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.     

Gastrointestinal colonization by salmonellae and pathogenic Escherichia coli in monoxenic and holoxenic chicks and poults

Chicks monocolonized by either salmonellae or pathogenic strains of Escherichia coli had persistent and undiminished colonization of all levels of the gastrointestinal tract and frequently had bacteremia during test periods ranging to 35 days. Poults monocolonized by salmonellae or Arizona hinshawii 7:"1,7,8 developed a similar pattern of colonization. Conventionally reared chicks and poults had rather variable colonization by these pathogens, and it was most persistent in the ceca. Groups treated with a native protective microflora were infrequently colonized. Differences in colonization are explainable by lack of competing bacteria in the monocolonized group and by various degrees of protection provided by microflora colonizing the other groups.     

Oat cells in the pathology of ovine pneumonia-pleurisy

Light microscope observations on oat cells in the ovine pneumonia-pleurisy complex are presented. This study is based on the experimental production of the disease by viruses and Pasteurella haemolytica. Oat cells appeared only in necrotic lesions associated with large numbers of P. haemolytica in the pneumonic lung. It is suggested that oat cells originate from blood monocytes, which transform into the oat shape when developing in the necrotic, hypoxic environment created by P. haemolytica. They were not, however, observed to be phagocytic. Oat cells are characteristic of pneumonic pasteurellosis but are not pathognomonic because they can also be found in extrapulmonary locations and in other pathological conditions of the lungs.     

Selenium deficiency, the drug metabolising enzymes and mycotoxicoses in sheep

An examination was made of the relationship in Romney sheep between selenium deficiency and (i) the state of the liver drug metabolising enzyme system, (ii) subclinical liver damage, (iii) susceptibility to facial eczema, and (iv) susceptibility to ryegrasss staggers. The microsomal electron transport detoxifying enzymes based on cytochrome P-450 were unaffected by Se deficiency, suggesting that these enzymes are uninduced on ryegrass/clover pastures. Selenium deficiency had no effect on sporidesmin-induced liver damage, which makes it unlikely that peroxidative events countered by Se-dependent glutathione peroxidase (E.C.1.11.10) have a major role in the mechanism of sporidesmin toxicity. Selenium deficiency did appear to suppress the development of photosensitisation. There was no major effect on ryegrass staggers and no deficiency-induced subclinical liver damage.     

Stimulation of the titre of a sheep serum factor that is related to the sheep complement system

Serum from most sheep subjected to a single jugular bleeding, repeated bleeding or an intraperitoneal injection of yeast and repeated bleeding, showed an increase in the titre of a serum component called serum factor. Serum factor reached a peak titre 2 to 5 days after treatment started. For some sheep, the titre was elevated for a 9- to 12-day period whereas for others the titre dropped markedly on day 7 followed by a rise on day 9. Serum factor reacts with sheep erythrocytes sensitised with rabbit antibody (sheep E-rabbit A). Serum factor can be detected on sheep E-rabbit A using guinea-pig antiserum that reacts with sheep complement (C). Serum factor is inactivated by heating at 56 degrees C for 30 minutes, but is only partially inactivated at 50 degrees C for 30 minutes. The reaction of serum factor with sheep E-rabbit A is inhibited by chelators of Ca++ and/or Mg++. Serum factor appears to be related to the sheep C system. Preliminary results suggest it may he a component of the classical pathway of sheep C, possibly the second component, C2.     

Epidemiology of leptospirosis in dairy farm workers in the Manawatu. Part II. A case-control study of high and low risk farms

Subsequent to a cross-sectional serological survey of Manawatu dairy farm workers, a case-control study was carried out to investigate the correlation between titres to leptospiral serovars in workers and those in cattle in their herds. A total of 52 herds was investigated, 25 of which were high risk where milkers had titres of 1:96 or greater, and 27 were case-controls where milkers had no detectable agglutinin titres at a minimum serum dilution of 1:24. The serological prevalence of titres to hardjo in cattle on high risk farms (76.5%) was significantly higher (P<0.05) than on the case-control farms (60.0%). The geometric mean titres of seropositive cattle on high risk farms were also significantly higher (P<0.01) than in the cattle from the case-control farms, especially in the younger cohorts. These findings suggest that there was active endemic hardjo infection in the two- to three-year-old cattle on the high risk farms. Titres to pomona were demonstrated in only 5.2% of the cattle from both types of farm. Workers with titres to pomona tended to be from farms on which stock, especially calves, were bought-in and pigs were kept. Conventional measures for protecting milkers from contact with infected urine appeared to be ineffective and it is concluded that prevention of leptospirosis in dairy farm workers can only be achieved by elimination of infection in the herd by vaccination of cattle.     

Chemical control of Botrytis cinerea and Sclerotinia sclerotiorum on dwarf snap beans

Two sprays of vinclozolin (0.5 kg a.i. ha^–1) or procymidone (0.5 kg a.i. ha^–1), the first at the beginning of flowering and the second two weeks later, gave the best control ofBotrytis cinerea on dwarf snap beans (Phaseolus vulgaris). Good results were also obtained with iprodione and with thiophanate-methyl. Vinclozolin and procymidone at the same program were the most active fungicides againstSclerotinia sclerotiorum. Treatments with the latter two fungicides resulted in increased yields of pods and had no influence on colour and quality of the pods. Residue levels were below the tolerances.Samenvatting Twee bespuitingen met vinchlozolin (0,5 kg a.i. ha^–1) of procymidon (0,5 kg a.i. ha^–1), de eerste in het stadium begin bloei en de tweede 14 dagen later tijdens de peulzetting, waren voldoende omB. cinerea in stamslabonen te bestrijden. Tevens werden goede resultaten verkregen met iprodion en thiofanaat-methyl. Vinchlozolin en procymidon gaven volgens hetzelfde schema toegepast ook de beste werking tegenS. sclerotiorum. Toepassingen van deze laatste twee fungiciden leverden een hogere peulopbrengst en hadden geen invloed op de kleur en de kwaliteit van de peulen. Het residugehalte in de peulen lag beneden de toelaatbare grens.This research was subsidized by the Instituut tot Aanmoediging van het Wetenschappelijk Onderzoek in Nijverheid en Landbouw (IWONL).     

Radiographic changes in the lungs of horses with exercise-induced epistaxis

This paper describes the distinctive radiographic changes detected in the dorso-caudal lungfields of four racing thoroughbreds recently affected by exercise-induced epistaxis. A diffuse but localized increase in density was seen in all four cases, which demonstrated a variation from a predominantly alveolar density to an interstitial pattern and finally to increased bronchial markings. Evolution of the radiographic pattern of the pulmonary densities appeared to be related to the time that had elapsed since the bleeding incident. The implications of the changing pattern and site of the densities are discussed.