Heat Stress and feeding strategies in meat-type chickens

Heat stress can induce hyperthermia in poultry. A reduction in heat load can be achieved by increasing the possibilities for dissipation, decreasing the level of heat production or by changing the thermal production pattern within a day. Strategies to reduce the negative effects of heat stress can be based on a specific feeding strategy, such as restricted feeding. Feed that is offered long enough before a hot period can ameliorate the harmful effects of high temperature. Another strategy may be to use choice feeding from different feed ingredients, rich in protein or in energy. With such self-selection, the chicken may adjust its intake of individual components, allowing the bird to optimise the heat load associated with the metabolism of the ingested nutrients. Additional promising strategies involve offering a choice between feeds with a different feed particle size or structure. A large particle size contributes to the development of the gastro-intestinal tract (GIT), especially the gizzard and the caeca. A large gizzard will maximize the grinding process and potentially ease digestion down the GIT, thereby reducing heat production associated with digestive processing. Also wet feeding may be profitable under heat stress conditions as well. Feeding wet diets may facilitate an increased water intake and larger particle sizes can limit water excretion in droppings, resulting in more water being available for evaporation during panting, hence cooling the bird. In conclusion, these feeding strategies may help to reduce heat production peaks, facilitate evaporative activity and/or decreases the heat load, resulting in beneficial effects on performance and health of the bird kept in more tropical areas worldwide

Effect of season and farming system on the quantity and nutritional quality of scavengeable feed resources and performance of village poultry in central Tanzania

2 x 2 factorial study was conducted to assess the effect of season and farming system on the quantity and nutritional quality of scavengeable feed resources and the performance of village poultry in central Tanzania. A total of 648 scavenging chickens purchased from farmers were slaughtered and the crop contents were subjected to physical and chemical analysis. The mean fresh weights of the crop contents were higher (

Multiphasic growth in the layer pullet : effects of nutrient restrictions during rearing

Traditionally, layer pullets are reared on a least-cost basis. Feeding regimens, that allow pullets to consume a restricted amount of nutrients, have been designed to control body growth towards a 'target' weight and age. It was questioned whether the pattern of body growth in relation to the rate of development of particular organs during rearing interferes with the productive potential of the young hen. For the present study, it was hypothesized that the supply of nutrients for some organs may be critical at certain ages, as a result of their individual growth patterns. In this thesis, growth and development of the pullet body and its constituents has been studied by means of multiphasic growth functions. It was found that body weight at end of rearing ('target weight') is less important than type (which nutrient?) and phase (what age?) of restriction in determining egg performance. Furthermore, a pronounced growth spurt in the body growth curve was distinguished at around 19 wk of age ('the maturity growth spurt'), that appeared to be related to both the development of the reproductive organs and the onset of lay. The assessment of this growth spurt in a flock may help the producer in taking nutritional decisions. A certain amount of fat-free tissue in the body is suggested to be critical for the initiation of sexual growth. Fat growth at early rearing seemed to be functionally related to growth of the fat-free body: pullets on a low-lysine diet did not increase their fat-to-protein ratio at that stage of development. Fat growth at late rearing is stored as an energy buffer (abdominal fat pad). The composition of the fat-free body was not affected by dietary treatment. It was concluded that the fatfree body of pullets is a better measure of physiological age than body weight. Effects of nutrient restrictions on growth of body constituents should be presented relative to the fat-free body. Multiphasic analyses of pullet growth quantified some growth relationships between body components which had not been revealed if a simple monophasic growth approach had been used

De respons van kalkoenhanen op lysine bij een lage en hoge staltemperatuur

Het doel van het onderzoek dat in dit artikel wordt beschreven, is de respons vast te stellen van jonge kalkoenen op verschillende lysineniveaus bij lage en hoge staltemperaturen

Campylobacter and Salmonella infections on organic broiler farms

Organic poultry production in the Netherlands is developing. Although consumers assume organic products to be safer and healthier, there are aspects of organic animal husbandry, like access to an outdoor run, that can result in increased risks of food safety problems. The aim of this study was to compare housing and management of organic and conventional broiler farms in the Netherlands and to study the occurrence of Salmonella and Campylobacter infections on the former. Large differences were found between the two farming systems with respect to mixed or single farming, manure storage, drinking-water system, ventilation, access to an outdoor run, and pest control. From the 31 organic flocks sampled for Salmonella and Campylobacter in 2003, 13% were positive for Salmonella and 35% for Campylobacter. Results for the summer period are missing due to an outbreak of avian influenza, so the actual number of flocks infected with Campylobacter can be expected to be even higher. Campylobacter appears to be the main risk on organic broiler farms, so that it would be interesting to study specific risk factors of infection with this pathogen on these farms

Effect van verschillende groeicurves en eiwitniveau van het voer op lichaamssamenstelling, productie, kuikenkwaliteit, gedrag en bevedering bij vleeskuikenouderdieren = Effect of different growth patterns and Protein level of the diet on body composition, performance, chick quality, behaviour and feather cover of broiler breeders

In this study the effect of two growth patterns and three different dietary protein levels during the rearing period of broiler breeders was investigated. Applying a low protein diet results in a changed body composition (less breast meat and more abdominal fat) and positive effects on behaviour during rear. Applying a high growth pattern had only slight effects on performance and behaviour. Hardly any carryover effects of the treatments during the rearing period were observed during the laying period

Effect of nutrient dilution and Nonstarch Polysaccharide concentration in rearing and laying diets on eating behavior and feather damage of rearing and laying hens

Verstrekking van verdunde opfokvoeders verhoogde de voeropname van de kuikens vanaf de eerste levensweek. Het lijkt erop dat de kuikens het pikgedrag meer op het voer richten als het verdunningsniveau van het opfokvoer toeneemt. Dit kan leiden tot minder verenpikgedrag. In elk geval was bij leghennen op een leeftijd van 49 weken duidelijk minder schade aan het verenkleed als ze tijdens de opfokperiode 15% verdund voer krege