Temperament influences mitochondrial capacity in skeletal muscle from 8 through 18 mo of age in Brahman heifers

Temperamental cattle tend to yield carcasses of poorer quality, and Brahman cattle are reportedly more temperamental than non-indicus cattle breeds. A potential link between temperament and product quality may be mitochondrial activity. We hypothesized that mitochondrial measures would be greater in temperamental compared with calm heifers and that the relationships between temperament and mitochondria would persist as heifers age. Serum cortisol and skeletal muscle (longissimus thoracis [LT] and trapezius [TRAP]) mitochondrial profiles and antioxidant activities were quantified from the same calm (n = 6) and temperamental (n = 6) Brahman heifers at 8, 12, and 18 mo of age. Data were analyzed using a mixed model ANOVA in SAS (9.4) with repeated measures. Serum cortisol was greater in temperamental compared with calm heifers throughout the study (P = 0.02). Mitochondrial volume density (citrate synthase [CS] activity) increased over time (P < 0.0001) but was similar between temperament and muscle groups. Mitochondrial function (cytochrome c oxidase activity) was greatest in the temperamental LT at 8 mo of age (P ≤ 0.0006), greatest in the temperamental TRAP at 18 mo of age (P ≤ 0.003), and did not differ by temperament at 12 mo of age. Integrative (relative to tissue wet weight) mitochondrial oxidative phosphorylation capacity with complex I substrates (P_CI), P_CI plus complex II substrate (P_CI+II), noncoupled electron transfer system capacity (E_CI+II), and E with functional complex II only (E_CII) were greater in the TRAP than LT for calm heifers at all ages (P ≤ 0.002), but were similar between muscle groups in temperamental heifers. Overall, calm heifers tended to have greater intrinsic (relative to CS activity) P_CI and flux control of P_CI+II (P ≤ 0.1) than temperamental heifers, indicating greater utilization of complex I paired with greater coupling efficiency in calm heifers. Within the LT, integrative P_CI+II was greater (P = 0.05) and E_CI+II tended to be greater (P = 0.06) in temperamental compared with calm heifers. From 8- to 18-mo old, glutathione peroxidase (GPx) activity decreased (P < 0.0001) and superoxide dismutase activity increased (P = 0.02), and both were similar between muscle groups. The activity of GPx was greater in temperamental compared with calm heifers at 8 (P = 0.004) but not at 12 or 18 mo of age. These results detail divergent skeletal muscle mitochondrial characteristics of live Brahman heifers according to temperament, which should be further investigated as a potential link between temperament and product quality.     

Transportation stress in young bulls alters expression of neutrophil genes important for the regulation of apoptosis, tissue remodeling, margination, and anti-bacterial function

The transportation of beef cattle results in a stress response that is associated with increased susceptibility and severity of respiratory diseases, presumably due to an alteration in immune function. Neutrophils are phagocytic immune cells important in lung defense and are also targets of the stress response. The objective of this study was to determine if a 9h transportation of young bulls by road induced changes in the expression of candidate genes known to be important in neutrophil-mediated defense and inflammation in the lung. These neutrophil genes encompassed functions of apoptosis (A1 and Fas), tissue remodeling (MMP-9), vascular margination (L-selectin), bacterial killing (BPI), and wound healing (betaglycan), as well as responsiveness of the cells to stress-induced increases in glucocorticoid hormones (GRalpha). To explore gene expression changes, blood was collected, plasma harvested, and neutrophils isolated from six Belgian Blue x Friesian bulls (231+/-7.0 kg in weight; 282+/-4 days of age) at -24, 0, 4.5, 9.75, 14.25, 24, and 48h relative to commencement of a 9h road transportation by truck. Plasma cortisol concentrations were elevated at 4.5 and 9.75h, peaking at 50.64+/-4.46 ng/mL (P<0.0001) and confirming that the animals experienced stress. Blood neutrophil count was elevated between 4.5 and 14.25h (P<0.0001), reaching a peak that was over 3-fold higher than the -24h concentration. Neutrophil Fas gene expression was acutely down-regulated (P=0.02) by transportation stress, while expressions of MMP-9, l-selectin, and BPI were profoundly up-regulated (P=0.003, 0.002, and <0.001 respectively). However, no changes in neutrophil expressions of betaglycan, GRalpha, and A1 were detected. It is concluded that a 9h transportation of young bulls induces a gene expression signature in blood neutrophils that increases their circulating numbers and may enhance their pro-inflammatory and anti-bacterial potential.     

Effect of 12-hour road transportation on physiological, immunological and haematological parameters in bulls housed at different space allowances

The effects of transporting Holstein Friesian bulls (n=72; bodyweight 403+/-3.5 kg) for 12h by road were examined. Adrenal, haematological and immune responses, body temperature and performance were recorded. The animals had been previously housed for 96 days at three space allowances (1.2, 2.7 or 4.2m(2) per bull). The bulls were allocated to one of two treatments: T (transport for 12h; n=16 per space allowance) and C (control; n=8 per space allowance). Basal cortisol plasma concentrations and interferon (IFN)-gamma production from cultured lymphocytes did not show any statistically significant difference (P>0.05) following the housing period. Removing bulls from their home pens and walking them to the pre-loading crush facility, loading onto the transporter, and unloading following the 12h road journey, significantly (P<0.001) increased plasma cortisol concentration. The bulls housed at 4.2m(2) had greater (P<0.05) plasma cortisol concentrations than bulls housed at 1.2m(2) at loading, unloading, or on return to the crush holding facility; those housed at 1.2m(2) had greater (P<0.05) plasma cortisol concentrations than bulls housed at 2.7 and 4.2m(2) in their home pens after transport. There was an increased (P<0.05) plasma cortisol response in the T than in the C bulls following adrenocorticotrophic hormone administration. Transport significantly reduced (P<0.05) IFN-gamma production, lymphocyte % and body weight and significantly increased (P<0.05) neutrophils, eosinophils, packed cell volume, red blood cell numbers and haemoglobin. In conclusion, housing bulls for 96 days in a range of space allowances did not affect basal cortisol response or immune function parameters. Whereas transport increased plasma cortisol and reduced the immune response in the short-term, the changes were transient and within normal physiological ranges, suggesting that 12h road transport had no adverse effect on welfare status over the longer term. Furthermore, transport of bulls housed at increased space allowance (4.2m(2)/bull) resulted in a greater plasma cortisol response, albeit still within normal physiological range.     

Migration of fish leucocytes in vitro: the effect of factors which may be involved in mediating inflammation

Plaice (Pleuronectes platessa L.) neutrophils were isolated from the kidney on a discontinuous Percoll gradient and from the peritoneal cavity at the peak of a glycogen-elicited inflammatory response. The migratory ability of neutrophils was assessed using a 48-well microchemotaxis chamber, with an incubation of 1.5 h at 12 degrees C. The two neutrophil populations showed different responses to N-formylmethionyl-leucyl-phenylalanine (FMLP). Whereas kidney neutrophils only showed a significant enhancement of migration at 10(-7) M, inflammatory neutrophils exhibited a bimodal response, with one peak of migratory activity at 10(-9) M and a second at greater than 10(-6) M. Kidney neutrophils showed a consistent response with various concentrations of a 24 h culture supernatant of Vibrio alginolyticus. In every case increased migration was observed with 5-, 10- and 100-fold dilutions, with the latter two conditions producing a significant enhancement (p less than 0.01 and p less than 0.05 respectively). The undiluted and 2-fold diluted supernatant caused a decreased cell migration compared with control values. The supernatant from kidney neutrophils cultured with serum-opsonized, heat-killed V. alginolyticus produced greater migratory activity than neutrophils or the treated bacteria incubated alone (the controls). In each case, the enhanced activity of the supernatant was detectable by 1 h of incubation. By 4 h, the activity of the neutrophil/bacteria supernatant was significantly higher than that of the controls (p less than 0.01), but by 24 h had fallen to control levels. There was no evidence for a chemotactic response with FMLP, the bacterial supernatant or the neutrophil-derived factor and the responses were therefore assumed to be chemokinetic.     

Relationships of metabolic hormones and serum glucose to growth and reproductive development in performance-tested Angus, Brangus, and Brahman bulls

Understanding mechanisms that regulate growth and reproduction are important for improving selection strategies in cattle. In this study, Angus, Brangus, and Brahman bulls (n = 7 per breed) of similar age were selected from a group of 65 weanlings. Bulls were evaluated after weaning (i.e., approximately 6 mo of age) for 112 d for serum concentrations of metabolic hormones and glucose, growth, and reproductive traits. Performance data and blood sera were collected on d 0, 28, 56, 84, and 112. Sera were also collected in periods from d 50 to 59 (56D) and 103 to 112 (112D). Angus bulls were heavier (P < 0.05) throughout the study than Brahman bulls and were heavier than Brangus bulls on d 56, 84, and 112. Initial and final BW for Angus, Brangus, and Brahman bulls were 292.7, 260.6, and 230.4 and 468.3, 435.6, and 350.7 +/- 12 kg, respectively. Conversely, Brahman bulls had greater hip height (P < 0.05) than Brangus, and Brangus were taller (P < 0.05) than Angus. Angus bulls had the greatest (P < 0.05) scrotal circumference (SC) and Brahman bulls the least. Mean SC across days was 31.5, 29.7, and 25.0 +/- 0.6 cm for the three respective breeds. Serum testosterone was greater (P < 0.01) in Angus and Brangus bulls (10.0 and 8.9 +/- 1.4 ng/mL) than in Brahman bulls (4.0 +/- 1.4 ng/mL) throughout the study. After d 112, 100, 86, and 57% of the Angus, Brangus, and Brahman bulls passed a breeding soundness exam (P = 0.51). Serum concentrations of IGF-I and leptin were greater (P < or = 0.06) in Angus bulls on d 56, 84, and 112 than in Brangus and Brahman bulls. Serum concentrations of GH (P < 0.08) and glucose (P < 0.03) were greater in Brangus bulls than in Angus or Brahman bulls throughout the study. Prediction analyses suggested that serum concentrations of leptin could be used to predict (P < or = 0.08) BW and SC (R2 > 0.82) in the 56D and 112D periods among these breeds. Leptin was also useful in predicting (P < or = 0.09) serum concentrations of GH and testosterone in the 112D period (R2 > 0.32). Residual correlation analyses with the effect of breed removed suggested that leptin was correlated (r > or => 0.53, P < 0.05) with both SC and serum testosterone. Angus and Brahman cattle differ in phenotype, level of adiposity, and rate of sexual development. Data herein suggest that these characteristics could be due to varying mechanisms by which metabolic hormones such as leptin, GH, and(or) IGF-I are regulated.     

The effects of stressful exercise on leukocytes in cattle with experimental pneumonic pasteurellosis

Seven yearling bulls were treated with stressful exercise and intrabronchial Pasteurella haemolytica A1. Group 1 bulls (nos. 1–4) underwent treadmill exercise and, 24 days later, intrabronchial instillation of P. haemolytica A1. Group 2 bulls (nos. 5–7) underwent treadmill exercise, followed 30 min later by intrabronchial P. haemolytica A1. Blood lactic acid values were raised (p<0.05) by treadmill exercise only, but plasma cortisol was raised (p<0.05) by treadmill exercise and by P. haemolytica A1 infection. Neutrophils in bronchoalveolar lavage (BAL) differed from control values 24 h after treadmill exercise, and 1 h and 4 h after P. haemolytica A1 infection.Respiratory disease was more severe and the gross lung lesions were larger in group 2 bulls than in group 1 bulls. P. haemolytica A1 was recovered from the livers, spleens and mesenteric lymph nodes of group 2 but not group 1 bulls, suggesting that group 2 bulls had experienced bacteraemia. Decreased neutrophils in BAL fluid from group 2 bulls at 1 h and 4 h after infection suggests that exercise transiently inhibited neutrophil egress from the blood to the alveoli; BAL neutrophils peaked at 1 h and 4 h after infection in group 1 bulls but declined at 24 h. We conclude that group 2 bulls were made more susceptible to experimental pneumonic pasteurellosis by stressful exercise.Abbreviations ADCC antibody dependent, cell-mediated cytotoxicity - AM alveolar macrophages - BAL bronchoalveolar lavage - CFU conlony-forming units     

Serial evaluation of neutrophil function in tumour‐bearing dogs undergoing chemotherapy

We hypothesized that neutrophil function in tumour‐bearing dogs is negatively impacted by chemotherapy. Flow cytometric techniques were used to assess neutrophil oxidative burst and phagocytic activities at baseline, 7 and 21 days after induction chemotherapy in 20 dogs with lymphoma. Dogs had a lower percentage of neutrophils exhibiting oxidative burst activity after stimulation with Escherichia coli (day 7; P = 0.009) and phorbol 12‐myristate 13‐acetate (PMA) (days 7 and 21; P = 0.0003 and P = 0.01, respectively), compared with healthy controls. From day 0 to 7, the percentage of neutrophils exhibiting oxidative burst activity decreased after stimulation with E. coli (P = 0.016) and PMA (P = 0.0006). Induction chemotherapy suppresses the percentage of neutrophils capable of oxidative burst in dogs with lymphoma, with improvement in phagocytic activity over time (P = 0.03). The impact of neutrophil dysfunction on incidence and severity of sepsis in dogs receiving chemotherapy should be investigated.     

运输应激对马血细胞和血液生化指标的影响

为了调查运输应激对伊犁马血细胞和血液生化指标的影响,试验选取6匹伊犁母马,进行400 km里程的运输,总运输时间为8 h,分别在运输0、4、8 h和落地12 h后,测定马血清急性期蛋白（APPs）、皮质醇（Cor）、热休克蛋白（HSPs）、干扰素-γ（IFN-γ）和肿瘤坏死因子-α（TNF-α）含量以及血液常规指标。结果显示,与运输0 h相比,运输8 h马触珠蛋白（HP）含量显著上升（P<0.05）,运输4、8 h和落地12 h后马血清Cor含量均极显著上升（P<0.01）;落地12 h后马血清HSP90含量极显著下降（P<0.01）;运输对马血清IFN-γ和TNF-α含量均无显著影响（P>0.05）;运输4、8 h和落地12 h后血液红细胞分布宽度标准差（RDW-SD）、血小板分布宽度（PDW）、血小板大细胞比率（P-LCR）、粒细胞（GRAN）和粒细胞比率（GRAN%）均显著上升（P<0.05）,中间细胞比率（MID%）、中间细胞（MID）、血红蛋白浓度（MCHC）均显著下降（P<0.05）。综上所述,运输应激对马血清HP、Cor、HSP90浓度、血液RDW-SD、PDW、P-LCR、GRAN%、GRAN、MID%、MID和MCHC均产生显著影响,这些指标可用于评价马对运输应激的敏感性。     

Cattle temperament: persistence of assessments and associations with productivity, efficiency, carcass and meat quality traits

Relationships between temperament and a range of performance, carcass, and meat quality traits in young cattle were studied in 2 experiments conducted in New South Wales (NSW) and Western Australia (WA), Australia. In both experiments, growth rates of cattle were assessed during backgrounding on pasture and grain finishing in a feedlot. Carcass and objective meat quality characteristics were measured after slaughter. Feed intake and efficiency during grain finishing were also determined in NSW. Brahman (n = 82 steers and 82 heifers) and Angus (n = 25 steers and 24 heifers) cattle were used in the NSW experiment. In NSW, temperament was assessed by measuring flight speed [FS, m/s on exit from the chute (crush)] on 14 occasions, and by assessing agitation score during confinement in the crush (CS; 1 = calm to 5 = highly agitated) on 17 occasions over the course of the experiment. Brahman (n = 173) and Angus (n = 20) steers were used in the WA experiment. In WA, temperament was assessed by measuring FS on 2 occasions during backgrounding and on 2 occasions during grain feeding. At both sites, a hormonal growth promotant (Revalor-H, Virbac, Milperra, New South Wales, Australia) was applied to one-half of the cattle at feedlot entry, and the Brahman cattle were polymorphic for 2 calpain-system markers for beef tenderness. Temperament was not related (most P > 0.05) to tenderness gene marker status in Brahman cattle and was not (all P > 0.26) modified by the growth promotant treatment in either breed. The Brahman cattle had greater individual variation in, and greater correlations within and between, repeated assessments of FS and CS than did the Angus cattle. Correlations for repeated measures of FS were greater than for repeated assessments of CS, and the strength of correlations for both declined over time. Average FS or CS for each experiment and location (NSW or WA × backgrounding or finishing) were more highly correlated than individual measurements, indicating that the average values were a more reliable assessment of cattle temperament than any single measure. In Brahman cattle, increased average FS and CS were associated with significant (P < 0.05) reductions in backgrounding and feedlot growth rates, feed intake and time spent eating, carcass weight, and objective measures of meat quality. In Angus cattle, the associations between temperament and growth rates, feed intake, and carcass traits were weaker than in Brahmans, although the strength of relationships with meat quality were similar.     

Associations between endotoxin‐induced metabolic changes and temperament in Brahman bulls,

The influence of temperament on the alteration of metabolic parameters in response to a lipopolysaccharide (LPS) challenge was investigated. Brahman bulls were selected based on temperament score. Bulls (10 months; 211 ± 5 kg BW; n = 6, 8 and 7 for Calm, Intermediate and Temperamental groups, respectively) were fitted with indwelling jugular catheters to evaluate peripheral blood concentrations of glucose, blood urea nitrogen (BUN), non‐esterified fatty acids (NEFA), insulin, epinephrine and cortisol before and after LPS administration (0.5 μg/kg BW LPS). Feed intake was also recorded. Intermediate bulls consumed more feed than the Temperamental bulls during the challenge (p = 0.046). Pre‐LPS glucose (p = 0.401) and BUN (p = 0.222) did not differ among the temperament groups. However, pre‐LPS insulin (p = 0.023) was lower, whereas pre‐LPS NEFA (p < 0.001), cortisol (p < 0.001) and epinephrine (p < 0.001) were greater in Temperamental than in Calm and Intermediate bulls. Post‐LPS glucose was increased in Calm and Intermediate bulls but not in Temperamental bulls (p < 0.001). Insulin concentrations post‐LPS were greater in Calm than in Intermediate and Temperamental bulls (p < 0.001). Concentrations of NEFA post‐LPS were greater in Temperamental than in Calm and Intermediate bulls (p < 0.001). Serum BUN concentration increased post‐LPS, with values being greater in Calm and Intermediate than in Temperamental bulls (p = 0.012). Collectively, these data demonstrate that animal temperament is related to the metabolic responses of Brahman bulls following a provocative endotoxin challenge. Specifically, Temperamental bulls may preferentially utilize an alternate energy source (i.e. NEFA) to a greater degree than do bulls of Calm and Intermediate temperaments. The use of circulating NEFA from lipolysis may reduce the negative metabolic consequences of an immune response by allowing for a prompt answer to increasing energy demands required during immunological challenge, compared with the time required for glycogenolysis and gluconeogenesis.     

Effect of location and season on body and testicular growth in Brahman and Hereford bulls

To determine the effects of location and season on growth of bulls, Hereford bulls from Montana (MH; n = 15) and Nebraska (NH; n = 15) and Brahman bulls from Texas and Louisiana (BB; n = 18) were moved to three locations: Montana (MT), Nebraska (NE) or Texas (TX). Each location received 5 NH, 5 MH and 6 BB. Control bulls (not relocated) were maintained at each location. All bulls were pubertal at the time of relocation in May 1984. At 28-d intervals, body weight, hip height, testis length and scrotal circumference were recorded for each bull for 22 mo after relocation. Paired testes volume (PTV) was calculated. Among Hereford bulls, body weights were similar (P greater than .10) in all control and relocated bulls by the end of the study, except that MH bulls moved to TX had lower body weights (P less than .01). Brahman bulls moved to northern locations had dramatically reduced body weights, compared to control Brahmans kept in TX; body weight of Brahman bulls in MT remained lower (P less than .01) at the end of the study. Brahman bulls in NE and MT had smaller scrotal circumference and PTV (P less than .01) than did control Brahmans in TX during the 1st yr after relocation. Relocated BB exhibited marked seasonal fluctuations in testis size, with increases during the summer and decreases during the winter (P less than .01); seasonal changes were not apparent in control Brahmans in TX. These results indicate that moving Brahman bulls to northern environments reduced body weight gain and caused dramatic seasonal changes in testis size; these effects were more pronounced in Brahman bulls moved to the most northern location.     

Banding or Burdizzo castration and carprofen administration on peripheral leukocyte inflammatory cytokine transcripts

The objective was to investigate if Banding or Burdizzo castration of bulls would alter the gene expression profile of a range of peripheral leukocyte inflammatory cytokines (IL-1, IL-6, IL-8, IL-10, interferon-γ and tumor necrosis factor-α) and to determine if the administration of carprofen (C) before castration would affect the expression of these genes. Thirty Holstein-Friesian bulls (5.5 months; Mean 191 ± (SEM) 3.7 kg) were blocked by weight and randomly assigned to one of five treatments: (1) untreated control (CON); (2) Banding castration at 0 min (BAND); (3) BAND following an i.v. injection of 1.4 mg/kg BW of carprofen (C) at −20 min (BAND + C); (4) Burdizzo castration at 0 min (BURD); or (5) BURD following 1.4 mg/kg BW of carprofen at −20 min (BURD + C). Blood samples were collected at 1 h before castration and 6, 24 and 48 h post-castration for routine hematology and quantitative real-time PCR analysis of cytokine gene expression analysis. Generally, there were no differences (P > 0.05) among treatment groups in hematological variables following castration. Cortisol concentrations were unchanged throughout the experimental period in CON bulls. BURD animals had greater cortisol concentrations than BAND and CON animals at 6 h post treatment. Transitory effects were observed only in the expression of IL-6 and TNF-α. The relative expression of IL-6 was greater in the BURD than in the BAND treatment (P < 0.05) at 24 h post-castration and was greater in the BURD + C group than in the BURD group (P < 0.05) at 48 h. The relative expression of TNF-α was greater in BAND than in the BURD group (P < 0.05) at 48 h. In conclusion, these findings indicate that Banding or Burdizzo castration did not have any major effect on peripheral leukocyte inflammatory cytokine gene expression; Banding castration caused a greater pro-inflammatory cytokine gene expression reaction than Burdizzo castration and carprofen administration can affect IL-6 gene expression levels in BURD castrated animals.     

Cortisol response to road transport stress in calm and nervous stallions

Cortisol may be useful as a marker in predicting how an animal will respond to stressful stimuli, thus providing information on animal's temperament. To quantify the level of transport stress and the effect of temperament on the adrenocortical response, the change in circulating cortisol levels was evaluated in 84 healthy experienced thoroughbred and crossbred stallions, mean age 11.4 ± 4.5 years old, after road transport in a commercial trailer (6 horses per load, stocking density: 2 m²/horse), over mean distances of 210 ± 11.8 km for about 3 hours. Several experienced caretakers were asked to complete 2 questionnaires, one that used a 5-point scale to subjectively evaluate temperament and another that used a 3-point scale to assess tendencies in response to ordinary care and daily management. The scores for the latter were defined as follows: a score of 1 indicated that the horse had never or rarely troubled the caretaker during management, 2 occasionally, and 3 usually. On this basis, the subjects were distinguished between calm and nervous stallions. Blood samples were taken same daytime (8.00 am), in single box, immediately before loading, then after transport and unloading. Serum cortisol concentrations were analyzed in duplicate by immunoenzymatic assay. Compared with basal levels, cortisol increases were observed in both calm (P < 0.001) and nervous (P < 0.05) stallions after transport. Repeated-measures analysis of variance showed significant effects of transport on cortisol changes (P < 0.001). Nervous subjects showed lower (P < 0.01) cortisol levels than did calm subjects after transport, and basal cortisol levels did not differ between calm and nervous subjects. No significant differences (P > 0.05) between different age, breed, and orientation were detected.The results showed that temperament could influence the adrenocortical responses of stallions after short-term transportation. The presence of the same staff for handling, loading, confinement, and unloading, the same veterinarian taking all blood samples, and the presence of cospecifics did not reduce the response to short transport stress both in calm and nervous stallions already accustomed to transport. Lower cortisol concentrations in nervous subjects might be because of failure of the adrenal cortex to respond normally to transport stress. Moreover, signs of transport stress were less pronounced in nervous stallions.     

Effect of season and location on semen quality and serum concentrations of luteinizing hormone and testosterone in Brahman and Hereford bulls

Hereford bulls from Montana (MH; n = 15) and Nebraska (NH; n = 15) and Brahman bulls from Texas (BB; n = 18) were relocated to one of three locations (LOC): Montana (MT), Nebraska (NE) or Texas (TX). All bulls were pubertal at the time of relocation in late May 1984. Semen was collected by electroejaculation within 1 wk after relocation and at 90-d intervals beginning in November 1984 through early February 1986. Bulls were given a GnRH challenge (200 micrograms i.m.) during the same week of semen collections. Bulls also were bled for 8 h at 20-min intervals in the fall of 1984 and the spring and fall of 1985 to determine endogenous concentrations of LH and testosterone. Season affected sperm concentration in all breeds (P less than .05) with decreases during the winter in BB and during the summer in NH and MH bulls. Brahman bulls had lower percentage of live cells (LIVE) than NH and MH bulls did (P less than .0001). Brahman bulls decreased in LIVE during the winter (P less than .001). Area under the LH curve after GnRH was lower (P less than .005) in BB than in MH and NH. Brahman bulls in MT had greater (P less than .02) area under the LH curve and lower (P less than .06) area under the testosterone curve than did BB in TX or NE during the winter. There was no seasonal fluctuation in LH or testosterone response to GnRH in NH or MH bulls at any LOC. Area under the endogenous LH curve was lowest (P less than .04) in BB. Basal endogenous testosterone concentration was greater (P less than .03) in NH than in MH or BB. Area under the endogenous testosterone curve was lower (P less than .03) in MH than in NH or BB. These results indicate that BB exhibit seasonal fluctuations in semen quality. This was not so apparent in semen quality traits of Hereford bulls. There also was a seasonal influence in BB on both endogenous testosterone and GnRH-stimulated LH and testosterone concentrations. Compared with Hereford bulls, Brahman bulls had lower endogenous and GnRH-stimulated concentrations of LH.     

Growth and pubertal development in Brahman-, Boran-, Tuli-, Belgian Blue-, Hereford- and Angus-sired F1 bulls

Growth and testicular development between 7 and 15 mo of age were evaluated in bulls produced by mating sires of six breeds (Hereford, Angus, Belgian Blue, Brahman, Boran, and Tuli) to Angus, Hereford, and MARC III (four-breed composite) cows. At 12 mo of age, Angus- and Hereford-sired bulls had the heaviest body weight (P < 0.08 to 0.001), whereas Brahman- and Belgian Blue-sired bulls were intermediate, and Boran- and Tuli-sired bulls weighed the least. Bulls sired by European breeds grew more rapidly after weaning (P < 0.01) than did Brahman-, Boran-, and Tuli-sired bulls, and these differences in growth rate were maintained through 15 mo of age, indicating that offspring of heat-adapted sire breeds (Brahman, Boran, and Tuli) have lower postweaning rates of gain, particularly during winter months, than do offspring of nonheat adapted sire breeds. Testis size was smaller initially (P < 0.01) and remained smaller in offspring of heat-adapted sire breeds through yearling age. By 15 mo of age, testis size was largest (P < 0.06 to 0.001) in Angus-sired bulls and had become similar among Hereford-, Brahman-, Boran- and Belgian Blue-sired bulls but remained smaller (P < 0.02 to 0.001) in Tuli-sired bulls. Thus, offspring of heat-adapted sire breeds had delayed testicular development compared with that of nonheat adapted sire breeds, particularly through yearling age. At puberty, Angus-sired bulls were 23 to 82 d younger (P < 0.05 to 0.001) than all other sire breeds except Hereford, and Brahman-sired bulls were older at puberty (P < 0.05 to 0.001) than were bulls of all other sire breeds except Boran. Testis size at puberty was quite similar among breeds of bulls (scrotal circumference = 27.9 +/- 0.1 cm) despite large breed differences in age, body weight, and hip height. Thus, measurement of yearling testis size was a reliable indicator of age at puberty among widely divergent breeds of bulls. In addition, the lower postweaning rates of gain and the smaller and slower testicular development in offspring of heat-adapted sire breeds should be noted by cattle producers considering use of such breeds in crossbreeding and breed improvement programs.     

猪瘟免疫猪接种PRRSV nsp2Δ1882-2241弱毒疫苗后IL-12、IL-10、TNF-α应答特征

不同时间段采集猪的血液样本,利用ELISA方法检测血清和细胞培养上清中IL-12、IL-10、TNF-α等3种细胞因子的水平,分析猪双重免疫CSFV、PRRSV弱毒苗后血清和细胞培养上清中细胞因子的变化规律。结果显示,IL-12在血清中的浓度显著高于细胞培养上清中的浓度(P<0.01),在CSFV高抗体PRRSV高抗体组中28d采血的细胞培养上清中IL-12的浓度高于14d采血的细胞培养上清中的浓度(P<0.05);IL-10血清中水平显著低于细胞培养上清中水平(P<0.01),在CSFV高抗体PRRSV高抗体组中28d采血的细胞培养上清中的IL-10浓度显著低于14d采血的细胞培养上清中的浓度(P<0.01);TNF-α在血清中水平显著低于细胞培养上清中水平(P<0.01),在3组中28d采血的细胞培养上清液中TNF-α浓度高于14d采血的细胞培养上清液中浓度(P<0.05)。结果表明,2种疫苗特异性抗体应答高时,IL-12水平显著上调,IL-10水平显著下调,提示上调IL-12及下调IL-10都是基因缺失疫苗发挥效力的潜在机制。TNF-α总体水平上升,但在血清中水平较低。     

Effects of Pasteurella haemolytica A1 leukotoxin on bovine neutrophils: degranulation and generation of oxygen-derived free radicals.

To further define the role of Pasteurella haemolytica A1 leukotoxin in the pathogenesis of bovine pneumonic pasteurellosis, its in vitro effects on bovine neutrophils were investigated. Leukotoxin-containing culture supernatant, from P. haemolytica, stimulated a neutrophil respiratory burst as measured by the generation of oxygen-derived free radicals O2- and H2O2. This effect was immediate because preincubation of neutrophils with the culture supernatant for 5 min or longer substantially suppressed this respiratory burst. This suppression was due to cytolysis of the neutrophils. Prolonged incubation of neutrophils with the same culture supernatant caused further cytolysis and degranulation. Heat-inactivated P. haemolytica culture supernatant that had lost its cytotoxic properties failed to stimulate respiratory burst by neutrophils. Furthermore, the respiratory burst, cytolysis and degranulation were abrogated only by leukotoxin-neutralizing monoclonal and polyclonal antibodies, but not by antibodies against the lipopolysaccharide. These studies show that the leukotoxin component in the culture supernatant was responsible for the generation of oxygen-derived free radicals and proteolytic enzymes from neutrophils which may participate in direct lung injury.     

Effect of plasma transfusion on neutrophil function in healthy and septic foals

OBJECTIVE: To evaluate the effect of plasma transfusion on phagocytosis and oxidative burst activity of peripheral blood neutrophils from healthy and septic equine neonates with sub-optimal passive transfer of maternal immunity. ANIMALS: Nine healthy and seven septic foals with suboptimal passive transfer of maternal immunity (serum IgG < 8 g/L) presented to participating veterinary hospitals for plasma transfusion, and seven healthy foals less than 7 days of age and with circulating IgG concentrations > or = 8 g/L. PROCEDURE: Foals with serum IgG concentrations < 8 g/L were assessed as healthy or septic. Sepsis was recognised by positive bacterial cultures and/or sepsis scores of > or = 11. All foals received between 1 and 3 L of plasma to boost circulating IgG concentrations to > or = 8 g/L. Serum IgG concentrations were determined before and following transfusion by glutaraldehyde coagulation test and confirmed by single radial immunodiffusion assays. Neutrophil phagocytosis and oxidative burst activity were determined before plasma transfusion and at 0 h, 12 h, 24 h, 48 h and 5 d following treatment. Neutrophil function from seven healthy foals less than 7 d of age and with circulating IgG concentrations of > or = 8 g/L was similarly evaluated on a single occasion. RESULTS: Plasma treatment significantly increased circulating IgG concentrations for healthy and septic foals. Oxidative burst activity of neutrophils from septic foals was significantly increased 5 days following treatment, relative to 0 h post treatment. Other differences were not significant but suggested a transient decrease in phagocytosis by neutrophils from healthy foals and increased phagocytosis by neutrophils from septic foals immediately following transfusion. Oxidative burst activity of neutrophils from septic foals tended to be less than that of healthy foals at all sampling times. Serum IgG concentrations were not correlated with neutrophil phagocytosis, but were correlated with oxidative burst activity. CONCLUSIONS: Plasma transfusion did not improve neutrophil function of healthy foals, suggesting that such treatment may be of equivocal benefit for healthy neonates. Conversely, improved neutrophil function was observed following treatment of septic foals, suggesting that plasma transfusion was beneficial for these foals. Oxidative burst activity of neutrophils from septic foals was lower than that of neutrophils from healthy foals and was significantly improved 5 days post treatment, when compared with values obtained immediately following treatment.     

Calm Temperament Improves Reproductive Performance of Beef Cows

Profitability of a beef operation is determined by the proportion of cows attaining pregnancy early in the breeding season and those that are pregnant at the end of breeding season. Many factors, including temperament, contribute to those reproductive parameters. The objective of this study was to evaluate effects of temperament on reproductive performance of beef cows. In Experiment 1, Angus and Angus‐cross beef cows (n = 1546) from eight locations were assigned a body condition score (BCS; 1 = emaciated; 9 = obese) and chute exit and gait score (1 = slow exit, walk; calm temperament; 2 = jump, trot or run; excitable temperament). Cows were grouped with bulls (1 : 25 to 1 : 30; with satisfactory breeding potential and free of venereal disease) for an 85‐day breeding season. Pregnancy status and stage of gestation were determined (transrectal palpation) 35 days after the end of the breeding season. Controlling for BCS (p < 0.01) and handling facility (p < 0.0001) and handling facility by temperament score interaction (p < 0.001), breeding season pregnancy rate was lower in excited versus calm cows [88.6% (798/901) vs 94.1% (607/645); p < 0.001]. Cows with an excitable temperament took 24 more days to become pregnant compared to calm cows (median days to pregnancy, 35 vs 59 days; p < 0.0001). In Experiment 2, Angus and Angus‐cross beef cows (n = 1407) from 8 locations were assigned scores for body condition and chute exit and gait (as described in Experiment 1) and assigned to bulls (breeding sound and free of venereal disease; 1 : 25 to 1 : 30) for 85 days. Pregnancy status was determined by transrectal palpation at 2 and 6 months after the onset of the breeding season. Controlling for BCS (p < 0.05), pregnancy loss was higher in excited versus calm cows [5.5% (36/651) vs 3.2% (20/623), p < 0.0001]. In conclusion, beef cows with an excitable temperament had significantly lower reproductive performance than calmer cows. The modified two‐point chute exit–gait scoring method was repeatable and identified cattle with an excitable temperament.