Comparison of plasma aldosterone concentration among clinical status groups of dogs with chronic heart failure

The plasma aldosterone concentration (PAC) among clinical status groups of 23 dogs with chronic heart failure was compared at various times after diagnosis of the problem. Eighteen dogs admitted in New York Heart Association (NYHA) class IV clinical status had significant elevations in PAC (P<0.0001), when compared with clinically normal dogs. Five dogs admitted in NYHA class III status and 4 dogs that responded with a change to NYHA class III status had significant elevations in PAC (P<0.01), when compared with clinically normal dogs. In patients with NYHA class IV status, the PAC was significantly greater (P<0.01) than in patients in NYHA class III status. For patients with the poorest prognosis, ie, severe signs of NYHA class IV status, the PAC was not markedly different, when compared with that for patients with a favorable prognosis, ie, recent onset of signs of NYHA class IV status. Patients treated with captopril had significantly lower PAC after therapy (P<0.01), whereas patients treated with hydralazine had significantly higher PAC (P<0.05) after therapy. It was concluded that heart failure in the dog increases PAC, most likely because of renin-angiotensin-aldosterone-system activation, and that the increase is related directly to the clinical status of the patient. Further, it was concluded that treatment of dogs in heart failure with captopril causes a decrease in circulating PAC, whereas treatment with hydralazine causes an increase in circulating PAC.     

Field trials with a bivalent vaccine (HVT and SB-1) against Marek's disease

White leghorn chickens on five farms were given a bivalent Marek's disease (MD) vaccine consisting of turkey herpesvirus (HVT) and SB-1 (a nononcogenic MD virus); other chickens received only HVT. The farms had histories of "vaccination failures," presumably owing to an exceptionally virulent challenge MD virus. The bivalent vaccine uniformly protected chickens better than HVT alone between 12 and 16-20 weeks of age, when serious MD losses occurred. During that period, total mortality in groups given both viruses ranged from 0.39 to 1.26% (mean 0.86%), whereas that in HVT-vaccinated groups not exposed to SB-1 varied from 1.92 to 7.44% (mean 3.43%). Chickens in pens or rows with close contact to those given bivalent vaccine also had low MD mortality rates (0.46-1.06%, mean 0.77%), probably from the spread of SB-1.     

Raised environmental temperature and food rationing as means of restricting growth of the replacement pullet

1. Four rearing temperature regimes (15, 20, 25, 30 °C) and three feeding schedules (ad libitum, restricting to the ad libitum intake of the 12th week and feeding 70% of this rate) were carried out with layer replacement pullets to 170 d of age. From this age, during lay, birds were kept at either 21 °C or on a 24‐h cycle of 21 for 18 h and 28 °C for the 6 h before lights out. Both a white and a brown egg‐laying strain were used.

2. Body weight at 169 d of age varied from, on average, 1409 g (15 °C, ad libitum) to 943 g (30 °C, 70% schedule) for the white strain and 1947 to 1250 g for the same treatments respectively for the brown strain. Sexual maturity was considerably delayed by the 70% feeding schedule, only slightly by rearing at 30 °C.

3. Rearing at 30 °C tended to depress subsequent egg output. The 70% feeding schedule at least maintained egg output compared with birds fed ad libitum in rearing.

4. There was a highly significant effect of temperature treatment during lay on food intake. The reduction in food intake due to the 21–28 °C cycle, however, appeared small.     

The activities of amylase and a trypsin‐like protease in the gut contents of germ‐free and conventional chickens

1. Proteolytic and amylase activities were assayed in the gut contents of germ‐free and conventional chickens aged 3 and 14 d.

2. The tendency was for the proteolytic activity to be increased and the amylase activity to be decreased in conventional chicks. These differences were statistically significant in the caecum.

3. All of the additional proteolytic activity detectable in the caecum of conventional chicks was inhibited by soyabean trypsin inhibitor. However, the increased activity was not detectable in the small intestine and was, therefore, not due to pancreatic trypsin.

4. Attempts to demonstrate in vitro bacterial production of a trypsin‐like enzyme were unsuccessful.     

A note on the structure and iron‐binding properties of egg‐shell membranes

1. When a solution of ferric ammonium sulphate was added to shell membranes of the domestic fowl, iron infiltrated the mantle (cortex) surrounding the cores of the individual fibres of the membranes.

2. Contraction of warm eggs in ice‐cold colloidal iron caused flooding of pore canals and contamination of the underlying shell membranes with this element.

3. Appreciable contamination of the inner shell membrane with iron persisted for 25 d in infertile eggs stored at 37.5 °C.     

A note on changes in egg‐shell porosity with flock age and season during the first breeding cycle of domestic ducks

1. — Changes in egg weight and egg‐shell porosity with flock age and season are presented for domestic duck flocks in their first laying cycle.

2. — The first eggs laid are of low weight and shell porosity but generally by the fifth week of lay both characteristics have increased to the values found in the mature flock.

3. —For mature flocks porosity decreases in the summer and the consequences of this are considered in relation to the observed decrease in hatch‐ability at this time.     

Effects of lauryl sulphate on egg‐shell quality in laying hens

1. The effect of feeding the detergent, sodium lauryl sulphate at concentrations up to 10 g/kg diet on egg‐shell quality was examined in laying hens at 24, 36 and 48 weeks of age.

2. Lauryl sulphate at 2.5 g/kg or more in the diet significantly increased shell breaking strength, shell thickness and shell weight at 24 and 36 weeks. In 48‐week‐old hens only shell breaking strength was increased significantly. Egg production and egg weight were not affected significantly by lauryl sulphate.

3. Lauryl sulphate might increase these measures of quality by increasing shell deposition and/or shell elasticity.