Air hygiene in a broiler house: comparison of deep litter with raised netting floors

1. Deep litter and raised netting flooring systems in broiler houses were compared for their effects on air quality and bird health during an 8-week growing period. 2. Weekly measurements were taken of respirable dust, numbers of airborne microorganisms and concentrations of gaseous pollutants. Airborne fungi and bacteria were identified to species. 3. At the end of the experimental period, randomly sampled bird lungs were examined for the presence of viable microorganisms and for pathological changes. Bird health and performance were monitored throughout the 8 weeks. 4. Respirable dust concentrations and numbers of airborne microorganisms were significantly higher in the litter rooms. The type of floor had no effect on concentrations of gaseous ammonia. 5. Floor type had no significant effect on bird mortality but birds on litter had a slightly better gain:food ratio. However, birds on litter were observed to have a higher incidence of lung damage and more of the birds on litter had viable microorganisms present in the lungs at necropsy.     

Differences between primiparous and multiparous dairy cows in the inter-relationships between metabolic traits, milk yield and body condition score in the periparturient period

During the early postpartum period dairy cows mobilize fat and muscle to support lactation. This is associated with alterations in blood metabolite and hormone profiles which in turn influence milk yield and fertility. This study developed models to determine how metabolic traits, milk yield and body condition score were inter-related at different times in the periparturient period and to compare these relationships in primiparous (PP, n=188) and multiparous (MP, n=312) cows. Data from four previous studies which included information on blood metabolic parameters, parity, milk yield, body condition score and diet were collated into a single dataset. Coefficients of polynomial equations were calculated for each trait between -1 week pre-calving and week +7 postpartum using residual maximum likelihood modelling. The completed dataset was used in a multiple correlation model to determine how the best fit curves were related to each other over time. PP cows had higher concentrations of insulin-like growth factor-I and lower beta-hydroxybutyrate concentrations throughout, higher leptin concentrations pre-partum and both the peak in non-esterified fatty acids and the nadir in urea concentration occurred earlier after calving. These differences were associated with significantly lower milk production. Leptin concentrations fell at calving and were related to body condition score. Insulin was negatively correlated with yield in MP cows only. In MP cows the relationship between insulin-like growth factor-I and yield switched from negative to positive between weeks +4 and +7. Both beta-hydroxybutyrate and urea were positively related to yield in PP cows. In contrast, in MP cows beta-hydroxybutyrate was negatively correlated with yield and urea was strongly related to body condition score but not yield. These results suggest that there are differences in the control of tissue mobilization between PP and MP cows which may promote nutrient partitioning into growth as well as milk during the first lactation.     

Behaviour of domestic ducks exposed to mobile predator stimuli. 1. Flock responses

1. Small flocks of ducks (Anasplatyrhynchos domesticus) were exposed to two stimuli, a small mobile vehicle and a walking human, to investigate their flight responses. 2. Experiment 1. Flocks were herded around an annular arena by each stimulus at 0.5 ms(-1) and the flight distance between the stimulus and the centre of the flock, and individual positions within the flock were recorded every 10 s. Flocks maintained a significantly longer distance from the human (6.0 m) than the vehicle (5.1 m) and usually did not maintain visual contact with either stimulus. Significant consistency in individual positions within the flock was found within and between trials. 3. Experiment 2. Flocks were exposed to each stimulus which approached them as they were feeding in a circular arena. The latencies for cessation and resumption of feeding were recorded and the paths followed by the flocks described. Ducks showed a significantly shorter latency to cease feeding in response to the human (4.9 s) compared with the vehicle (6.9 s). 4. Domestic ducks apparently perceive an approaching human as a greater threat than a small vehicle. The findings are discussed in relation to the development of herding robots.     

Ultraviolet light and mating behaviour in domestic broiler breeders

1. The perception of UVA light (320 < lambda < 400 nm) by domestic fowl may be an adaptation to naturally lit habitats and may still be functional in farmed varieties, although not utilised owing to the absence of these wavelengths in commercial house lighting. One function may be the mediation of sexually related signalling or communication. 2. In experiment 1, two groups of 41 adult broiler breeders (four cockerels, 37 hens) were kept under conventional fluorescent light, with or without fluorescent UVA supplementation amounting to 16.9% of the total spectral power output of the luminaires. Each light environment was approximately iso-illuminant as perceived by the birds. The two groups were exposed to the light environments alternately for five 2-day periods in a cross-over design. Mating behaviour, production measures and time budgets were recorded on the second day of each period. 3. A UVA-enriched environment increased the number of attempted matings (1.27 vs 0.99 matings/cockerel.h) and locomotion (5.3 vs 3.7 min/bird.hour). 4. In a second experiment, 10 hens were allowed to choose between four cockerels lit under different power levels of UVA (1.6%, 14.6%, 43.5%, 57.5% of the total spectral power output of the luminaires) in a four-armed maze. Again, each light environment was approximately iso-illuminant as perceived by the birds. Each hen was allowed to make one choice per day over four days, with the position of the cockerels and the UVA levels interchanged each day. This schedule was repeated with the same hens for two other groups of four cockerels. 5. At a distance of no less than 60 cm from the cockerel, the hens spent most time inspecting whichever cockerel was lit by 1.6% or 14.6% UVA (1.33 vs 1.37 vs 1.22 vs 1.16 log seconds/hen.choice, respectively for increasing UVA level). Similarly, when allowed to approach closer to the cockerels, the hens spent most time in the arm which contained a cockerel lit by 14.6% UVA light, (1.62 vs 1.88 vs 1.69 vs 1.51 log s/hen.choice, respectively for increasing UVA level). 6. UVA is clearly implicated in the transmission of sexual signals or communication which may have implications for the welfare and production of broiler breeders.     

Microbial cross-contamination by airborne dispersion and contagion during defeathering of poultry

1. A readily identifiable strain of Escherichia coli K12 was used as a 'marker' organism to determine the sources, routes and patterns of microbial cross-contamination during mechanical defeathering of broiler chicken carcases. 2. Inoculation of scald water with the marker organism led to a relatively even pattern of carcase contamination during subsequent defeathering. Microbial cross-contamination was greater by this route of inoculation than by either surface inoculation of a 'seeder' carcase or oral inoculation of a live bird one day before slaughter. 3. Dispersal of the marker organism was strongly influenced by the mechanical action of the defeathering machines. Forward transmission of the marker occurred by aerosol or large airborne droplets and particulates such as feathers. Moving carcases through the defeathering machines when these were non-operational clearly reduced backward transmission of the marker. 4. Although microbial dispersal was unaffected by increasing the spacing between individual carcases or installing a water curtain at the entry and exit of the defeathering machines, shielding of carcases with aluminium baffles reduced counts of the marker organism from contaminated carcases by > 90%. 5. The results imply that microbial cross-contamination of broiler chicken carcases during defeathering occurs mainly via the airborne route, which could be contained by physical means.     

Snake bites recorded by veterinary practices in Australia

Objective To determine the extent of the snake bite problem in domestic animals, its regional significance and the effects of antivenom treatment.
Design A questionnaire was designed seeking information on the number and type of domestic animals referred, whether treated or untreated, type of snakes and management of the bite.
Procedure The survey form was sent to 10% of veterinary surgeons, selected at random throughout Australia.
Results The response of 106 veterinary surgeons revealed that snake bite in domestic animals is frequent, with an estimated 6200 cases reported annually. Bites were more prominent in rural (78%) than urban areas (22%) with brown, tiger and black snakes accounting for 76%, 13% and 6% of cases, respectively. Cats and dogs were the most frequently reported victims. Ninety-one percent of cats and 75% of dogs survived following the administration of antivenom whereas 66% of cats and 31% of dogs survived without antivenom. Overall, in 33% of cases antivenom was not used, and venom detection kits were used in only 1% of cases. A number of drugs were used in various combinations with or without antivenom and intravenous fluids in the treatment of animals with snake bite, but their role in reducing the severity of envenomations was not assessed.
Clinical implications Antivenom significantly improves the chances of survival of domestic animals bitten by snakes.     

Impact of foot-and-mouth disease on mastitis and culling on a large-scale dairy farm in Kenya

Foot and mouth disease (FMD) is a highly transmissible viral infection of cloven hooved animals associated with severe economic losses when introduced into FMD-free countries. Information on the impact of the disease in FMDV-endemic countries is poorly characterised yet essential for the prioritisation of scarce resources for disease control programmes. A FMD (virus serotype SAT2) outbreak on a large-scale dairy farm in Nakuru County, Kenya provided an opportunity to evaluate the impact of FMD on clinical mastitis and culling rate. A cohort approach followed animals over a 12-month period after the commencement of the outbreak. For culling, all animals were included; for mastitis, those over 18 months of age. FMD was recorded in 400/644 cattle over a 29-day period. During the follow-up period 76 animals were culled or died whilst in the over 18 month old cohort 63 developed clinical mastitis. Hazard ratios (HR) were generated using Cox regression accounting for non-proportional hazards by inclusion of time-varying effects. Univariable analysis showed FMD cases were culled sooner but there was no effect on clinical mastitis. After adjusting for possible confounders and inclusion of time-varying effects there was weak evidence to support an effect of FMD on culling (HR = 1.7, 95% confidence intervals [CI] 0.88-3.1, P = 0.12). For mastitis, there was stronger evidence of an increased rate in the first month after the onset of the outbreak (HR = 2.9, 95%CI 0.97-8.9, P = 0.057).

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-015-0173-4) contains supplementary material, which is available to authorized users.