Observations on the use of feeding space in a commercial broiler chicken house

1. Observations were made on the use of food pans and food trays by commercially grown broiler chickens.

2. Birds fed by going inside the feeders on top of the food or from standing around the outside of the feeders. The feeding times of birds inside feeders were significantly longer than those of birds outside. Different reasons to account for this are proposed for the 2 types of feeder.

3. The total number of birds able to feed together from a tray or pan changed as the birds grew. With trays this change in the number of birds was a steady decline. With pans the change was non‐linear and reflected a changing ratio of birds eating in to birds eating out. This ratio was influenced by pan design features and by competition for feeding space.

4. The data suggest that a linear measure of feeding space, as used in research trials and Codes of Practice for Welfare, does not adequately describe birds’ access to and use of feeding space. Implications for both research and the commercial industry are discussed.     

The detection of Mycobacterium paratuberculosis in bovine faeces by isolation and the comparison of isolation with the examination of stained smears by light microscopy

The detection of Mycobacterium paratuberculosis organisms in bovine faeces by isolation was compared with that by the microscopical examination of Ziehl-Neelsen stained faecal smears for the presence of clumps of acid-fast M. paratuberculosis organisms. Faeces were obtained from cattle naturally or experimentally infected with M. paratuberculosis as well as from uninfected cattle. Microscopical examination was an unreliable method for the detection of M. paratuberculosis organisms, since the organisms were only detected in 99 (=55.9%) of 177 culturally positive faecal samples. 1111 addition, clumps of acid-fast organisms indistinguishable from M. paratuberculosis were also observed iin three of 18 samples from cattle free from Johne's disease and in 18 of 37 culturally negative samples from paratuberculous cattle. When M. paratuberculosis organisms were added to faeces from an uninfected cow, results showed that isolation attempts should be positive when 15 or more M. paratuberculosis organisms per gram of faeces are present.     

实验性流行性腹泻仔猪小肠粘膜上皮细胞及肠系膜淋巴结的超微结构

给8头生后3d的哺乳仔猪经口感染猪流行性腹泻病毒(PEDV)“吉”毒株,于感染后18、30、45和96h各扑杀2头,以透射电镜和扫描电镜观察了小肠粘膜上皮细胞及肠系膜淋巴结的超微结构。结果表明,小肠上皮细胞的病变因感染时间不同而有明显差异。上皮细胞的脱落和残留上皮细胞超微结构的破坏,以感染后30h最严重,病毒在这些上皮细胞内的增殖最显著。感染后45h,见有大量新生上皮细胞修补损伤的肠绒毛。感染后96h,小肠绒毛短缩、粗大乃至发生融合。实验仔猪肠系膜淋巴结内巨噬细胞和淋巴细胞的超微结构均遭到破坏,在巨噬细胞内见有PED冠状病毒粒子。     

Platelet activating factor as a mediator of equine cell locomotion

Equine polymorphonuclear (PMN) and mononuclear (MN) leucocytes were separated on Percoll gradients and used to study the chemoattractant properties of the polar ether-linked phospholipid, platelet activating factor (PAF). Six concentrations of PAF ranging from 1 ng/ml to 100 g/ml were studied in each of two in vitro assay systems, the agarose microdroplet and a microfilter technique. Very significant (p<0.01) increases in the movement of both PMN and MN cells were obtained with most concentrations of PAF. In two instances there was no apparent concentration-response relationship, although the action of PAF was approximately bell-shaped in two others. The possible significance of these findings for equine inflammatory conditions is discussed.     

Escherichia coli sepsis and endotoxemia in conscious young pigs

In conscious pigs the influence of intravenous infusion of live E. coli (7×10⁸/kg), of the equivalent amount of endotoxin (20 g/kg) or of a high dose of endotoxin (2.5 mg/kg) on the hemodynamic, clinical and pathological parameters and on survival rate was studied. E. coli and endotoxin infusion resulted in pulmonary hypertension, systemic arterial hypotension, a decrease in cardiac output and an increase in heart rate. Clinical signs were characterized by respiratory and nervous disturbances, whereas necropsy revealed hemorrhages and edema in several organs. Although these findings were similar in the three groups, a marked difference in lethality was observed. Infusion of E. coli or of the high dose of endotoxin resulted in a significant mortality, whereas all pigs survived the infusion of the low dose of endotoxin. This suggests that the lethal pathophysiological mechanisms may only become activated when a sufficient amount of endotoxin is released into the circulation.     

Serum bile acids: reference values in healthy dogs and comparison of two kit methods

Serum bile acid (SBA) reference intervals were established by use of a radioimmunoassay method for fasting dogs to be 0.2 to 4.3 micro mol/L (n = 60) and for 2 hour postprandial samples to be 0.6 to 24.2 micro mol/L (n = 37). The SBA reference intervals estimated using an enzymatic method were 0 to 8.6 micro mol/L for fasting (n = 26) and 0 to 29.8 micro mol/L for 2 hour postprandial samples (n = 36). The correlation between the two methods including samples from healthy dogs and clinical cases is good (n = 128, r = 0.82, p < 0.0001). The radioimmunoassay method is linear to 50 micro mol/L and the enzymatic method is linear to 100 micro mol/L, thus both methods require serum dilutions to be made in many cases of primary liver disease. The enzymatic method is less expensive and more convenient for use in a clinical laboratory but requires a greater sample volume (400 micro I) than the RIA method (50 micro I). Both methods have adequate precision and accuracy to be useful as diagnostic tests of liver function in dogs.     

Bovine and canine acute phase proteins

Acute phase proteins are serum proteins which increase in concentration during the acute phase response to inflammation or infection. The response occurs in all animals, but in different species the response of individual proteins can be significantly different. Of the numerous acute phase proteins which have been identified in humans, a number have been examined in cattle and dogs but usually on an individual basis with little reference to their part in the acute phase response. Biochemical, physiological and clinical investigations into haptoglobin, fibrinogen, ₁-proteinase inhibitor, ceruloplasmin, seromucoid and C-reactive protein of cattle and dogs have therefore been reviewed with the emphasis on their role in this response to tissue damage.