Evaluation of sow thermal preference across three stages of reproduction

The metabolic heat production of modern pigs has increased by an average of 16%, compared with sows of 30 years ago. Therefore, it is likely that temperature recommendations require updating to meet the needs of modern pigs. The objective of this study was to evaluate whether different reproductive stages of sows altered thermal preference and if current recommendations required updating. Twenty multiparous sows (3.4 ± 1.2 parity) in different reproductive stages (nonpregnant: n = 7; mid-gestation: 58.5 ± 5.68 d, n = 6; and late-gestation: 104.7 ± 2.8 d, n = 7) were tested. Thermal preference was individually tested, and sows could freely choose a temperature, using a thermal gradient between 10.4 and 30.5 °C. Sows were given 24 h to acclimate to the thermal apparatus. Before testing began, sows were given daily feed allotment and returned to the apparatus. Video from the 24-h test period was used to record sow behavior (time spent inactive), posture (upright and sternal and lateral lying), and location using instantaneous scan samples every 15 min. Data were analyzed using PROC MIXED procedure in SAS 9.4. A cubic regression model was used to calculate the sow’s most preferred temperature based on the location, or temperature, in which they spent the most time. The preference range was calculated using peak temperature preference ±SE for each sow. The reproductive stage altered where sows spent their time within the thermal gradient (P < 0.01). Late-gestation sows preferred cooler temperatures (14.0 °C) than mid-gestation (14.8 °C; P < 0.01) and nonpregnant sows (14.8 °C; P < 0.01). In summary, sow thermal preferences were within the lower half of the current recommended range (10 to 25 °C). This indicates that temperatures at the higher end of the recommended range could be uncomfortable to sows and that the thermal comfort zone of sows may be narrower than recommendations indicate.     

Rapamycin administration during an acute heat stress challenge in growing pigs

Study objectives were to determine the effects of rapamycin (Rapa) on biomarkers of metabolism and inflammation during acute heat stress (HS) in growing pigs. Crossbred barrows (n = 32; 63.5 ± 7.2 kg body weight [BW]) were blocked by initial BW and randomly assigned to 1 of 4 environmental-therapeutic treatments: 1) thermoneutral (TN) control (n = 8; TNCon), 2) TN and Rapa (n = 8; TNRapa), 3) HS control (n = 8; HSCon), or 4) HS and Rapa (n = 8; HSRapa). Following 6 d of acclimation to individual pens, pigs were enrolled in two experimental periods (P). During P1 (10 d), pigs were fed ad libitum and housed in TN conditions (21.3 ± 0.2°C). During P2 (24 h), HSCon and HSRapa pigs were exposed to constant HS (35.5 ± 0.4°C), while TNCon and TNRapa pigs remained in TN conditions. Rapamycin (0.15 mg/kg BW) was orally administered twice daily (0700 and 1800 hours) during both P1 and P2. HS increased rectal temperature and respiration rate compared to TN treatments (1.3°C and 87 breaths/min, respectively; P < 0.01). Feed intake (FI) markedly decreased in HS relative to TN treatments (64%; P < 0.01). Additionally, pigs exposed to HS lost BW (4 kg; P < 0.01), while TN pigs gained BW (0.7 kg; P < 0.01). Despite marked changes in phenotypic parameters caused by HS, circulating glucose and blood urea nitrogen did not differ among treatments (P > 0.10). However, the insulin:FI increased in HS relative to TN treatments (P = 0.04). Plasma nonesterified fatty acids (NEFA) increased in HS relative to TN treatments; although this difference was driven by increased NEFA in HSCon compared to TN and HSRapa pigs (P < 0.01). Overall, circulating white blood cells, lymphocytes, and monocytes decreased in HS compared to TN pigs (19%, 23%, and 33%, respectively; P ≤ 0.05). However, circulating neutrophils were similar across treatments (P > 0.31). The neutrophil-to-lymphocyte ratio (NLR) was increased in HS relative to TN pigs (P = 0.02); however, a tendency for reduced NLR was observed in HSRapa compared to HSCon pigs (21%; P = 0.06). Plasma C-reactive protein tended to differ across treatments (P = 0.06) and was increased in HSRapa relative to HSCon pigs (46%; P = 0.03). Circulating haptoglobin was similar between groups. In summary, pigs exposed to HS had altered phenotypic, metabolic, and leukocyte responses; however, Rapa administration had limited impact on outcomes measured herein.     

In utero heat stress alters the postnatal innate immune response of pigs

The effects of in utero heat stress (IUHS) range from decreased growth performance to altered behavior, but the long-term impact of IUHS on postnatal innate immune function in pigs is unknown. Therefore, the study objective was to determine the effects of early gestation IUHS on the immune, metabolic, and stress response of pigs subjected to an 8 hr lipopolysaccharide (LPS) challenge during postnatal life. Twenty-four pregnant gilts were exposed to thermoneutral (TN; n = 12; 17.5 ± 2.1 °C) or heat stress (HS; n = 12; cyclic 26 to 36 °C) conditions from days 6 to 59 of gestation, and then TN conditions (20.9 ± 2.3 °C) from day 60 of gestation to farrowing. At 12 wk of age, 16 IUHS and 16 in utero thermoneutral (IUTN) pigs were selected, balanced by sex and given an intravenous injection of LPS (2 µg/kg BW mixed with sterile saline [SAL] and injected at 2 µL/kg BW) or SAL (2 µL/kg BW). Body temperature was monitored every 30 min, and blood was obtained at 0, 1, 2, 3, 4, 6, and 8 hr following the LPS challenge. Blood samples were analyzed for glucose, insulin, non-esterified fatty acids (NEFA), cortisol, and cytokine concentrations. In addition, white blood cell counts were determined at 0 and 4 hr. Hour 0 data were used as covariates. Body temperature was increased (P < 0.01) in LPS (40.88 ± 0.08 °C) vs. SAL (39.83 ± 0.08 °C) pigs. Eosinophils tended to be decreased overall (P = 0.09; 43.9%) in IUHS vs. IUTN pigs. Glucose concentrations were reduced overall (P = 0.05; 5.9%) in IUHS vs. IUTN pigs. The NEFA concentrations tended to be greater (P = 0.07; 143.4%) in IUHS-LPS pigs compared with all other treatments, and IUTN-LPS pigs tended to have greater (127.4%) circulating NEFA concentrations compared with IUTN-SAL and IUHS-SAL pigs. Cortisol was increased (P = 0.04) in IUHS-LPS compared with IUTN-LPS pigs at 3 hr (21.5%) and 4 hr (64.3%). At 1 hr, tumor necrosis factor α was increased (P = 0.01; 115.1%) in IUHS-LPS compared with IUTN-LPS pigs. Overall, interleukin-1β (IL-1β) and interleukin-6 (IL-6) were greater (P < 0.04; 281.3% and 297.8%, respectively) in IUHS-LPS pigs compared with all other treatments, and IUTN-LPS pigs had increased IL-1β and IL-6 concentrations compared with IUTN-SAL and IUHS-SAL pigs. In summary, IUHS altered the postnatal cytokine, metabolic, and physiological stress response of pigs during postnatal life, which may have negative implications toward the innate immune response of IUHS pigs to pathogens.     

A water-soluble β-glucan improves growth performance by altering gut microbiome and health in weaned pigs

Beta-glucan has been shown to have a beneficial effect on gastrointestinal health. This experiment was conducted to investigate the effects of β-glucan isolated from Agrobacterium sp. ZX09 on growth performance and intestinal health of weaning pigs. A total of 108 weaned pigs (21 d of age; 6.05 ± 0.36 kg) were randomly divided into 3 groups (6 pens/group; 6 pigs/pen), and the groups were each treated with the following diets: 1) basal diet, 2) basal diet supplemented with 20 mg/kg olaquindox, 3) basal diet supplemented with 200 mg/kg β-glucan, for 21 d. Compared with the control group, pigs fed with 200 mg/kg β-glucan had greaterBW, average daily gain and duodenal villus height to crypt depth ratio (P < 0.05). Olaquindox increased the duodenal or jejunal villus height of pigs compared with β-glucan. Compared with the control group, β-glucan tended to increase the occludin mRNA expression in the jejunum (0.05 < P < 0.10). Beta-glucan enriched the beneficial microbiota in the ileum of pigs (P < 0.05). In conclusion, β-glucan may promote growth performance by improving intestinal health and increasing beneficial microbiota of weaned pigs. The study results will provide valuable theoretical guidance for the utilization of β-glucan in weaned pigs.     

Timing and temperature thresholds of heat stress effects on fertility performance of different parity sows in Spanish herds

High temperature is an environmental factor that impairs sow fertility. In this study, we identified the critical weeks for heat stress effects on aspects of fertility performance, namely weaning-to-first-service interval (WSI) and farrowing rate (FR). We also examined the threshold temperatures above which the fertility performance deteriorated and whether there were any differences between parities regarding heat stress effects or thresholds. Performance data of sows in 142 herds from 2011 to 2016 were matched to appropriate weekly averaged daily maximum temperatures (T_max) from weather stations close to the herds. Two types of ratios (i.e., ratio for WSI and odds ratio for FR) were used to identify the critical weeks for heat stress by comparing the respective measures for two sow groups based on T_max in different weeks around weaning or service events. The ratios for WSI were calculated between groups of sows exposed to T_max ≥ 27 °C or <27 °C in each week before weaning, with the T_max cutoff value based on a recent review study. Similarly, the odds ratios for FR for the two groups were calculated in weeks around service. The weeks with the largest differences in the fertility measures between the two T_max groups (i.e., the highest ratio for WSI and the lowest odds ratio for FR) were considered to be the critical weeks for heat stress. Also, piecewise models with different breakpoints were constructed to identify the threshold T_max in the critical week. The breakpoint in the best-fit model was considered to be the threshold T_max. The highest ratios for WSI were obtained at 1 to 3 wk before weaning in parity 1 and 2 or higher sow groups. The threshold T_max leading to prolonged WSI was 17 °C for parity 1 sows and 25 °C for parity 2 or higher sows. Increasing T_max by 10 °C above these thresholds increased WSI by 0.65, and 0.33 to 0.35 d, respectively (P < 0.01). For FR, the lowest odds ratios were obtained at 2 to 3 wk before service in parity 0, 1, and 2 or higher sow groups. The threshold T_max leading to reductions in FR was 20, 21, and 24 to 25 °C for parity 0, 1, and 2 or higher sow groups, respectively. Increasing T_max by 10 °C above these thresholds decreased FR by 3.0%, 4.3%, and 1.9% to 2.8%, respectively (P < 0.01). These results indicate that the critical weeks for heat stress were 2 to 3 wk before service for FR and 1 to 3 wk before weaning for WSI. The decreases in fertility performance in parity 0 to 1 sows started at temperatures 3 to 8 °C lower than in parity 2 or higher sows.     

Dietary nano chromium picolinate can ameliorate some of the impacts of heat stress in cross-bred sheep

Two studies were conducted to evaluate the effect of nano chromium picolinate (nCrPic) during heat stress (HS) in sheep. In the initial study, 36 Merino × Poll cross-bred sheep were individually penned and allocated to 3 dietary treatments (0, 400 and 800 μg/kg nCrPic) for 8 wk. Body composition was determined at the beginning and end of the experiment using dual energy X-ray absorptiometry. The sheep remained in their dietary groups but were then placed in metabolic cages and randomly allocated within the dietary group to differing ambient temperature regimes, i.e., thermo-neutral (TN) (n = 18) and HS (n = 18), for 3 wk. Dietary nCrPic had no effect on growth performance and body composition during the initial study conducted under TN conditions. Heat stress decreased average daily feed intake (ADFI) (P = 0.002) whereas sheep under HS had reduced average daily gain (ADG) and indeed lost weight (P < 0.001). Dietary nCrPic increased both ADFI (P = 0.041) and ADG (P = 0.049) under both TH and HS conditions such that the performance of sheep receiving supplemental nCrPic and exposed to HS was similar to that of control sheep maintained under TN conditions. Heat stress increased rectal temperature (P < 0.001) and respiration rate (P < 0.001), particularly during the hottest parts of the day as indicated by interactions (P < 0.001) between time of day and thermal treatment. Rectal temperature was lower in sheep fed nCrPic (P = 0.050), particularly under peak HS conditions during the afternoon as indicated by the interactions between dietary nCrPic and time of day (P < 0.001) and dietary nCrPic, thermal treatment and time of day (P = 0.010). Similarly, respiration rate was lower in sheep fed nCrPic under peak HS conditions during the afternoon as indicated by the interactions between dietary nCrPic and thermal treatment (P < 0.001) and dietary nCrPic and time of day (P = 0.030). In conclusion, dietary nCrPic can partially ameliorate the negative effects of HS as indicated by the maintenance of ADFI and decreased physiological responses, such as elevations in rectal temperature and respiration rate.     

Thermoregulatory and physiological responses of nonpregnant,mid-gestation,and late-gestation sows exposed to incrementally increasing dry bulb temperature

Gestating sows may be more susceptible to increasing dry bulb temperatures (T_DB) 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 nonpregnant (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 T_DB. Prior to the experiment (5.0 ± 0.7 d), jugular catheters were placed in all sows. During the experiment, the T_DB was increased incrementally by 2.45 ± 0.43 °C every 60 min from 19.84 ± 2.15 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. RR increased at a lower T_DB (P < 0.01) in late-gestation sows compared with mid-gestation and nonpregnant sows, but no differences were detected between mid-gestation and nonpregnant 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 nonpregnant (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 nonpregnant (69 ± 5 bpm) sows. Late-gestation sows had overall reduced bicarbonate and total carbon dioxide levels (P = 0.02; 23.89 ± 1.97 and 25.41 ± 2.07 mmol/L, respectively) compared with mid-gestation (27.03 ± 1.97 and 28.58 ± 2.07 mmol/L, respectively) and nonpregnant (26.08 ± 1.97 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 nonpregnant (41.55 ± 34.54 µM) sows. In summary, late-gestation sows appear to be more sensitive to increasing T_DB as indicated by thermoregulatory and physiological responses when compared with mid-gestation or nonpregnant sows. The results from this study provide valuable information regarding thermoregulatory thresholds of sows at differing gestation stages.     

Effects of dietary Selenomethionine supplementation on growth performance,antioxidant status,plasma selenium concentration,and immune function in weaning pigs

Background

This study was designed to evaluate the efficacy of DL-selenomethionine (DL-SeMet) supplementation on growth performance, antioxidant status, plasma selenium (Se) concentration, and immune function of weaning pigs. 216 weaning pigs were randomly allocated to 6 treatments with 6 replicates each according to a complete randomized block design. Each replicate had six pigs. Diet of group one was corn-soybean basal diet without any additional Se supplement. Group 2 was supplemented with 0.3 mg/kg of Se from sodium selenite. Groups 3-6 were supplemented with 0.1, 0.3, 0.5, and 0.7 mg/kg of Se from DL-SeMet, respectively. The trial lasted for 42 days.

Results

Pigs supplemented with 0.3 and 0.7 mg/kg DL-SeMet obtained better feed gain ratio (P < 0.05). The best antioxidant ability (serum, liver, and muscle) was shown in 0.1-0.3 mg/kg DL-SeMet groups (P < 0.05). The plasma Se concentration increased as the dietary DL-SeMet level elevated. The immunity among groups was not affected.

Conclusions

DL-SeMet supplementation in the diet significantly improved the growth performance, antioxidant ability and plasma Se content of weaning pigs. DL-SeMet can replace sodium selenite in the diet of weaning pigs.     

Temperature Related Absorption and Excretion of Sulphadimidine in Rainbow Trout,Salmo Gairdneri

The main purpose of the present study was to see if a kinetic model and a computer program for characterizing the rate of uptake and clearance of chemicals in aquatic organisms (Biofac, OECD’s Chemicals Testing Programme) was applicable to pharmacokinetic studies in fish. The program seems suitable for such studies.The effect of temperature upon rate of absorption of sulphadimidine from medicated water and elimination of the same drug was investigated in rainbow trout. A rise in the temperature from 7° C to 14° C more than doubled the calculated rate constants of absorption and elimination. The biological half life (t_½ β) and the time to reach 90 % of steady state (t_{90% ss}) at 14° C were approximately half the values at 7° C.     

Effects of Thermal Conditioning and Folic Acid on Methylation of the BDNF Promoter Region in Chicks

This study aimed to investigate the effects of thermal conditioning and folic acid on the methylation levels of the avian brain-derived neurotrophic factor (BDNF) promoter region at the M3 and M9 positions in the early life of broiler chicks. In Experiment 1, male broiler chicks (day 3 of life) were orally injected with methyl cellulose solution with or without folic acid (25 mg). The chicks in the heat-treatment groups were immediately exposed to a high ambient temperature (40±0.5°C) for 12 h, while chicks in the non-heat treatment groups were left in the thermoneutral zone (30±0.5°C). The groups were as follows: 1) no thermal conditioning group without folic acid (control), 2) thermal conditioning group without folic acid, 3) no thermal conditioning group with folic acid, and 4) thermal conditioning group with folic acid. In Experiment 2, treatments were similar to those in Experiment 1, except for the usage of female chicks. After the treatments, the methylation levels of the BDNF promoter in chicks were determined using semiquantitative PCR. There were no significant differences between groups in the levels of methylation at the M3 position in both males and females as a result of thermal conditioning and folic acid treatment. Interestingly, significant effects of thermal conditioning and folic acid treatment on methylation at the M9 position were found. BDNF methylation levels at M9 significantly decreased following thermal conditioning, while folic acid suppressed demethylation in both male and female chicks. These data suggest that folic acid and thermal conditioning affects DNA methylation patterns in the central nervous system of chicks, regardless of sex.     

Yeast-based nucleotide supplementation in mother sows modifies the intestinal barrier function and immune response of neonatal pigs

In the present study, we aimed to evaluate the effects of maternal yeast-based nucleotide (YN) supplementation on the intestinal immune response and barrier function in neonatal pigs, as well as the diarrhoea rate and growth performance in suckling piglets. Sixty-four late-gestation sows were assigned to the following groups: the CON (fed a basal diet) and YN groups (fed a basal diet with 4 g YN/kg diet). The experiment started on d 85 of gestation and ended on d 20 of lactation. Diarrhoea rate and average daily gain of the piglets were recorded, and samples of blood and intestines from neonatal piglets were collected before they consumed colostrum during farrowing. Compared with the CON group, maternal YN supplementation increased the weaning weight of litter and decreased the diarrhoea rate (P < 0.01). In addition, maternal YN supplementation promoted the ileal villus development in the neonates compared with that in the CON group (P < 0.01). Maternal YN supplementation also increased the ileal secretory immunoglobulin A (sIgA) level compared with that in the CON group (P < 0.05). The real-time PCR results showed that maternal dietary YN supplementation increased the jejunal and ileal expression of interleukin (IL)-17, IL-8, IL-1β, IL-10 and tumor necrosis factor (TNF)- α in the neonates compared with that in the CON group (P < 0.05). Overall, maternal nucleotide supplementation improved the villus development and innate immunity of neonatal piglets during late pregnancy. This may be associated with the decrease in diarrhoea and the increase in weaning weight of the litter of suckling piglets.     

Formulation of a rational dosage regimen of ceftiofur hydrochloride oily suspension by pharmacokinetic-pharmacodynamic (PK-PD) model for treatment of swine Streptococcus suis infection

BackgroundOur previously prepared ceftiofur (CEF) hydrochloride oily suspension shows potential wide applications for controlling swine Streptococcus suis infections, while the irrational dose has not been formulated.ObjectivesThe rational dose regimens of CEF oily suspension against S. suis were systematically studied using a pharmacokinetic-pharmacodynamic model method.MethodsThe healthy and infected pigs were intramuscularly administered CEF hydrochloride oily suspension at a single dose of 5 mg/kg, and then the plasma and pulmonary epithelial lining fluid (PELF) were collected at different times. The minimum inhibitory concentration (MIC), minimal bactericidal concentration, mutant prevention concentration (MPC), post-antibiotic effect (PAE), and time-killing curves were determined. Subsequently, the area under the curve by the MIC (AUC_0–24h/MIC) values of desfuroylceftiofur (DFC) in the PELF was obtained by integrating in vivo pharmacokinetic data of the infected pigs and ex vivo pharmacodynamic data using the sigmoid E_max (Hill) equation. The dose was calculated based on the AUC_0–24h/MIC values for bacteriostatic action, bactericidal action, and bacterial elimination.ResultsThe peak concentration, the area under the concentration-time curve, and the time to peak for PELF''s DFC were 24.76 ± 0.92 µg/mL, 811.99 ± 54.70 μg·h/mL, and 8.00 h in healthy pigs, and 33.04 ± 0.99 µg/mL, 735.85 ± 26.20 μg·h/mL, and 8.00 h in infected pigs, respectively. The MIC of PELF''s DFC against S. suis strain was 0.25 µg/mL. There was strong concentration-dependent activity as determined by MPC, PAE, and the time-killing curves. The AUC_0–24h/MIC values of PELF''s DFC for bacteriostatic activity, bactericidal activity, and virtual eradication of bacteria were 6.54 h, 9.69 h, and 11.49 h, respectively. Thus, a dosage regimen of 1.94 mg/kg every 72 h could be sufficient to reach bactericidal activity.ConclusionsA rational dosage regimen was recommended, and it could assist in increasing the treatment effectiveness of CEF hydrochloride oily suspension against S. Suis infections.     

Comparison of performance of F1 Romanov crossbred ewes with wool and hair breeds during fall lambing and body weight and longevity through six production years

The objective of this study was to evaluate wool (Dorset and Rambouillet) and hair (Dorper, Katahdin, and White Dorper) breeds for their ability to complement Romanov germplasm in an annual fall lambing system by estimating direct maternal grandsire and sire breed effects on economically important lamb and ewe traits. After 3 yr of evaluation under spring lambing, ewes of the five F1 types were transitioned to spring mating, exposed to composite terminal sires, and evaluated under a barn lambing system at 4, 5, and 6 yr of age. A total of 527 first generation crossbred (F1) ewes produced 1,151 litters and 2,248 lambs from 1,378 May exposures. After accounting for differences in dam age, birth type, and sex, lamb survival to weaning was unaffected by maternal grandsire breed (P = 0.30). However, lambs born to 50% Dorset (16.8 ± 0.21 kg) or 50% White Dorper ewes (16.8 ± 0.28 kg) were heavier at weaning than those born to 50% Katahdin dams (13.8 ± 0.32 kg; P < 0.001). Additionally, lambs born to 50% Dorset ewes were heavier than those born to 50% Rambouillet (16.0 ± 0.22 kg) and 50% Dorper ewes (15.7 ± 0.33; P ≤ 0.03), but no other pairwise maternal grandsire breed differences were observed (P ≥ 0.06). Ewe body weight (n = 3,629) was recorded prior to each of six possible mating seasons and, across ages, was greatest for Dorset- and Rambouillet-sired ewes (56.7 ± 0.44 and 56.5 ± 0.45 kg, respectively), intermediate for Dorper- and White Dorper-sired ewes (54.7 ± 0.78 and 54.1 ± 0.64 kg, respectively), and least for Katahdin-sired ewes (51.5 ± 0.45 kg). Fertility after spring mating (0.80 ± 0.03 to 0.87 ± 0.02), litter size at birth (1.46 ± 0.09 to 1.71 ± 0.07), and litter size at weaning (1.25 ± 0.06 to 1.46 ± 0.06) were not impacted by sire breed (P ≥ 0.16). Ewe longevity, assessed as the probability of being present after 6 production years, was also not affected by sire breed (0.39 ± 0.03 to 0.47 ± 0.03; P = 0.44). Rambouillet-sired ewes weaned more total weight of lamb (21.5 ± 0.94 kg) than Katahdin-sired ewes (17.8 ± 0.94 kg; P = 0.05), but no other sire breed differences were detected (P ≥ 0.07). Results demonstrated that incorporating the Romanov into a crossbreeding system is a practical means of improving out-of-season ewe productivity.     

Association between in-transit loss, internal trailer temperature, and distance traveled by Ontario market hogs

An observational study was conducted from July to October 2004 to determine the association between in-transit losses of swine and internal trailer temperature after controlling for loading density, trip distance, herd size, and random trip effect. A convenience sample of 3 trucking companies was used to collect temperature, relative humidity, and global positioning data for 104 trips that delivered 21 834 pigs from 371 producers to Ontario abattoirs. The association between in-transit loss and trailer temperature was determined using the 90th percentiles of internal temperature for each trip. Average loading density was 0.36 m²/100 kg pig (range 0.28 to 0.50 m²/100 kg pig). Average in-transit loss was 0.12%; however, 94% of producers experienced no losses. As the 90th percentile of internal trailer temperature increased from a range of 8.6°C to 23.3°C to a range of 23.4°C to 26.1°C, average in-transit loss ratio increased approximately 3-fold, with an additional 2-fold increase as the range increased from 26.2°C to 28.9°C to 29.0°C to 30.5°C. As the 90th percentile of temperature increased by 1°C over the full range of temperatures in this study, in-transit loss was expected to increase 1.26 times. The in-transit loss was expected to decrease 0.81 times for each 50-km increase in distance traveled between the farm and the abattoir.     

Concentration and heritability of immunoglobulin G and natural antibody immunoglobulin M in dairy and beef colostrum along with serum total protein in their calves

Immunoglobulin (Ig) G and natural antibody (NAb) IgM are passively transferred to the neonatal calf through bovine colostrum. Maternal IgG provides pathogen- or vaccine-specific protection and comprises about 85% of colostral Ig. NAb-IgM is less abundant but provides broad and nonspecific reactivity, potentially contributing to protection against the dissemination of pathogens in the blood (septicemia) in a calf’s first days of life. In the dairy and beef industries, failure of passive transfer (FPT) of colostral Ig (serum total protein [STP] <5.2 g/dL) is still a common concern. The objectives of this study were to: (1) compare colostral IgG concentrations and NAb-IgM titers between dairy and beef cows; (2) assess the effect of beef breed on colostral IgG; (3) compare passive transfer of colostral Ig in dairy and beef calves; and (4) estimate the heritability of colostral IgG and NAb-IgM. Colostrum was collected from Holstein dairy (n = 282) and crossbred beef (n = 168) cows at the University of Guelph dairy and beef research centers. Colostral IgG was quantified by radial immunodiffusion and NAb-IgM was quantified by an enzyme-linked immunosorbent assay. In dairy (n = 308) and beef (n = 169) calves, STP was estimated by digital refractometry. Beef cows had significantly greater colostral IgG (146.5 ± 9.5 standard error of the mean [SEM] g/L) than dairy cows (92.4 ± 5.2 g/L, P <0.01). Beef cows with a higher proportion of Angus ancestry had significantly lower colostral IgG (125.5 ± 5.8 g/L) than cows grouped as “Other” (142.5 ± 4.9 g/L, P = 0.02). Using the FPT cutoff, 13% of dairy and 16% of beef calves had FPT; still, beef calves had a significantly larger proportion with excellent passive transfer (STP ≥6.2 g/dL, P <0.01). The heritability of colostral IgG was 0.04 (±0.14) in dairy and 0.14 (±0.32) in beef. Colostral NAb-IgM titers in dairy (12.12 ± 0.22, log₂ [reciprocal of titer]) and beef cows (12.03 ± 0.19) did not differ significantly (P = 0.71). The range of NAb-IgM titers was 9.18–14.60, equivalent to a 42-fold range in antibody concentration. The heritability of colostral NAb was 0.24 (±0.16) in dairy and 0.11 (±0.19) in beef cows. This study is the first to compare colostral NAb-IgM between dairy and beef cows. Based on the range in NAb-IgM titers and the heritability, selective breeding may improve colostrum quality and protection for neonatal calves in the early days of life.     

Effects of increased ambient temperature and supplemental altrenogest before pregnancy establishment in gilts

Heat stress (HS) mitigation strategies are critically needed to combat the substantial economic effects on animal agriculture. The manifestations of seasonal infertility include delayed puberty onset, reduced conception rates, decreased litter size, and increased wean to estrus interval. To assess the effects of HS during early gestation and evaluate the benefit of supplemental altrenogest (ALT) as a mitigation strategy, 30 crossbred postpubertal gilts (157 ± 11 kg body weight) were subjected to estrous synchronization via 14 d oral administration of ALT. Artificial insemination during estrus was performed, and gilts were then placed into one of four treatment groups: HS (35 ± 1 °C for 12 h/31.60 ± 1 °C for 12 h) with (HSALT, n = 7) or without (HSCON, n = 7) 15 mg/d ALT supplementation or thermal neutral (TN; 20 ± 1 °C) conditions with (TNALT, n = 8) or without (TNCON, n = 8) 15 mg/d ALT supplementation until 12 d post-estrus (dpe). Administrating ALT occurred at 0600 hours from 3 to 12 dpe, and rectal temperatures (T_R) and respiration rates (RR) were recorded. Blood was collected via jugular venipuncture on 0, 4, 8, and 12 dpe. Gilts were euthanized humanely at 12 dpe followed by the collection of ovarian tissue, and uterine flushing for conceptus collection. In HS compared with TN gilts, RR and T_R were increased (P < 0.01) but unaffected by ALT supplementation. Feed intake was reduced (P < 0.01) by HS but unaltered by the ALT treatment. Corpora lutea (CL) weight was reduced (P < 0.01) in HSCON gilts when compared with TNCON and HSALT gilts despite progesterone concentrations in serum and luteal tissue not being affected by treatment (P ≥ 0.10). CL diameter was reduced (P ≤ 0.05) in HSALT gilts compared with other treatments. Interleukin-1β (IL1B) uterine flush concentration was not affected (P > 0.20) by environment or ALT supplementation, although moderate (P = 0.06) interaction between environment and ALT existed, as IL1B concentration in TNALT was increased (P = 0.03) compared with TNCON gilts. While environment did not affect conceptus development (P = 0.90), ALT supplementation advanced conceptus elongation (P < 0.01). Collectively, these data demonstrate that HS may affect luteal development before pregnancy establishment, and ALT increases conceptus elongation by 12 dpe.     

Comparison between core temperatures measured telemetrically using the CorTemp? ingestible temperature sensor and rectal temperature in healthy Labrador retrievers

This study evaluated the CorTemp^® ingestible telemetric core body temperature sensor in dogs, to establish the relationship between rectal temperature and telemetrically measured core body temperature at rest and during exercise, and to examine the effect of sensor location in the gastrointestinal (GI) tract on measured core temperature. CorTemp^® sensors were administered orally to fasted Labrador retriever dogs and radiographs were taken to document sensor location. Core and rectal temperatures were monitored throughout the day in 6 resting dogs and during a 10-minute strenuous retrieving exercise in 6 dogs. Time required for the sensor to leave the stomach (120 to 610 min) was variable. Measured core temperature was consistently higher than rectal temperature across all GI locations but temperature differences based on GI location were not significant (P = 0.5218). Resting dogs had a core temperature that was on average 0.4°C above their rectal temperature with 95% limits of agreement (LoA) between 1.2°C and −0.5°C. Core temperature in exercising dogs was on average 0.3°C higher than their concurrent rectal temperature, with LoA of +1.6°C and −1.1°C.     

Pulmonary Clearance of Bacillus subtilis Spores in Pigs

The pulmonary clearance rate of Bacillus subtilis was determined in ten pigs (23-39 kg) exposed simultaneously for 15 minutes to an aerosol generated by an ultrasonic nebulizer. Two pigs were killed at each interval of zero, two, four, eight and 12 hours and the concentrations of B. subtilis in lungs (all lobes), dorsal and ventral nasal turbinates, trachea, pharyngeal and bronchial lymph nodes were determined. The mean percent (± standard error) pulmonary clearance of B.subtilis was 54.2±11.7, 53.0±11.8, 77.4±5.2 and 88.1±3.7 at two, four, eight and 12 hours, respectively. The numbers of B. subtilis retained in the posterior (caudal and accessory) lobes at zero time were significantly greater than those in the anterior (cranial and middle) lobes (P<0.05). However, by 12 hours postinoculation the numbers of organisms retained in the two regions did not differ significantly (P>0.05). The mean percentage of B. subtilis retained by the turbinates, trachea, pharyngeal and bronchial lymph nodes varied between pigs at each time interval, but was usually less than that retained by the lungs.

It was concluded that deposition of B. subtilis spores took place in all parts of the respiratory tract when pigs were exposed to aerosols and that the spores were progressively cleared by the normal lung.

     

Comparison of tibial plateau angles in small and large breed dogs

Cranial cruciate ligament (CCL) disease can affect dogs of all sizes. The literature describing tibial plateau angle (TPA) in small breed dogs is limited. A retrospective study was conducted in unselected dogs presented for stifle or tibial examination to compare TPA in small breed dogs (n = 146 dogs, 185 stifles) versus large breed dogs (n = 200 dogs, 265 stifles). Small breed dogs had a mean TPA 3.1° ± 0.6° higher than large breed dogs. There were higher TPAs in spayed females and castrated males for all dogs compared with intact males (3.6° ± 1.0° and 2.7° ± 1.0°, respectively). Dogs with unilateral and bilateral CCL disease had higher TPAs compared to dogs with intact CCLs (2.0° ± 0.7° and 2.5° ± 0.8°, respectively). Tibial morphology differs between large and small breed dogs; however, the significance of the impact of TPA on CCL disease in small breed dogs is unknown.     

Effects of dietary Forsythia suspensa extract supplementation to lactating sows and nursery pigs on post-weaning performance,antioxidant capacity,nutrient digestibility,immunoglobulins, and intestinal health

The aim of this study was to determine the effect of dietary Forsythia suspensa extract (FSE) supplementation to lactating sows and nursery pigs on post-weaning performance, antioxidant capacity, immunoglobulins, and intestinal health. Based on backfat, body weight (BW), and parity, 24 gestating sows (Landrace × Yorkshire) with average parity of 3.38 ± 0.61 and BW of 234 ± 6.81 kg were allotted into two dietary treatments (control vs. 100 mg/kg FSE) with 12 sows per treatment from day 107 of gestation to day 21 of lactation. After weaning, based on the initial BW and source litter, 192 nursery pigs (Duroc × [Landrace × Yorkshire], average BW of 6.98 ± 0.32 kg, weaned at day 21) were allotted into four dietary treatments with eight replicate pens per treatment, six pigs per pen for a 4-wk study. The treatments included the following: 1) CC (sows and their piglets both fed control diet); 2) CF (sows fed control diet and their piglets fed FSE diet [containing 100 mg/kg FSE]); 3) FC (sows fed FSE diet and their piglets fed control diet); and 4) FF (sows and their piglets both fed FSE diet). The MIXED procedures of SAS for a split-plot arrangement with sow diet as the whole plot and nursery diet as split plot were used to analyze the data. After weaning, piglets from FSE-fed sows had improved (P < 0.05) average daily gain and feed efficiency, and lower (P < 0.05) diarrhea rate in overall (day 1 to 28) compared with those from sows fed control diet. Piglets from FSE-fed sows also had higher (P < 0.05) contents of immunoglobulin G (IgG), growth hormone, superoxide dismutase (SOD), total antioxidant capacity in serum, villus height in ileum, and villus height to crypt depth ratio in jejunum, as well as lower (P < 0.05) content of malondialdehyde (MDA) in serum and crypt depth in ileum compared with those from sows fed control diet. Piglets fed FSE during nursery had increased (P < 0.05) concentrations of IgG, SOD, and catalase, and decreased (P < 0.05) MDA and tumor nuclear factor-α levels in serum compared with those fed control diet during nursery. Piglets from FC group had increased (P < 0.05) protein expression of occludin in jejunal mucosa and relative abundance of Lactobacillus on genus level in colon compared with those from CC group. In conclusion, for the performance and intestinal health, diets supplemented with FSE during lactation phase seemed more efficient to alleviate weaning stress than the nursery phase. In terms of the antioxidant status and immunoglobulins, FSE supplemented in both phases were efficient for nursery pigs.