Average Bird Weight Research Articles

Use of live oocyst vaccines in the control of avian coccidiosis: experimental studies and field trials

Areas addressed in this study on the use of live oocyst vaccines to control coccidiosis include: the influence of immunocompetency of the strains and sex of the birds used; methods of delivery of vaccine; immunological variation between different strains of the same coccidial species; and the effects of combining vaccine with anticoccidial medication. The results show that vaccination with live oocysts elicited significant protection against coccidiosis, both with exper imentally induced and naturally acquired coccidial infection, resulting in average bird weight gains and feed effciency similar to that obtained with conventional anticoccidial medication.

Incubation and brooding rhythm of the Cape Petrel Daption capense at Nelson Island, South Shetland Islands, Antarctica

Incubation and brooding performance of the Cape Petrel Daption capense at Nelson Island, South Shetland Islands, Antarctica, in the 1991 ‐1992 austral summer is reported in detail and compared with data from two other areas. There was an inverse relationship between the mean foraging trip length and mean peak weight of chicks. Variation in shift length throughout incubation resulted from a combination of seasonal effects (food supply) and behavioural adjustment to hatching. The length of the last incubation shift was independent of its number but decreased with date of initiation. The average weight of nestattending birds increased steadily during the incubation period and at the same rate in both sexes. Females attained seasonal peak body‐weight before the egg hatched, whereas males just recovered their pre‐breeding weight. Males took on a slightly larger share of incubation (52%, range 40–63%) and invested more time in mutual nest attendance. Length of foraging trips varied consistently in pairs and individuals, its repeatability being twice as high in females as in males. The incubation performance of individual females (length of the first and an average foraging trip) was correlated with the size of the egg they had laid and also to subsequent chick growth and fledging success. There was a tendency in successful pairs to spend more time together at the nest and to have shorter foraging trips. I suggest that variation in breeding performance among pairs was mainly a result of individual variation in female quality, with pairs where the female contributed more to incubation being more successful. There is little evidence that egg losses were caused by parental errors.

Effect of intermittent activity on broiler production parameters

The use of intermittent lighting in broiler production has been shown to result in spurts of activity that appear to reduce lameness. Because intermittent lighting is difficult to achieve in curtain-sided houses, the objective of this study was to determine whether simple equipment used to increase activity in broilers would improve production variables. At 1 d of age, 840 male broiler chicks were placed in 24 floor pens. The four treatments (six replicates of 35 chicks each) were as follows: 1) Control-standard feeders, 2) Ramps and Toys-birds had to climb a slight incline ramp to reach feeder and had a hanging mobile, 3) Ramps only, and 4) Toys only-standard feeders. Two trials were conducted. Weekly group weights and feed consumption were recorded. Mortality was recorded daily. At 6 wk of age, birds were bled, euthanatized, weighted, and scored for ascites and tibial dyschondroplasia (TD), and relative heart, liver, and spleen weights were obtained. Blood samples were analyzed for blood gases, hemoglobin, red blood cell count, and clinical chemistries were performed. In Trial 1, during Weeks 2, 3, and 4, treatments with ramps had significantly heavier average bird weight and significantly lower feed:gain ratios. In Trial 2, treatments with ramps had no difference in average BW; however, these groups consumed less feed, resulting in significantly lower feed:gain ratios. Cumulative mortality was decreased by ramp treatment in Trial 2. Toys decreased the incidence and severity of TD in Trial 2. In general, organ weights, blood gases, hematologies, and clinical chemistries were not affected by treatments. However, birds in treatments with ramps had significantly lower serum calcium and smaller hearts in Trial 1, and significantly lower serum cholesterol and smaller hearts in Trial 2.

Description of Cellulitis Lesions and Associations between Cellulitis and Other Categories of Condemnation

A total of 110 broiler flocks processed in a single processing plant in southern Ontario were studied for purposes of describing the cellulitis lesions and investigating possible associations between cellulitis and other categories of condemnation at the processing plant. Two hundred and ninety-five carcasses condemned for cellulitis were examined. They came from 65 of the 110 flocks. The lesions tended to be unilateral with most carcasses (87%) having one lesion. The majority of the lesions (92%) were located on the abdomen. Almost 65% of the lesions were large (> or = 8.1 cm2), and 27% were medium (2.1-8.0 cm2). On the basis of gross appearance, 69% of the lesions were classified as severe, 26% moderate, and 5% mild. Of 149 lesions examined histologically, 74% were classified as chronic, 21% ongoing, and 5% mild-acute. Condemnation data from the 110 broiler flocks were analyzed using Poisson regression. Simple relationships were examined between a count outcome (number of cellulitis-condemned carcasses per flock) and other categories of condemnation and average bird weight. Cellulitis was significantly associated with average bird weight (P = 0.0018), Escherichia coli-related conditions (SEROSITIS; P < or = 0.0001), ascites (P = 0.0004), cyanosis (P < or = 0.0001), valgus varus deformity (P < or = 0.0001), REJECT (combined carcass condemnations for bruising, mutilation, and contamination; P = 0.0003), and the interaction terms "average bird weight and ascites" (AVWT*ASCIT; P < or = 0.0001) and "average bird weight and cyanosis" (AVWT*CYAN; P < or = 0.0001). Average bird weight, SEROSITIS, ascites, cyanosis, valgus varus deformity, and AVWT*ASCIT were the only significant factors after adjusting for clustering. No association was observed between cellulitis and emaciation and dead on arrival. Variables significantly associated with cellulitis in the multivariate analysis could be considered as potential predictors. These predictors may share common risk factors predisposing broiler chickens to cellulitis.

A Prospective Study of Cellulitis in Broiler Chickens in Southern Ontario

This study investigated the associations among cellulitis and hatchery, farm, and abattoir factors. Forty-four broiler flocks from 24 farms located in southern Ontario were followed from hatching to processing. Poisson regression was used to analyze the data. Cellulitis as a count outcome (CELLCOUNT) was significantly associated (P < or = 0.05) with the hatchery of origin, strain of birds, farm size, type of litter, lighting system, total down time, prevalence of abdominal scratches, Escherichia coli-related conditions (SEROSITIS), ascites, and valgus varus deformity. However, only farm size, abdominal scratches, SEROSITIS, ascites, and valgus varus deformity were significant (P < or = 0.05) after adjusting for clustering. No significant associations were found between cellulitis and source of eggs, sex, average bird weight, feed company, growth promoter, or stocking density. Factors significantly associated with cellulitis in this study could be considered as potential risk factors for cellulitis in broiler chickens in southern Ontario.

Phosphorus-31 nuclear magnetic resonance spectroscopy of liver from two broiler chicken lines

Hepatic levels of phosphorus-containing compounds that are related to fat metabolism in the liver of two broiler lines with different body-fat content were assessed using high-resolution 31P NMR spectroscopy. PCA extracts of livers from 16-d-old chicks were analyzed with an NMR spectrometer. The results demonstrated that the concentrations of G3P, AMP and phosphocholine were significantly higher in the livers of LL birds than in those of the FL birds (P &lt; 0.05). Differences in hepatic concentration of GPE and GPC were not detected between the two lines. It was also found that the liver weight per unit body weight of the FL chickens was less than that of the LL birds (P &lt; 0.01). Average body weight of FL birds at 16 d of age was lighter than that of LL birds (P = 0.01). The FL birds deposited more (P &lt; 0.05) fat per unit body weight than the LL birds. However, no statistical difference (P &gt; 0.05) was found in protein deposition per unit body weight between the two lines. These results indicate that liver size and the concentration of hepatic phosphorus containing compounds are related to the partition of energy in broiler chickens. Key words: NMR spectroscopy, phosphorus-containing compounds, fat deposition, liver, broiler chicken

The cost benefit of vaccinating broiler flocks against subclinical infectious bursal disease

In an attempt to reduce economic losses due to subclinical infectious bursal disease (IBD), broilers reared in 23 houses known to have been infected with IBD virus were vaccinated with live, attenuated IBD virus vaccine at 20 days of age. Vaccination of either one, two or three consecutive flocks resulted in significant increases in net income and average bird weight, and in a decrease in mortality. An improvement in broiler performance was not restricted to vaccinated flocks, but was also apparent for at least 1 year following placing of the first vaccinated flock in subsequent flocks reared in the same houses.

Effects of forest regeneration on the structure of bird communities in northern Finland

Breeding bird communities in five stages of secondary forest succession were studied in northeastern Finland in 1980–82. Three groups of communities were distinguished: open land, brush phase and forest communities, dominated by Motacilla alba and Oenanthe oenanthe, Phylloscopus trochilus and Anthus trivialis, Phylloscopus trochilus and Fringilla montifringilla, respectively.Pair density, number of species, biomass of adult birds and species diversity increased in the course of succession, none of these, however, monotonously. Average bird weight showed a decreasing trend although the variation was considerable. The degree of specialization in communities (measured by ratios derived from numbers of species, genera and families) increased in the course of succession with the exception that the initial stage had relatively high values. Species nesting and feeding in trees and shrubs increased in numbers during forest regeneration whereas species nesting and feeding on the ground showed the opposite trend. The proportions of hole‐nesting and sedentary species increased with increasing forest age.The initial stages of forest succession in the north are occupied by specialized open habitat species breeding originally on open bogs and shores. These communities thus clearly differ from those predicted from the general theory of succession, which postulates that the pioneer stages of succession are dominated by habitat generalists and that these communities should have relatively low values of community diversity.

Observations on New and Reused Litter for Growing Broilers

Three of five houses on a commercial broiler farm were cleaned, and hardwood sawdust was spread to a depth of about 3 cm prior to the arrival of chicks. Hard or caked litter was removed from the remaining two houses, and litter was top dressed with about .25 cm of hardwood sawdust. Litter samples were collected weekly from each house. Moisture, pH, and mold counts were determined for each sample. No significant differences were detected in average bird weight, feed conversion, mortality, or condemnations. Litter moisture and pH values increased over the course of the experiment, whereas litter ash values showed no consistent trends. The highest mortality for birds on both litter types occurred in the first week of the experiment. However, the data suggest that when new litter is used for broilers, mortality is more evenly distributed over the grow-out period.

Growth in the hubbard broiler: Increased size following early handling

Hubbard cockerels, 1 day of age (n = 91), were divided into 3 handling groups: (1) chicks from the 5-Day group were removed from the brooder and isolated at 22 degrees C for 3 min on each of the first 5 days; (2) chicks from the 15-Day group received this treatment for 15 days; and (3) Control chicks were not handled. Within each group half were fed broiler starter for 5 weeks, and half were fed layer starter which produces slower growth. On Days 28, 35, 42, and 49 the average weight of 5-Day birds was significantly higher than that of Controls; 15-Day birds weighed slightly less than birds in the 5-Day group. The weight advantage of the 5-Day birds occurred with both starter rations, at all weighing periods, and did not appear to reflect increased food consumption. Similarities between these findings and results obtained with rodents were noted.