Histological characteristics and stereological volume assessment of the ovine tonsils

Tonsils form a first line of defence against foreign antigens and therefore play a key role in immunity. Since documented information about ovine tonsils is limited, a study was performed in which the morphological characteristics and the volume of lymphoid tissue present in each ovine tonsil were determined. The tonsils of five adult healthy sheep were examined histologically and the volumes were estimated using the Cavalieri method. The pharyngeal tonsil had a mean volume of 1296.1 ± 205.9 mm³ and was by far the largest ovine tonsil, followed by the paired palatine tonsil with a mean volume of 715.0 ± 110.5 mm³. The tonsil of the soft palate, the paired tubal and paraepiglottic tonsils and the lingual tonsil were much smaller with a mean volume of, respectively, 90.3 ± 24.9 mm³, 80.1 ± 24.3 mm³, 29.7 ± 11.8 mm³ and 10.1 ± 2.8 mm³. The folds and crypts of the pharyngeal and palatine tonsils were covered by a reticular and a non-reticular epithelium. Both tonsils were mainly composed of primary and secondary lymph follicles. The palatine tonsils contained 1–3 crypts with a few secondary infoldings. Lymphoid tissue in the tonsil of the soft palate was located at the nasopharyngeal (dorsal) side of the soft palate. The tubal tonsil was lined with a pseudostratified columnar ciliated epithelium and consisted of scattered lymphoid cells and lymph follicles. The paraepiglottic tonsil consisted of lymph follicles and aggregated lymphoid cells. Its overlying keratinized stratified squamous epithelium was folded and often heavily infiltrated by lymphocytes. The ovine lingual tonsil was not macroscopically visible and did not contain clearly distinguishable lymph follicles. It consisted of aggregations of lymphoid cells that were mainly located within the vallate lingual papillae.     

Influences of lipopolysaccharide-induced immune challenge on performance and whole-body protein turnover in weanling pigs

The objective of this study is to characterize the influence of immune stress induced by lipopolysaccharide (LPS) on protein utilization and turnover for early-weaned pigs. A total of 15, crossbred weanling pigs (initial body weight 10.15 ± 0.39 kg) were assigned to one of three treatments. Pigs were injected with LPS and fed ad libitum (LPS-challenge), or injected with endotoxin-free physiological salt solution (PSS) and fed ad libitum (control), or injected with PSS and fed the same amount of feed as LPS-challenged pigs (pair-feed). All pigs received a 4-d nitrogen balance trial. On d 1 and 3 of the trial, LPS-challenged pigs were injected intramuscularly with 200 μg/kg BW of LPS dissolved in 1 ml PSS. Pigs in other treatments were injected with 1 ml PSS. ¹⁵N-Glycine (5 mg/kg BW) was gastrically infused after the second injection. Feces and urine were collected daily to determine the N output throughout the duration of the trial. Lymphocyte blastogenesis (LB) and serum immunoglobulins (IgA, IgG, IgM) were also detected to illustrate the LPS-induced immune responses. Results indicated that the injection of LPS significantly (P < 0.01) elevated the LB and resulted in lower average daily gain (ADG), feed intake (ADFI) and efficiency of feed utilization than control pigs. Pair-fed pigs had higher performance than LPS-challenged pig but poorer than control pigs. Injection of LPS also resulted in significantly (P < 0.01) lower nitrogen intake and efficiency of utilization than controls, and more fecal N excretion than Pair-fed pigs (3.19 ± 0.85 vs. 2.19 ± 0.67 g/d, P < 0.05). The whole-body nitrogen flux (4.34 ± 0.19 vs. 11.35 ± 0.12 g N/kg BW^0.75/d) and N accretion (5.57 ± 0.59 vs. 10.17 ± 1.12 g Pr/kg BW^0.75/d) were acutely (P < 0.01) reduced as the feed intake decreased, but there was no significant difference between LPS-challenged and pair-fed pigs. Injection of LPS markedly (P < 0.05) increased the protein degradation (16.76 ± 1.09 vs. 14.53 ± 1.24 g N/kg BW^0.75/d). It is concluded that LPS-induced immune challenge depresses growth performance and feed utilization efficiency by enhancing protein degradation rate and decreasing protein utilization for body protein retention.     

H9N2亚型禽流感病毒SD18株的传染性及不同途径感染效果比较

【目的】 研究H9N2亚型禽流感病毒(Avian influenza virus,AIV)对哺乳动物的传染性和致病性。【方法】 采集样品进行病毒的分离鉴定,将分离到的病毒以300 μL/只(10⁷ EID₅₀)的剂量通过滴鼻和肺递送方式感染豚鼠,每组各15只,对2组感染效果进行比较,然后通过分离株在豚鼠中的传播能力试验验证其气溶胶传播能力,通过间接免疫荧光试验检测分离株在人支气管上皮细胞上的复制能力。【结果】 试验分离到1株H9N2亚型AIV,命名为SD18,病毒通过肺递送和滴鼻2种攻毒方式感染豚鼠后,肺递送组的排毒量显著高于滴鼻组(P<0.05)。通过对豚鼠肺脏相关模式识别受体和抗病毒蛋白的表达检测发现,2种攻毒方式都能诱导相关的免疫因子Toll样受体3(TLR3)、TLR7、抗黏病毒蛋白(MX)和2',5'-腺苷酸激酶(OAS)表达量极显著上调(P<0.01);2组在攻毒后第6天产生抗体,并呈上升趋势。对SD18 株在豚鼠中的传播能力验证发现,SD18株具有通过直接接触和飞沫传播感染豚鼠的能力,但并未证实气溶胶的产生和传播。对SD18株感染人支气管上皮细胞BEAS-2B后发现,在感染后12 h可检测到病毒,24 h时病毒在细胞内复制能力最强,TLR3、TLR7、MX、OAS、白介素6(IL-6)、IL-8、干扰素-β(IFN-β)相关的免疫因子表达量极显著上调(P<0.01)。【结论】 H9N2亚型AIV SD18株的跨种传播能力变强,具有不经提前适应便可直接感染豚鼠的能力;SD18株具有通过飞沫传播感染豚鼠并使其产生抗体的能力且SD18株可在人支气管上皮细胞BEAS-2B上进行复制。     

Studies on the pathogenesis of bovine ephemeral fever in experimental cattle III. Virological and biochemical data

In an attempt to define the nature of the response of cattle to ephemeral fever infection, a number of indicators of inflammation were monitored during clinical disease. The total Ca, Zn, Fe, Cu, glucose and phosphate in plasma, together with blood ammonia, were assayed relative to changes in the rectal temperature. Ca_T levels fluctuated markedly and hypocalcaemia occurred in 4 of 8 cattle. Plasma Zn and Fe values fell while plasma Cu levels rose markedly in all cattle. Mean levels of serum NH₃ of 20–30 μmol 1⁻¹ rose to a peak value of 56 μmoll⁻¹. Plasma glucose levels rose to a peak of 4.6 ± 0.5 mMl⁻¹ and the plasma phosphate levels fell from 2.4 ± 0.1 mMl⁻¹ to 1.17 ± 0.2 mMl⁻¹ during fever. Values of pCO₂ fell from a mean of 46.9 ± 3.6 mmHg to 36.4 ± 3.1 mmHg and coincided with a rise in pH. Virus was isolated 73 h (± 23) after inoculation and persisted until 130 h (± 21). The common role of these parameters in generalised inflammation and ephemeral fever is discussed.     

Experimental model of enterotoxigenic Escherichia coli infection in pigs: potential for an early recognition of colibacillosis by monitoring of behavior.

The hypothesis that altered behavior is a sign for an early recognition of disease was tested. The experiment was conducted to evaluate the behavioral patterns of pigs in a model of postweaning colibacillosis. Twenty-five weaned pigs (from a herd that was previously found to be highly susceptible to F4⁺ Escherichia coli strains) were randomly assigned into 5 groups, kept in isolated pens under the controlled ambiental conditions. One day after weaning, the pigs from three groups were intragastrically inoculated (via orogastric tube) with either F4ac⁺ (1466 or 2407) or F4⁻ (1467) nonenterotoxigenic E. coli (non-ETEC) strains, respectively. The pigs from the fourth group were inoculated with F4ac⁺ ETEC strain M1823 and the remaining 5 pigs that received broth containing 1.2% sodium bicarbonate were kept as noninoculated controls. The pigs were examined daily and the frequency and duration of their behavioral patterns, such as eating, drinking, lying, standing, urinating, defecating, rooting and playing were monitored for 300 h during a period of 10 days. In this model, three conditions were also observed in F4-susceptible pigs: (1) acute fatal diarrheal disease; (2) moderate diarrhea and weight loss and (3) no diarrhea and weight loss. The incidence (both frequency and duration) of defecating was significantly higher (P<0.05) in pigs inoculated with F4ac⁺ ETEC strain M1823 as compared to that of noninoculated (control) pigs. Pigs inoculated with F4ac⁺ non-ETEC strain 1466 had a significantly lower frequency of eating (P<0.05) and frequency/duration of drinking (P<0.05) than did the controls. The 1466-inoculated pigs, had an increased diarrhea score, but frequency/duration of defecating was not significantly different. Pigs inoculated with F4ac⁺ non-ETEC strain 2407 spent more time in lying (P<0.05) than did noninoculated pigs. Conversely, the pigs that received F4⁻ non-ETEC strain 1467 laid shorter (P<0.05) and ate/drank less frequently (P<0.05) than the controls. It was concluded that the changed occurrence of defecating and eating in pigs that were inoculated with either F4ac⁺ ETEC (M1823) or non-ETEC (1466) strain, respectively, was consistent with the pending clinical disease, i.e. postweaning colibacillosis.     

Effect of zearalenone on early pregnancy in guinea pigs

Female guinea pigs were tested to determine whether they could serve as a model of zearalenone (ZEN) toxicosis during early pregnancy, as observed in domestic swine. Only 1 of 4 female guinea pigs that were given 21 mg of ZEN/kg of body weight orally during the first 8 days after mating was pregnant when examined 22 days after mating. Guinea pigs that were given 7 or 14 mg of ZEN/kg had normal fetal development. Serum concentrations of progesterone were less than 12 ng/ml in all guinea pigs 8 and 15 days after mating. Serum concentrations of progesterone were greater than 100 ng/ml in pregnant guinea pigs on day 22, but remained less than 12 ng/ml in nonpregnant guinea pigs. Three of 5 guinea pigs treated with 20 mg of ZEN/kg and only 1 of 4 guinea pigs given 30 mg of ZEN/kg on days 1 to 3 after mating were pregnant 22 days after mating. Female guinea pigs treated with 20 or 30 mg of ZEN/kg on days 4 to 5 or 6 to 8 after mating and female guinea pigs treated with 60 or 90 mg of ZEN/kg on days 4 and 5 after mating had normal pregnancies. Serum concentrations of progesterone were less than 10 ng/ml in all guinea pigs on day 15 and remained low on day 22 only in nonpregnant guinea pigs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Impact of controlled fermentation and steeping of high moisture corn on its nutritional value for pigs

High moisture corn (HMC) can undergo fermentation during storage that may improve its nutritional value for pigs. Stored HMC used in this study contained (n = 4) 75% dry matter (DM), and, on a DM basis, 63.8% starch, 0.5% mono and disaccharides, 9.9% protein, 19 mM acetic acid, 18 mM lactic acid (LA), 1.25 × 10⁷ cfu g^− 1 of LA producing bacteria, 2.88 g kg^− 1 total phosphorus (P), and 1.26 g kg^− 1 soluble P. The soluble P content was higher than in freshly harvested HMC (0.27 g kg^− 1 DM) and indicates P release during storage. Studies were aimed at altering the nutritional value of stored HMC by controlled fermentation or steeping. Changes in LA content were not affected (P > 0.05) by addition of exogenous Lactobacillus and Bacillus bacteria. Steeping of HMC with phytase (Ronozyme) was examined at four inclusion levels (0, 500, 750, 1000 FTU kg^− 1) and at either 21 °C or 37 °C. At 37 °C added phytase released virtually all phytate P within 6 h irrespective of the level (levels increased by 1.44 g P kg^− 1 DM); at 21 °C, the increase was maximized at 1.2 g P kg^− 1 DM after 24 h. The feeding value of HMC for pigs can be altered by steeping with exogenous phytase and does not appear to require microbial inoculants.     

Na(+), K(+)-ATPase content in skeletal muscle of dogs with pituitary-dependent hyperadrenocorticism

Several hormones regulate Na⁺, K⁺-ATPase content in the muscle cell membrane, which is essential for maintaining muscle cell excitability. Chronic glucocorticoid excess is associated with muscle weakness and reduced endurance. We hypothesized that chronic glucocorticoid excess affects Na⁺, K⁺-ATPase content in canine skeletal muscle, and contributes to reduced endurance and muscle weakness associated with pituitary-dependent hyperadrenocorticism (PDH) in dogs. Therefore, Na⁺, K⁺-ATPase content in skeletal muscle was evaluated before and after hypophysectomy and hormone replacement (cortisone and l-thyroxin) in dogs with PDH (n = 13), and in healthy controls (n = 6). In addition, baseline and exercise-induced changes in plasma electrolyte concentrations and acid–base balance were evaluated before and after hypophysectomy in dogs with PDH. Na⁺, K⁺-ATPase content of gluteal muscle in dogs with PDH was significantly lower than in control dogs (201 ± 13 pmol/g versus 260 ± 8 pmol/g wet weight; P < 0.01). Similar differences were found in palatine muscle. After hypophysectomy and on hormone replacement, Na⁺, K⁺-ATPase was increased (234 ± 7 pmol/g wet weight). Both plasma pH and base excess in dogs with PDH (7.44 ± 0.01; 1.7 ± 0.6 mmol/l, respectively) were significantly higher (P < 0.05) than after hypophysectomy and hormone replacement (7.41 ± 0.01; −0.2 ± 0.4 mmol/l, respectively). Exercise induced respiratory alkalosis, but did not result in hyperkalemia in dogs with PDH. In conclusion, chronic glucocorticoid excess in dogs with PDH is associated with decreased Na⁺, K⁺-ATPase content in skeletal muscle. This may contribute to reduce endurance in canine PDH, although dogs with PDH did not exhibit exercise-induced hyperkalemia. Na⁺, K⁺-ATPase content normalized to values statistically not different from healthy controls after hypophysectomy and hormone replacement.     

An analysis of mortality in the grower/finisher phase of swine production in the United States

Over a 6-month period, the mean mortality risk (based on 393 operations participating in the United States National Animal Health Monitoring System 1995 National Swine Study, and representing operations with ≥ 300 market hogs in 16 states), was 2.3 ± 0.2% in the grower/finisher production phase (where figures after the ± represent the standard error of the estimate). Mortality ≥ 4% was experienced by 13.5 2.9% of grower/finisher operations, while 63.6 ± 5.3% had ≤ 2% mortality. To identify factors associated with ≥ 4% mortality, stepwise logistic regression [Statistical Analysis Systems, (1989). SAS/STAT^® User's Guide, Version 6, 4th edn, Vol. 2. SAS Institute, Cary, NC, 794 pp.]was performed twice: once using operations with all mortality rates, and again excluding operations with between 2% and 4% mortality. Final models were run with SUDAAN [Shah, B.V., Barnwell, B.G., Bieler, G.S., (1996). SUDAAN User's Manual, Version 6.40, 2nd edn. Research Triangle Institute, Research Triangle Park, NC, 492 pp.] to take the sample design into account. In addition, SAS and SUDAAN logistic regression models were developed to analyze factors associated with > 2.3% mortality among grower/finisher pigs. Mean weaning age ≤ 28 days entered all models as being associated with increased mortality in the grower/finisher unit. Not obtaining all grower/finisher pigs from farrowing units belonging to the operation was associated with ≥ 4% mortality among grower/finisher swine. Not typically giving grower/finisher pigs antibiotics or other agents as disease-preventives or growth-promotants in the feed or water, and ranking producer organizations as very or extremely important sources of antibiotic information were associated with ≤ 2.3% mortality in the grower/finisher phase.     

Responses of female lambs to Rev-1 (brucellosis) vaccination

In order to investigate Rev-1 vaccination immunogenicity, 60 indigenous (Makuii) non-infected female lambs 3–4 months of age in northwestern Iran were systematically divided into two groups: 40 into a treatment (T) group and 20 into a control (C) group. Lambs in Group T received 1 ml of Rev-1 vaccine by s.c. injection and blood samples were collected from both groups at 15 days and 2, 4, 6, 8, 10, 12 and 14 months after vaccination. The seroagglutination test (SAT) and the 2-mercaptoethanol test (2-MET) were carried out on the sera. Control lambs were negative in all the examinations. The results of the SAT showed that the mean( ± SD) antibody titre of lambs in Group T was maximum (725 ± 112 IUml⁻¹) at Day 15, then declined gradually until the fourth month and was in the normal range (31 IU ml⁻¹) thereafter. The results of the 2-MET were negative in Group C but in Group T the antibody titre was at a maximum level (161.7 ± 46.6 IUml⁻¹) at Day 15, decreased to 1.2 ± 2.5IUml⁻¹ at 4 months post-vaccination and was negativ; thereafter. In the second part of the trial, 20 vaccinated and ten control lambs received 0.25 ml melitin by i.d. injection 10.5 months after vaccination. The control group showed no reaction but 13 (65%) of the vaccinated lambs showed an oedematous swelling at the site of injection within 48 h, which indicated that the delayed-type hypersensitivity test (DTHT) could be useful in the diagnosis of Brucella infection in lambs. In the third stage of the experiment, four vaccinated and three control lambs were injected with Brucella melitensis strain 16M at a rate of more than 123 × 10⁶ bacteria per lamb 14 months after vaccination. Rectal temperature (Tem), heart-rate (HR) and respiration rate (RR) were measured three times a day (at 08:00, 14:00 and 21:00 h) 3 days before until 9 days after injection. SAT was carried out on the day before injection and at the time of slaughter. The mean Tem, HR and RR did not significantly change but the mean( ± SD) SAT titre in the T lambs 9 days after injection was 47.5 ± 9.9 IU ml⁻¹ (vs. 8.66 ±6.1 IU ml⁻¹ in the control lambs) (P < 0.01). All lambs were slaughtered on the ninth day. Fewer bacterial cultures of samples taken from the uterus, spleen, liver and lymph nodes were positive in T lambs compared with the controls. The lower proportion of Brucella-positive lambs in the vaccinated group compared with the control group indicates that vaccination with Rev-1 improved the resistance of lambs to the experimental infection.     

Milk production in Holstein cows supplemented with different levels of ruminally protected methionine

Forty multiparous cows (599 kg ± 18 kg BW) were fed with a basal diet (19.6% CP, 35% RUP, and 1.7 Mcal kg^− 1 NEl) with alfalfa, corn silage and concentrate (49% forage: 52% concentrate). After calving, cows were randomly assigned to the treatments, which consisted in four levels of ruminally protected methionine (RPM): 0, 8, 16 and 24 g d^− 1 of Mepron®M85 (Degussa Co.). Experiment was conducted for 120 days with measurements of milk production, composition, body weight, body condition score and DM intake every 15 days (3 consecutive days) starting on day 5 postpartum. Data were analyzed with the repeated measures model (four treatments in 8 periods through lactation). No treatment effects were detected on DM intake (20.38 ± 2.51 kg d^− 1), body weight (599.78 ± 19.78 kg), body condition score (2.51 ± 0.19 units) and milk fat. However, milk production and protein yield were increased with addition of RPM (P < 0.01). Milk production responded quadratically to methionine level. Holstein cows with a mean production of 35 kg d^− 1 milk require addition of ruminally protected methionine (16 g d⁻¹) to improve milk production.     

The C bicarbonate dilution technique to determine energy expenditure in young bulls validated by indirect calorimetry

We explored the applicability of the ¹³C bicarbonate dilution technique for determination of energy expenditure (EE) in young bulls in comparison to whole body indirect calorimetry (IC). Twelve bulls of a F2 German Holstein x Charolais cross (4.5 months, 332 ± 16 kg BM) received a diet providing 1000 kJ ME d^− 1 kg BM^− 0.75 and 4.3 g crude protein d^− 1 kg BM^− 0.75. Bulls were housed in respiration chambers and received an intravenous bolus of NaH¹³CO₃ (A: 3 μmol kg BM^− 1 (n = 2), B: 7 μmol kg BM^− 1 (n = 4), C: 17.5 μmol kg BM^− 1 (n = 6), 99 at.% ¹³C) into the jugular vein to measure EE. Simultaneously, EE was determined by IC. After the ¹³C administration blood samples and breath gas were collected from the animals in the respiration chamber during a 24-h period (7.00–7.00 h). The recovery of ¹³C in breath CO₂ (% of ¹³C dose) was irrespective of NaH¹³CO₃ dose (A: 69.7 ± 2.7%, B: 70.5 ± 4.5%, C: 75.0 ± 4.9%; P > 0.05). Only small amounts of ¹³C were excreted in urine (3.4 ± 2.6%) and feces (2.0 ± 1.3%). The EE determined by the ¹³C bicarbonate method using breath and blood ¹³C recovery rates as correction factors was not different from that measured by IC (816 ± 81 [blood] or 827 ± 101 [breath] vs. 820 ± 90 kJ d^− 1 kg BM^− 0.75). Bland–Altman analysis showed a 95% confidence interval for EE of ± 99 and ± 109 kJ d^− 1 kg BM^− 0.75 based on blood and breath ¹³C recovery, respectively. In conclusion, the ¹³C bicarbonate dilution method is appropriate to obtain reliable estimates of EE in young bulls using blood CO₂ or breath CO₂ under standardized experimental conditions, i.e. in the fasting state.     

Studies on activation and levels of haemolytic complement of buffalo (Bubalus bubalis). II. Alternate complement pathway activity in serum.

Buffalo serum caused lysis of unsensitized red blood cells (RBC) of sheep, goat, rabbit and guineapig. There was minimal lysis of cattle RBC, and homologous RBC were resistant. Lysis of sheep and goat RBC was the result of natural antibodies as adsorption with respective RBC and addition of 8 mmol ethylene glycolbistetraacetate (EGTA) in diluent completely abrogated the haemolytic activity. The lysis of guinea-pig and rabbit RBC was only partially decreased by these treatments, indicating the presence of alternate complement pathway (ACP) activity in buffalo serum. The guinea-pig RBC were the most sensitive to lysis, and 50% CH titre units above 40 ml⁻¹ of serum were obtained. The haemolytic activity of buffalo C for unsensitized guinea-pig RBC was reduced from 47 CH₅₀ units to an undetectable level by heating at 50°C for 20 min and at 56°C for 4 min. Similarly, treatment with zymosan also inhibited this haemolytic activity. Maximum activation of buffalo ACP occurred in the presence of 4 mmol Mg²⁺ in the diluent.

Using standardized conditions, ACP activity was determined in sera of 98 healthy buffaloes of different age groups from 1 month to 12 years. Even young calves less then three months of age showed considerable ACP activity (45.60±1.21 CH₅₀ units ml⁻¹) which increased with age. The peak mean values of 79.79±1.45 CH₅₀ units was recorded in 2 to 4-year-old animals. However, in all the 11 animals above 4 years of age, the haemolytic activity was greatly reduced and was even less than that in 1 to 3-month-old buffalo calves. Haemolytic activity did not vary between the sexes.     

Comparison of scratching behaviour of growing pigs with sarcoptic mange before and after treatment, employing two distinct approaches

In a closed pig breeding and finishing herd suffering from sarcoptic mange, two selected groups of pigs were filmed during a period of 10 days before and after treatment. The observation always commenced each hour and lasted for 15 min. Before treatment, observations was done round the clock, after treatment from 8:00 to 22:15.

Before treatment the pens were stocked with 11 (pen A) and 10 (pen B) growing pigs (Large White × Landrace sows; 5 months old) with an average weight of 70 kg examined for sarcoptic mange by skin scrapings and ELISA. The animals had never been treated with an acaricide or endectocide before.

After 10 days, the pigs were treated twice (18 days interval) with Dectomax^® 1% solution for pigs (Pfizer, Austria) at a dose of 0.3 mg Doramectin i.m./kg body weight. After treatment, seven pigs were observed in both pens.

Most scratching actions both before (83.1%) and after (94.5%) treatment were of one to 10 s. After treatment, the 10 s-scratching episodes decreased by 67.3% (from 21.2 to 6.9 mean SRE/pig), and the scratching actions of longer than 10 s by 91.7% (from 4.3 to 0.4 mean SRE/pig), such that the latter could be observed only occasionally after treatment.

A distinct increase in scratching activity both before and after treatment could be observed primarily between 10:00 and 15:00. Significant differences of scratching and rubbing activity between before and after treatment could also be seen at midday.

The interpretation of the scratching index values before and after the treatment were carried out according to Cargill et al. [Cargill, C., Davies, P., Carmichael, I., Hooke, F., Moore, M., 1994. Treatment of pigs with doramectin to control sarcoptic mange. Proceedings of the 13th IPVS Congress, Bangkok, Thailand, p. 238] with the maximum and minimal limiting values specified in the literature, and compared with calculations using the method described by Hollanders et al. [Hollanders, W., Harbers, A.H.M., Huige, J.C.M., Monster, P., Rambags, P.G.M., Hendrikx, W.M.L., 1995. Control of Sarcoptes scabiei var. suis with ivermectin: influence on scratching behaviour of fattening pigs and occurence of dermatitis at slaughter. Vet. Parasitol. 58, 117–127].

Depending on the methods used and the limiting values set, 6.7–34.6% of the observations before and 2.0–17.3% of the observations after treatment revealed a “strong evidence of mange” or a “suspicion of mange”. All other observations indicated that the pigs were free from mange.     

Mortality attributed to respiratory problems among finisher pigs in the United States

In the 1995 National Swine Study of the United States National Animal Health Monitoring System, producers identified respiratory problems as the leading cause of death in pigs during the grower/finisher phase of production. Over a six-month period, 61.7±4.1% (mean±SEM) of operations reported at least one death attributed to respiratory problems among finisher pigs (based on 388 operations representing operations with ≥300 finisher pigs in 16 states). Mean mortality attributed to respiratory problems was 0.9±0.1% of finisher pigs per operation. Stepwise logistic regression (using SAS) was used to identify factors associated with operations attributing at least one death to respiratory problems, and to identify factors associated with reporting ≥2% mortality attributed to respiratory problems. Final models were run with SUDAAN to account for the sampling strategy. Attributing at least one death to respiratory problems was associated with having ≥3000 pigs enter the grower/finisher unit over a six-month period; diagnosis of Haemophilus (or Actinobacillus) in the past 12 months; and keeping pigs in the grower/finisher unit >120 days (as compared to <100 days). Not having a farrowing facility, mean weaning age <28 days, and <50% of finisher pigs on solid concrete only were associated with reporting ≥2% mortality attributed to respiratory problems.     

Energy expenditure in Awassi sheep grazing wheat stubble in the northern Negev Desert of Israel

In semi-arid Mediterranean areas, small grain aftermath stubble represents an important summer source of food for grazing flocks of small ruminants. Wheat stubble is a mediocre source of forage and flocks are grazed in summer under harsh conditions of temperature and air dustiness. However, stubble grazing procedures are changing, water and shading are more frequently available between grazing sessions (“improved management”), and the biological soundness of this ancestral practice needs to be re-visited. The present study was aimed at evaluating the cost in energy of “improved” wheat stubble grazing, compared with feeding a similar diet indoors. The intake of stubble was first quantitatively and qualitatively evaluated in Awassi sheep. Ewes consumed daily 980 ± 100 g day^− 1 of wheat stubble. Ewes were then housed and fed diets consisting of wheat hay, straw and grain formulated to be iso-energetic and iso-nitrogenous to diets consumed from wheat stubble. The average intake of ME was similar during the confinement and the pasture periods (6.4 ± 0.5 and 7.6 ± 0.8 MJ day^− 1of ME, respectively). During 2 days of each period, animals were fitted with external electrodes and data loggers of heart rate and skin temperature. Energy expenditure (EE) was calculated from oxygen consumption estimated as the product of heart beats rate measured for the two days by the amount of oxygen delivered to body tissues at each heart beat (O₂ pulse). The O₂ pulse was determined by simultaneously measurement of oxygen consumption and HR twice daily on two occasions, while grazing stubble and indoors. Energy expenditure and energy balance were not different in sheep while grazing wheat stubble (11.1 and − 3.5 MJ day^− 1) or fed indoors (11.1 and − 4.8 MJ day^− 1). Our data show that stubble did not cover nitrogen and energy requirements for maintenance, and that the cost of summer stubble grazing carried out under conditions described here is less than thought before.     

Hematology and clinical pathology of experimental Fascioloides magna infection in cattle and guinea pigs.

The hematologic and clinico-pathologic response to Fascioloides magna infection in cattle and guinea pigs was investigated. Twelve calves (six infected and six controls) were monitored for 26 weeks after inoculation with 1000 metacercariae. All calves remained healthy and there were no significant differences in weight gains between infected and control groups. Flukes (mean = 9.2, range 1–32) were recovered from the liver and abdominal cavity of all infected calves. The only significant response observed in the complete blood counts was an eosinophilia present in the infected calves extending from Weeks 2 to 26 post-infection. There were no significant differences in serum levels of aspartate aminotransferase and only minor increases in the levels of gamma-glutamyl transferase and sorbitol dehydrogenase.

A total of 48 infected and 48 control guinea pigs from three separate experiments were monitored for 16 weeks after inoculation with 20 metacercariae of Fascioloides magna. Infected guinea pigs died between 7 and 114 days after infection, and flukes (ean = 2.5, range 0–13) were recovered from the liver, abdominal cavity, lungs, thoracic cavity, skeletal muscle and subcutaneous tissue. There were no differences in weight gains between infected and control guinea pigs. Complete blood counts showed increases in white blood cell, monocyte and neutrophil counts from between the third and fourteenth weeks post-infection; however, the differences were not consistently significant. Infected guinea pigs developed a significant eosinophilia and basophilia from 2 to 16 weeks post-infection. There were no significant changes in the serum levels of alanine aminotransferase or gamma-glutamyl transferase. There was an increase in the serum levels of aspartate aminotransferase beginning at 5 weeks post-infection. The response observed in the guinea pigs was similar to that reported in sheep, suggesting the suitability of the guinea pig as a model for Fascioloides magna infection in the sheep.     

猪链球菌3型疫苗候选菌株筛选及3＋9型二价灭活疫苗对小鼠免疫效果评估

【目的】 筛选猪链球菌血清3型疫苗候选菌株,制备猪链球菌3＋9型二价灭活疫苗并评估其在BALB/c小鼠上的免疫保护效果。【方法】 从发病猪病料中分离猪链球菌血清3型菌株,通过蜡螟幼虫和BALB/c小鼠模型筛选出强毒株作为疫苗候选菌株,并对候选菌株进行生物学特性研究。将筛选得到的3型疫苗候选菌株和前期筛选的9型疫苗候选菌株灭活浓缩,使其抗原浓度为2×10¹⁰ CFU/mL,无菌检测后将浓缩抗原液按1：1配比混合,再混合抗原与Summit Poly Solution佐剂按4：1比例混合,制备猪链球菌3＋9型二价灭活疫苗,疫苗中猪链球菌血清3和9型含菌量均为2×10⁹ CFU/mL。将制备的疫苗免疫6周龄BALB/c小鼠,首免后第14天进行二免,二免后第14天进行攻毒。同时设立商品化疫苗免疫组和阴性对照组,评估疫苗的安全性和免疫保护效果。【结果】 PCR鉴定结果显示,23株临床分离株均为血清3型猪链球菌,依次命名为KQ3-1~KQ3-23。分别通过蜡螟和小鼠进行初筛和复筛,筛选到强毒株KQ3-1。毒力基因检测显示,该菌株基因型为gapdh^＋/sly^＋/fbps^-/orf2^-/mrp^-/89K^-/gdh^＋/epf^-;生长曲线显示,该菌株在37 ℃培养8~10 h时生长达到对数生长后期;BALB/c小鼠致病性结果显示,腹腔接种12 h内可引起小鼠精神萎靡、扎堆、毛发耸立、运动迟缓、死亡等临床症状,该菌株的LD₅₀为5.2×10⁷ CFU/只。制备的疫苗免疫小鼠后,小鼠精神状况、采食等均正常,疫苗注射部位无肿胀、硬块等不良反应,无死亡发生,表明该疫苗具有良好的安全性。免疫后进行猪链球菌血清2型菌株ZYS、猪链球菌血清3型菌株KQ3-1和猪链球菌血清9型菌株YT攻毒,对照组死亡率分别为90%、100%和100%,猪链球菌3＋9型二价灭活疫苗免疫组保护率分别为30%、80%和70%,商品化疫苗组的保护效果分别为70%、0和10%。【结论】 本研究研制的疫苗能对猪链球菌血清3和9型强毒株提供良好的免疫保护,该疫苗具备疫苗市场开发的潜在价值。     

Effects of cimaterol administration on plasma concentrations of various hormones and metabolites in friesian steers

The aim of the experiment was to determine the acute and chronic effects of the β-agonist, cimaterol, on plasma hormone and metabolite concentrations in steers. Twelve Friesian steers (liveweight = 488 ± 3 kg) were randomly assigned to receive either 0 (control; n=6) or .09 mg cimaterol/kg body weight/day (treated; n=6). Steers were fed grass silage ad libitum. Cimaterol, dissolved in 140 ml of acidified distilled water (pH 4.2), was administered orally at 1400 hr each d. After 13 d of treatment with cimaterol or vehicle (days 1 to 13), all animals were treated with vehicle for a further 7 d (days 14 to 20). On days 1, 13 and 20, blood samples were collected at 20 min-intervals for 4 hr before and 8 hr after cimaterol or vehicle dosing. All samples were assayed for growth hormone (GH) and insulin, while samples taken at −4, −2, 0, +2, +4, +6 and +8 hr relative to dosing were assayed for thyroxine (T₄), triiodothyronine (T₃), cortisol, urea, glucose and non-esterified fatty acids (NEFA). Samples taken at −3 and +3 hr relative to dosing were assayed for IGF-I only. On day 1, cimaterol acutely reduced (P<.05) GH and urea concentrations (7.6 vs 2.9 ± 1.4 ng/ml; and 6.0 vs 4.9 ± 0.45 mmol/l, respectively; mean control vs mean treated ± pooled standard error of difference), and increased (P<.05) NEFA, glucose and insulin concentrations (160 vs 276 ± 22 μmol/l, 4.1 vs 6.2 ± 0.15 mmol/l and 29.9 vs 179.7 ± 13.9 μU/ml, respectively). Plasma IGF-I, T₃, T₄ and cortisol concentrations were not altered by treatment. On day 13, cimaterol increased (P<.05) GH and NEFA concentrations (7.7 vs 14.5 ± 1.4 ng/ml and 202 vs 310 ± 22 mEq/l, respectively) and reduced (P<.05) plasma IGF-I concentrations (1296 vs 776 ± 227 ng/ml). Seven-d withdrawal of cimaterol (day 20) returned hormone and metabolite concentrations to control values. It is concluded that : 1) cimaterol acutely increased insulin, glucose and NEFA and decreased GH and urea concentrations, 2) cimaterol chronically increased GH and NEFA and decreased IGF-I concentrations, and 3) there was no residual effect of cimaterol following a 7-d withdrawal period.     

A study on the techniques used by untrained horses during loose jumping

Deterministic models¹ developed for the jumping horseindicated the important factors involved when jumping an obstacle². SVHS video recordings were obtained of 31 untrained horses (age: 3–5 years, height: 164.7±4.5 cm) jumping loose over a fence 1 m high by 0.5 m wide. The horses were designated to either a good group or a poor group based on a qualitative evaluation; good horses (n=18) cleared the fence with ease, and poor horses (n=13) consistently hit the fence. Video sequences were digitized to provide kinematic data on the horses' center of gravity (CG) and carpal and tarsal angles. Twenty kinematic variables were examined from the approach to the landing. Analysis of Variance (ANOVA) revealed significant between-group differences for the horizontal velocity of the last approach stride (Good: 5.77±0.80 m.s⁻¹; Poor: 6.42±0.95 m.s⁻¹; p=0.046). Significant differences were found in the relative carpal angles at take off (Leading limb: Good: 1.02±0.19 rad, Poor: 1.25±0.28 rad; p=0.010; Trailing limb: Good: 0.92±0.21 rad, Poor: 1.06±0.15 rad; p=0.046). The height of the CG over the center of the fence was also a significant variable that differed between the groups (Good: 1.83±0.08 m; Poor: 1.71±0.13 m; p=0.002). Finally the horizontal velocity of the landing was significant (Good: 5.26±0.92 m.s⁻¹; Poor: 6.27±0.84 m.s⁻¹; p=0.004) along with the angle of the CG to the ground at landing (Good: −0.45±0.08 rad; Poor: −0.38±0.07 rad). The velocity and CG variables which distinguished good and poor horses are likely to be strongly influenced by a rider; therefore, it is unlikely that these data alone could be used to predict elite jumping horses. The carpal angle data, however, may indicate a certain natural tendency by the young horses in the good group to keep their legs clear of the fence.