The effects of continuous and rotational grazing of sourveld on the quality of herbage selected by Simmentaler heifers

A grazing trial was conducted at the Kokstad Agricultural Station to compare the dry matter digestibility (DMD) and crude protein content (CP) of diets selected by four fistulated cattle which were continuously and rotationally grazing sourveld. Two stocking rates of 1,0 and 2,3 animals/ha (0,5 and 1,2 LSU/ha) were applied under each grazing method. The mean DMD and CP values of diets selected in the continuous and rotational grazing treatments, respectively, were: DMD=64,3%, 62,3%; CP=6,63%, 6,88%. The effect of stocking rate on the quality of the diet selected varied between the two grazing methods. DMD and CP of diets selected under rotational grazing decreased with time during the week‐long period of stay in each paddock. On average, DMD and CP values on the first and sixth day respectively, were: DMD=66,6%, 60,5%; CP=8,37%, 6,01%. These differences were more pronounced at the higher than at the lower stocking rate. It was concluded that, although some of the treatment differences were small, grazing method differences in the DMD of diets might at least partially account for observed differences in livemass gains under the two grazing systems.     

Influence of varying dietary electrolyte balance on broiler performance under tropical summer conditions

A 6‐week feeding trial was conducted to determine the effects of varying dietary electrolyte balance (DEB) on growth performance and physiological responses in broiler chicks reared during hot summer months (26.1–37.5 °C). The average minimum and maximum room temperatures recorded from 14 to 42 days of age were 26.1 and 37.5 °C, respectively, with relative humidity ranging from 51% to 55%. Five DEB treatments supplying 0, 50, 150, 250 and 350 (Na⁺+K⁺–Cl^?) mEq/kg of diet were prepared by adding NaHCO₃ and/or NH₄Cl to basal diet that contained 185 mEq/kg from 1 to 28 days and 172 mEq/kg from 29 to 42 days. These DEB diets were randomly offered to six experimental units of 20 chicks each. Improved 42‐day body weight gain (BWG), feed:gain (F:G) and reduced mortality was noted with DEB 50, 150 and 250 mEq/kg compared to DEB 0 and 350 mEq/kg. A quadratic effect of increasing DEB level was observed on BWG and F:G, whereas the effect was linear for feed intake, water intake and litter moisture. The DEB 50, 150 and 250 maintained better blood pH, pCO₂ and HCO₃ concentrations during acute heat stress periods than that of 0 and 350. The blood heterophil and lymphocyte percent as well as heterophil:lymphocyte were remained unaffected. The lowest DEB (0 mEq/kg) diet reduced the feed intake and promoted metabolic acidosis. At 350 mEq/kg DEB, water intake and metabolic alkalosis were promoted probably due to high levels of dietary NaHCO₃. The study concluded that overall better performance was recorded with DEB 50, 150 and 250 mEq/kg. These results indicated that single optimal DEB value could not be recommended to combat heat stress in broilers.     

中国生猪健康养殖业发展的战略思考

作者在分析生猪健康养殖业发展背景的基础上,以实现动物健康、人类健康、环境健康、产业链健康为目的,从质量保障和价值保障2个方面构建了生猪健康业发展的目标体系及其实现途径,重点从技术体系、组织结构、运行机制、适度规模等方面提出了生猪健康养殖业发展的保障策略。     

Use of topical selamectin for the treatment of Trichosomoides crassicauda infection in laboratory rats

The present study investigated the efficacy of topical selamectin for elimination of naturally acquired Trichosomoides crassicauda infection in rats. Twelve T. crassicauda-positive rats were assigned to the treatment group and six rats were assigned to the control group. Selamectin (6 mg/kg) was applied topically to the skin in a single spot at the base of the neck in front of the scapulae in the treatment group. To assess the efficacy of the treatment, animal faeces were investigated with the use of the flotation technique on days 0, 4, 14 and 24 after selamectin application. The rats of the treatment and control groups were necropsied on the day 24. In the treatment group, 7 of 12 infected rats were cured completely. Topical selamectin was found to be effective in eliminating T. crassicauda infection in rats.     

The risk of death: the confidential enquiry into perioperative small animal fatalities

Objective To estimate the risks of anaesthetic and sedation‐related mortality in companion animals in the UK. (The Confidential Enquiry into Perioperative Small Animal Fatalities, CEPSAF). Study design A prospective cohort study with nested case–control study. Animal population All small animals anaesthetized and sedated at participating centres between June 2002 and June 2004. Methods Patient outcomes at 48 hours (alive, dead and killed) were recorded. Anaesthetic and sedation‐related death was defined as death where surgical or pre‐existing medical causes did not solely cause death. Species‐specific risks of anaesthetic‐related death and 95% confidence intervals (95% CI) were calculated. Risks were also estimated in the sub‐sets of dogs, cats and rabbits that were either healthy or sick (ASA 1–2 and 3–5, respectively). Results One hundred and seventeen veterinary practices participated in the study and 98 036 dogs, 79 178 cats and 8209 rabbits were anaesthetized and sedated. Overall risks of anaesthetic and sedation‐related death in dogs were 0.17% (1 in 601, 95% CI 0.14–0.19%), in cats 0.24% (1 in 419, 95% CI 0.20–0.27%) and in rabbits 1.39% (1 in 72, 95% CI 1.14–1.64%) within 48 hours of the procedure. In healthy dogs, cats and rabbits, the risks were estimated to be 0.05% (1 in 1849, 95% CI 0.04–0.07%), 0.11%, (1 in 895, 95% CI 0.09–0.14%) and 0.73% (1 in 137, 95% CI 0.54–0.93%), respectively. In sick dogs, cats and rabbits, the risks were 1.33%, (1 in 75, 95% CI 1.07–1.60%), 1.40% (1 in 71, 95% CI 1.12–1.68%) and 7.37% (1 in 14, 95% CI 5.20–9.54%), respectively. Postoperative deaths accounted for 47% of deaths in dogs, 61% in cats and 64% in rabbits. Most other small animal species had higher mortality risks. Conclusions and clinical relevance Small animal anaesthesia appears to be increasingly safe. Greater patient care in the postoperative period could reduce fatalities.     

A multicentric retrospective study of serum/plasma urea and creatinine concentrations in dogs using univariate and multivariate decision rules to evaluate diagnostic efficiency

BACKGROUND: Urea and creatinine are the most frequently used indirect markers in plasma and serum of glomerular filtration rate in dogs. Both have been shown to lack sensitivity but their diagnostic efficiency for the diagnosis of kidney disease has been minimally investigated. OBJECTIVE: The purpose of this retrospective study was to investigate the influence of possible factors of variation on both analytes and to determine whether specific decision rules should be drawn up for subpopulations of dogs. METHODS: The results of urea and creatinine measurements, breed, sex, age, and health status (healthy, renal disease, or nonrenal disease) of 3822 dogs were collected from the archives of 5 veterinary clinics. Data were analyzed with univariate and multivariate decision rules with and without adjustment. RESULTS: There were significant effects and interactions of almost all of the sources of variation. Slight improvements in diagnostic efficiency were obtained by adjusting the decision rules to these sources of variations. Univariate decision rules gave approximately the same diagnostic efficiency for urea and creatinine concentrations, with sensitivity and specificity in the range of 70% and 90%, respectively, using the upper limit of the reference interval as the threshold value. Multivariate decision rules provided only minor improvements in diagnostic efficiency. CONCLUSION: Simultaneous measurement of both urea and creatinine is of limited diagnostic value over the analysis of a single variable. Creatinine is the preferred analyte as it is affected by fewer extrarenal factors of variation.     

Chlamydophila psittaci infections in humans during an outbreak of psittacosis from poultry in Germany

In 2005, an outbreak of severe respiratory disease in a mixed poultry flock that was infected with Chlamydophila (C.) psittaci led to dissemination of the infection to at least 100 small poultry farms in 11 districts of Central Germany. At the same time, a total of 24 persons in contact with poultry from one of the flocks reported flu-like symptoms to their physician, thus suggesting zoonotic transmission. Within 3 weeks, seven individuals had to be hospitalized, with three of them requiring intensive care. Analysis of ompA sequences from chlamydial isolates and directly from clinical samples revealed the presence of both genotype A and E/B of C. psittaci at the source of the outbreak and in contact flocks. Genotype A was also detected in the three severely ill patients. The findings of the present study demonstrate the high zoonotic potential of avian chlamydiae. To ensure speedy eradication of psittacosis in poultry flocks and effective treatment of infected humans, fast, sensitive and species-specific detection of the causative agent is essential, as well as close collaboration between regional public health services, attending physicians and the diagnostic laboratories involved.     

Measurement of ileal protein digestibility using 15N-labeled rats

After 15N-labelling over 7 days male albino rats (92-95 g live weight) received either a wheat or whole egg diet (10 animals each) for 4 days. On the following day of the experiment 5 animals each continued to receive their diets as their morning meal (group 1 whole egg, group 3 wheat) and 5 animals each after the previous feeding of a wheat diet received a 2.9 g whole egg diet (group 2) and after the previous feeding of a whole egg diet a 2.85 g wheat diet (group 4) resp. This morning meal was supplemented with chromium(III)oxide. The rats consumed their meals within 20 minutes. The animals were killed 3.5 hours after the beginning of feed intake. At that time the following relative amounts (in % of the intake) could be detected in the stomach in the sequence of groups 1 to 4: Cr2O3 = 22.5; 26.5; 57.5 and 64.2; dry matter = 25.4; 22.1; 43.2 and 38.5. The better agreement between the whole egg diet and Cr2O3 can be explained with the hydrophobic qualities of Cr2O3 and the small disposition of the Cr2O3 to decompose in combination with the whole egg diet. In the first third of the small intestines less than 1% of the intake of Cr2O3 and a maximum of 3.5% of the DM could be detected. Between 20 and 36% of the Cr2O3 and between 15 and 20% of the dry matter intake were ascertained in the small intestines as a whole; in the large intestines the values were 12-20% of the Cr2O3 and 16-23% of the DM. Endogenous 15N-secretion could be ascertained in all parts of the digestive tract. According to the method suggested by U. Bergner and H. Bergner (1982), protein digestibility in the last third of the small intestines was calculated as follows: (formula; see text) The following ileal digestibility values were calculated for crude protein: whole egg = 95.6%; whole egg (wheat previously) = 95.5%; wheat = 94.1%; wheat (whole egg previously) = 85.1%. It is a precondition for the application of this method that at the time of killing representative quotas of the diet sample to be tested can be detected both in the stomach and the large intestine so that the decrease of 15N-labelling in the ileum is actually caused by the test protein.     

Determining of nitrogen absorption and nitrogen secretion in different sections of the pig's intestine by digesta exchange between 15N labelled and unlabelled animals

In an experiment with 3 pigs (initial live weight 30 kg, each fitted with 2 re-entrant fistulas in duodenum and ileum, one labelled with 15N), the duodenal and ileum digesta was exchanged. The N and 15N contents were estimated in faeces, urine, duodenal and ileum digesta of all experimental animals as well as in special organs and in the contents of different tract sections. The 15N excess (15N') of N compounds secreted into the gut lumen was determined using the 15N' in pancreas, gut mucosa and TCA-soluble blood serum. From measuring the digesta passage through the 3 sections of the digestive tract: 1. mouth ... duodenum, 2. duodenum ... ileum, 3. ileum ... after (Krawielitzki et al., 1989) the absorption and secretion rates of nitrogen were calculated. Secretion into the 1st section amounted to 5.3 g N/d (= 15% of intake) and the absorption to approximately 1% of intake. In the 2nd section the corresponding dates were 8.9 resp. 38.6 g N/d (= 25 resp. 110% of N intake), and in the 3rd one 1.9 resp. 8.4 g N/d (= 5.6 resp. 24% of N intake). Total absorption amounted to 134% of N intake and the over all re-absorption of endogenous N compounds secreted into the gut lumen to about 90%. During the passage the amount of endogenous N (g/d) decreased from 5.3 at the duodenum to 3.8 at the ileum to 1.6 in the faeces, but the relative portion increased (13 resp. 35 resp. 39%). An incorporation into body proteins occurred only from N compounds absorbed in the 1st and in the 2nd section. N (or 15N) absorbed in the large intestine was almost quantitatively excreted by urine. The method of digesta exchange between cannulated labelled and unlabelled pigs seems to be a suitable method to estimate absorption and secretion of exogenous and endogenous N portions in various sections of the digestive tract.