Bovine Cryptosporidiosis: Clinical and Pathological Findings in Forty-two Scouring Neonatal Calves

Cryptosporidia organisms were identified in 42 of 161 (26%) neonatal, diarrheic calves, over a 32 month period commencing July 1979. Forty of the 161 calves were submitted alive and cryptosporidiosis was diagnosed in 63% (25 of 40) of them. The cryptosporidia infected calves were usually one to two weeks old and came from 26 herds where the typical history was profuse, watery diarrhea in nearly all neonatal calves. The diarrhea usually started around one week of age, was unresponsive to all conventional antidiarrhea therapies, lasted for two or more weeks and was usually fatal. Twenty-nine (69%) of the cryptosporidia infected calves were submitted between December and February. These calves were often hutch reared.

Histopatholoical examination revealed large numbers of the coccidial parasite Cryptosporidium sp embedded in the microvilli of jejunal and ileal absorptive enterocytes of all affected calves. The organisms were identified as trophozoites and schizonts (asexual stages) and macrogametes (female sexual stages) with the electron microscope. Microgametes (male sexual stages) were not identified. Occasionally a merozoite (asexual stage) was also seen apparently burrowing into or about to be enveloped by a host microvillus. Observation of the organisms was much easier when diarrheic calves were submitted alive. Enterotoxigenic Escherichia coli were often cultured from intestines of dead calves and occasionally from calves submitted alive. Coronavirus particles were seen in one calf. In the last year of this study, oocysts were identified in fecal smears stained with May-Grünwald-Giemsa stain and fecal samples using a dichromate solution flotation technique.

     

A note on the amino acid composition of the Turkey

1. The amino acid composition of the whole body protein of 28‐ and 56‐d‐old turkeys is reported.

2. There were some differences between the two ages; these could largely be reconciled by considering the likely differences in the proportion of feather protein.

3. The results were compared with similar values for the chicken and goose; overall there is a striking similarity, both in absolute concentrations and relative proportions of amino acids.     

Influence of ascorbic acid on the adverse effect of feeding a diet containing excess tyrosine to chicks

1. The effects of dietary or parenteral administration of ascorbic acid on the adverse effects of excess dietary tyrosine were investigated with young male White Leghorn chicks in a 2‐week experiment.

2. Addition of 10 g ascorbic acid/kg to the control diet (without excess tyrosine) produced no beneficial effects on performance. Excess dietary tyrosine caused depressions in all measures of performance.

3. Adding 0.1, 1, 10 or 20 g ascorbic acid/kg to the diet containing excess tyrosine tended to improve performance.

4. Subcutaneous injection of 50 mg ascorbic acid/bird d to chicks receiving excess tyrosine brought about a significant improvement in body‐weight gain.

5. The elevation of plasma free tyrosine caused by excess dietary tyrosine decreased as dietary ascorbic acid increased.

6. Ascorbic acid can alleviate, though not completely counteract, the adverse effect of excess dietary tyrosine.     

Scanning electron microscope study of the feather follicle wall attachment in chickens

1. A scanning electron microscope study showed indentations by the follicle wall cells into the feather shaft. In other areas altered cells or keratinised cell fragments form bridges which join the feather to the follicle.

2. In the early stage of growth the feather shaft is held in place by cell indentations, whereas later, bridges are seen which probably hold the feather more firmly.     

Book reviews

Research and Development in Relation to Farm Animal Welfare, contributions by B. A. Baldwin, J. R. Bareham, I. J. H. Duncan, R. Ewbank, D. C. Hardwick and K. Vestergaard, Animal Management, 11, Series Edited by D. W. Fölsch. Birkhauser Verlag, Basel, 1981. ISBN‐3–7643–1241–6.

First European Symposium on Poultry Welfare. Edited by L. Yding S0RENSEN. Published by the Danish Branch of World's Poultry Science Association. 1981. 238pp. D.Kr.90. ISBN 87–88162–00–1.     

The relationship between plasma triglyceride concentrations and body fat content in male and female broilers—a basis for selection?

1. The relationship between plasma triglyceride concentrations and body fat content was examined in three groups of male and one of female broiler chickens fed ad libitum on a normal growing diet.

2. Phenotypic correlations between total plasma triglyceride concentration and fat content were + 0.50, + 0.37 and + 0.39 for the three groups of male broilers and +0.33 for the group of females. Triglyceride content of plasma very low density lipoprotein (VLDL) plus low density lipoprotein (LDL) showed similar correlations with fat content.

3. Selection of birds from a flock of 550 male broilers on the basis of high or low plasma VLDL plus LDL triglyceride concentrations produced groups with significant differences in body fat content but little difference in body weight.

4. The results suggest that measurements of plasma triglyceride concentration could be used as an indirect means of selecting for decreased body fat content in broiler breeding programmes.     

Relationship between energy and protein intakes and laying characteristics in individually‐caged broiler breeder hens

1. Individually‐caged broiler hens, which had been reared on an advised rationing programme, were fed allowances of 1.88, 1.61, 1.32 or 1.13 MJ apparent metabolisable energy/bird d at four different protein intakes (27, 23, 19.5 or 16.5 g crude protein per bird d) from 21 to 60 weeks of age.

2. Age at first egg, body‐weight gain and egg production were affected by energy allowance. Birds on the lower energy allowances came into lay later than birds on the higher energy allowances and at a lower body weight.

3. Body‐weight gain decreased with decreasing energy allowance. The decrease in egg output in response to decreasing energy allowance resulted from more birds ceasing to lay and fewer birds laying on more than 3 d per week. Similar changes in the distribution of rates of lay were observed on each treatment as the flock aged.

4. The relationship between body‐weight gain and egg number on each treatment was negative from 21 to 36 weeks, but became less consistent with age.

5. Protein intake had little effect on body weight. At the lowest energy allowance, egg number and egg weight decreased with increasing protein allowance. This effect was not observed on the higher energy allowances.     

Effect of injecting amino acids into the egg on embryonic and subsequent growth in the domestic fowl

1. The growing embryo uses about 1% of the total protein available in the egg during the first week of incubation.

2. Injecting the growing embryo with amino acids equivalent to the amount of protein used resulted in higher weight of chicks at all stages up to 56 d.