°C) compared to HAF (37.61 ± 0.14°C) pens. No RR differences (P > 0.60; 76 ± 4 bpm) were detected with any comparison. While no ADG or ADFI differences were detected (P > 0.16; 0.75 ± 0.02 kg/d and 2.26 ± 0.07 kg/d, respectively), feed efficiency was decreased (P = 0.04; 6%) in LAF compared to HAF pens. No barn differences were detected with any comparison. In summary, pigs located in LAF pens had greater body temperature and reduced feed efficiency despite similarities in TA and RH. These data have implications towards management of ventilations systems within swine facilities and the impact of pen-to-pen environmental variation on thermoregulation and productivity of pigs during hot summer months. [ABSTRACT FROM AUTHOR]