Rupture of gastrocnemius tendon in broiler breeder hens

Lameness and mortality of 0.55% to 1.00% per week occurred in 32-to-33-wk-old broiler breeder hens in a complex involving eight houses. Males were not affected. Laboratory evaluation of 19 birds, over 2 wk, revealed complete rupture or partial tear, primarily of the gastrocnemius tendon; the fibularis longus, fibularis brevis, and flexor muscles and their tendons were injured in a few birds. Rupture of the gastrocnemius tendon has been observed in broiler breeder chickens older than 12 wk of age and it is characterized by lameness secondary to unilateral or bilateral rupture of the tendon. The cause of this condition has been primarily attributed to reovirus infection but rupture by other causes can also occur. In this case, there was no evidence of synovitis or reovirus infection in the birds. The cause of the ruptures was attributed to aggressive males when the ratio of males to females was increased from seven or eight males per 100 females at 22-23 wk to nine or 10 per 100 at 31 wk of age.     

Chicken anemia agent in the United States: isolation of the virus and detection of antibody in broiler breeder flocks

Chicken anemia agent (CAA) was isolated from broiler chickens in Texas with a blue wing or anemia dermatitis-like syndrome. Specific-pathogen-free chicks inoculated with field material developed anemia, and CAA was isolated in MDCC-MSB1 cells from bone marrow and lymphoid tissue from inoculated chicks. One isolate, designated EF88/78/276, was further characterized. Infectivity of EF88/78/276 was resistant to treatment with chloroform and with heat at 70 C for 5 minutes. EF88/78/276 was indistinguishable from the Cux-1 and Gifu-1 isolates of CAA by cross-neutralization tests. Almost all 1-day-old susceptible chicks inoculated intramuscularly with EF88/78/276 developed anemia, but contact-infected chicks did not. Antibody to CAA was detected in broiler breeder flocks from Texas, the Delmarva peninsula, and Alabama.     

Evaluating hydrolyzed yeast in the diet of broiler breeder hens

One of the greatest challenges for nutritionists is ensuring that breeder hens consume the quantity of nutrients necessary to ensure proper development while also ensuring the production of good quality chicks. However, new studies must investigate how nutrition can positively affect the performance of these poultry. The present study aimed to evaluate hydrolyzed yeast supplementation in the diet of Cobb 500 broiler breeder hens, starting from 25 wk of age, and to evaluate the performance of the hens and their progeny. Broiler breeder hens fed hydrolyzed yeast supplement exhibited better performance compared with the control group. The results of the progeny demonstrated improved performance in chicks from the breeder hens fed the hydrolyzed yeast supplement. However, no improvement was observed in breast or leg yields; only carcass yield improved in these broilers. The results demonstrate that supplementation with hydrolyzed yeast in the diet of broiler breeder hens improves the performance of hens and their progeny.     

Avian leukosis virus subgroup J infection profiles in broiler breeder chickens: association with virus transmission to progeny

Profiles of infection with avian leukosis virus subgroup J (ALV-J) and factors that predict virus transmission to progeny were studied. Eggs from an infected broiler breeder flock were hatched at the laboratory. The flock was reared in a floor pen, transferred to laying cages at 22 wk, and inseminated to produce fertile eggs. A cohort of 139 chickens was tested at frequent intervals over a 62-wk period for virus, viral antigens, or antibodies in plasma, cloacal swabs, egg albumen, and embryos. Virus was detected in 7% of chicks at hatch but spread rapidly so that virtually all chicks became infected between 2 and 8 wk of age. Mortality due to myeloid leukosis and related tumors was 22%. Over 40% of the chicks developed persistent infections, whereas the remainder experienced transient infections. Five types of infection profiles were recognized. Novel responses included hens that were positive for virus intermittently or started late in life to shed viral antigens into the cloaca. ALV-J was isolated from 6% of 1036 embryos evaluated between 26 and 62 wk. However, over 90% of the virus-positive embryos were produced between 29 and 34 wk of age. Of 80 hens that produced embryos, 21 produced at least one infected embryo and were identified as transmitters. All but one transmitter hen would have been detected by a combination of viremia, cloacal swab, and albumen tests conducted between 18 and 26 wk. However, virus was transmitted to embryos from hens that were not persistently viremic or that rarely shed viral group-specific antigen into the albumen of their eggs. Intermittent patterns of both antigen shedding and virus transmission to embryos were observed in some hens. These results validate current screening procedures to identify potential transmitter hens and provide some suggestions for improvement but also show that identification of all transmitter hens by such procedures is unlikely. Thus, eradication programs based solely on dam testing may be less effective than those where dam testing is combined with procedures to mitigate early horizontal transmission in progeny chicks.     

Myopathy of the deep pectoral muscle in broiler breeder hens.

Myopathy of the pectoralis profundus and ambiens muscles was found in chickens from 5 flocks of broiler breeder hens. Histological lesions in the muscles varied from steatosis to loss of striations, fragmentation of fibers, and mineral deposition. A clinical response followed oral medication with vitamin E and selenium although analysis showed that selenium and vitamin E levels in the feed were normal. The possible relation between myopathy and Cassia seed in the feed is discussed.     

Effect of a live reovirus vaccine on reproductive performance of broiler breeder hens and development of viral tenosynovitis in progeny.

A live commercial reovirus vaccine, Enterovax, was administered to adult broiler breeder hens via the drinking water to determine its efficacy in stimulation of circulating antibody. This vaccine was compared with a commercial inactivated reovirus vaccine. Only the inactivated product resulted in increased antibody as measured by a commercial enzyme-linked immunosorbent assay. However, the live reovirus vaccine caused diarrhea in the hens and decreased eggshell quality, fertility, and hatchability. In addition, the live vaccine virus was vertically transmitted from hens to their progeny, resulting in increased embryonic mortality and viral tenosynovitis.     

Prevention of foot lesions in broiler breeder hens kept in individual cages

Individually-caged broiler breeder hens were fed allowances of 1.88, 1.61, 1.32 or 1.13 MJ apparent metabolisable energy (AME) per 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. A system of foot scoring was used to assess the extent and severity of foot damage. Damage increased as energy intake increased but protein intake had little effect on foot condition. Cushion floors or perches introduced into the cages at 27 weeks of age reduced the deterioration in foot condition observed on all dietary treatments during lay. Egg output was not affected by foot condition although severe foot damage was observed in several cases.     

Effect of density and season on stress and behaviour in broiler breeder hens

1. We examined the effect of density (5, 7, 9 and 11 birds/m2) and season (summerand winter; different hens each season) on stress and behaviour in two flocks of 64 broiler breeder females divided among 8 pens. 2. The hens, approximately the same age and body mass in each season, were maintained on hard-packed ground, without litter, in an open-sided chicken house and were offered the same amount of food each season. 3. Mean house max/min temperatures varied between 18 and 33 degrees C in summer and 7 and 17 degrees C in winter. Mean relative humidity in summer varied between 68% at 08:00 h and 42% at 14:00 h and in winter was 64% at 08:00 h and 47% at 14:00 h. 4. No difference was found in heterophil:lymphocyte ratios among densities and between seasons; however, basophil numbers were higher in winter than in summer indicating prolonged stress in winter. 5. Stereotyped pecking increased with an increase in density and was higher in winter than in summer. Pecking on the ground was higher in winter, but was not affected by density. 6. In summer the hens spent more time lying and eating than in winter, whereas in winter the hens spent more time walking, preening and drinking than in summer. They spent the same amount of time standing in both seasons. None of these behaviours was density dependent. 7. We conclude that season had more of an effect than density on stress and behaviour in broiler breeder hens under the conditions of our study.     

Serum neutralizing antibody titers in dairy cattle administered an inactivated vesicular stomatitis virus vaccine

Two doses of a formalin-killed, cell culture-derived vesicular stomatitis virus (vsv)-New Jersey serotype vaccine were administered intramuscularly, 30 days apart, to all lactating and nonlactating cows in a 350-cow dairy herd. Serum specimens were obtained serially from 96 cows before vaccination and at 30, 52 and 80 days after vaccination and from 24 of these cows 175 days after vaccination. Serum neutralizing antibody titers to vsv-New Jersey serotype were determined from serum-dilution, plaque-reduction tests. Serum neutralizing antibody titers also were determined during the same period for 67 nonvaccinated heifers in the herd. Peak group geometric mean serum neutralizing antibody titers of 1:530.46 +/- 1.14 (group geometric mean titer log10, 2.725 +/- 0.055) developed 21 days after the second vaccination, but decreased to a low value of 1:65.36 +/- 1.38 (group geometric mean titer log10, 1.815 +/- 0.142) by 175 days after vaccination. The nonvaccinated group had no detectable antibody titer to vsv-New Jersey serotype throughout the study. All serum specimens from the vaccinates and controls were negative for heterologous reactivity to vsv-Indiana serotype.     

The experimental production of big liver and spleen disease in broiler breeder hens

SUMMARY Big liver and spleen disease (BLS) was reproduced experimentally by intravenous (IV) and oral (PO) administration of BLS inocula to susceptible broiler breeder hens 34 to 36 weeks of age. Serological and pathological signs of BLS similar to those seen in the natural disease occurred in inoculated and in-contact birds. Splenomegaly was the earliest and often the only necropsy finding, with hepatomegaly and kidney enlargement occurring in some birds later in the course of the disease. After IV administration, serum antigen was detected between 2 and 4 weeks, and antibody between 3 and 5 weeks. After PO administration, antigen was detected between 2 and 4 weeks, and antibody between 3 and 6 weeks. Antibody persisted in all birds to the end of the experiment (6 weeks), and horizontal transmission probably occurred since in-contact birds developed BLS. Liver probably contained the highest concentration of BLS agent because it had the highest infectivity.     

Relationship between fertility duration and in vivo sperm storage in broiler breeder hens

1. Seventy Hubbard hens, 75 weeks of age, were divided into groups containing equal numbers of hens on the basis of duration of fertility. Average fertile periods were 14.5 d (long, L) and 6.9 d (short, S). Each hen was artificially inseminated (AI) on three consecutive days with an average of 1.61 X 10(9)/0.05 ml spermatozoa per insemination. Seven hens from each group were killed 1, 3, 6, 9, and 13 d after insemination. 2. Three longitudinal sections of uterovaginal junction were evaluated microscopically for spermatozoal storage capacity by assigning each sperm host gland (SHG) to one of 5 categories: unscorable, empty, one to 5 spermatozoa, 6 to 20 spermatozoa and greater than 20 spermatozoa. 3. The only significant difference in sperm storage at any time between the L and S duration groups occurred at day 1 after AI, when L duration hens possessed significantly more glands with more than 20 spermatozoa. 4. One day after AI the proportion of SHG containing sperm were 28.8% (L group) and 18.6% (S group). There was a significant decrease in the number of glands containing 1 to 5, 6 to 20 and greater than 20 spermatozoa between days 1 to 3 in both groups. 5. Numbers of glands in all categories containing sperm decreased throughout the 13-d period. The L duration group possessed 18.5% more glands with 1 to 5, 6 to 20 and greater than 20 spermatozoa than the S duration group. 6. There were no significant differences between groups in the proportion of unscorable or empty glands throughout, which ranged from 35.9 to 56.8% and 36.3 to 47.1%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

The response of broiler breeder hens to dietary lysine and methionine.

1. Broiler breeder hens were used in an experiment lasting 10 weeks (29 to 38 weeks of age) to measure the responses to dietary lysine and methionine, the main objective being to determine whether the coefficients of response to these amino acids were the same for broiler breeders and for laying pullets. 2. The hens were offered 150 g/d of one of 20 dietary treatments, 10 being lysine-limiting and 10 being methionine-limiting. The diets were mixed by diluting one of two concentrate (summit) mixes with a protein-free dilution mixture. The lysine-limiting summit diet was designed to supply approximately 1300 mg lysine/bird d, while the other supplied 520 mg methionine/bird d, when fed at 150 g/bird d. 3. Birds on the 5 lowest concentrations of both lysine and methionine did not consume the allotted amount of food, the amount decreasing, in a curvilinear fashion, to approximately 105 g/bird d. 4. The minimum egg weight recorded was 0.8 of the maximum, whereas the rate of lay of birds fed on the diets with the lowest amino acid concentrations was 0.2 of the maximum. 5. Using the Reading Model, the coefficients of response were calculated to be (for lysine) 16.88 E and 11.2 W, and for methionine, 7.03 E and 1.52 W, where E = egg output, g/bird d, and W = body mass, kg/bird. An average, individual, broiler breeder of 3 kg, producing 45 g of egg output per day, would need 793 mg of lysine and 321 mg of methionine daily. This intake of methionine is similar to that estimated by means of coefficients used for laying pullets, but the lysine requirement would be underestimated by 0.18 if the coefficients for laying pullets were used. 6. The coefficients for maintenance for both lysine and methionine, determined in this experiment, are considerably lower than values published previously, whilst the coefficients for egg output are, in both cases, higher. The resultant flock response curves therefore differed significantly from those in which the coefficients of response for for laying pullets were used.(ABSTRACT TRUNCATED AT 400 WORDS)     

Epidemiology of reticuloendotheliosis virus in broiler breeder flocks

Six broiler breeder flocks from two companies in Mississippi were tested at intervals for reticuloendotheliosis (RE) virus infection. Virus was isolated and antibody demonstrated in all six flocks. Infection was first detected at ages ranging from 13 to 47 weeks. Studies showed that neither congenital transmission from grandparent flocks nor treatment with contaminated vaccines was a likely source of infection; thus, exposure to RE virus was assumed to come from the environment. Virus was isolated from litter samples from two of the flocks, but no specific environmental infection source was identified. Infection rates of flocks differed between the two companies. Although adequate controls were lacking, no performance problems due to RE virus infection were apparent in breeder or broiler progeny flocks. However, the RE viruses isolated from these flocks were immunosuppressive and oncogenic when inoculated into day-old chicks. A moderate (3-16%) incidence of neoplasms was induced by contact exposure to these field isolates in the laboratory.     

Recovery of Campylobacter from segments of the reproductive tract of broiler breeder hens

Three groups of >60-wk-old broiler breeder hens were assessed for the presence of Campylobacter within segments of the reproductive tract. In the first group, after stunned, the hens were bled, scalded, and defeathered, the reproductive tracts were aseptically excised from 18 hens, six from each of three adjacent floor pens that were feces positivefor Campylobacter. The reproductive tract segments (infundibulum, magnum-isthmus, shell gland, vagina, and cloaca) were pooled by pen. In the second group, 10 individual hens were sampled from the pens; the reproductive tract was divided into the following segments: magnum, isthmus, shell gland, vagina, and cloaca. For the third group, hens were obtained from two commercial farms that had been determined to be feces positive for Campylobacter, and the reproductive tract was divided into five segments, as described for the second group. Segments of the reproductive tract were placed into sterile plastic bags and suspended 1:3 (w/v) in Bolton enrichment broth, and serial dilutions were plated (0.1 ml) onto Campy-Cefex agar. The agar places were incubated at 42 C for 24 hr in a microaerobic atmosphere. In group 1, the pooled reproductive tract segments for hens from pen A were Campylobacter positive for the shell gland, vagina, and cloaca; hens from pen B were positive for the cloaca only; and hens from pen C were positive for the magnum-isthmus and doaca. In the second group, 9 of 10 cloaca samples were Campylobacter positive. Commercial hens in group 3 had campylobacter-positive cloaca samples (12/12), vagina (10/12), shell gland (7/12), isthmus (2/12), and magnum (4/12). Campylobacter colonization of the reproductive tract of the hen could enable vertical transmission of Campylobacter from the hen to the chick.     

Genetic characterization of chicken anemia virus from commercial broiler chickens in Alabama.

Chicken anemia virus (CAV) isolates show extremely limited genetic variability worldwide. We determined the nucleotide sequence of an 823-nucleotide portion of the 2.3-kb CAV genome found in 10 liver and/or spleen specimens of Alabama 29-to-49-day-old commercial broiler chickens exhibiting lymphocyte depletion of the thymus submitted to the state diagnostic laboratory because of problems unrelated to anemia. We determined the nucleotide sequence directly from DNA isolated from tissues, without isolation of virus in culture. This procedure enabled us to characterize CAV that might not have replicated in culture and avoided the potential for changes during passage. Results confirmed the limited genetic variability of CAV. All sequences were identical in 93% of nucleotide positions. The sequences encoded only two distinct VP1 hypervariable regions, and both had been found previously in other CAV isolates. A novel amino acid, glutamine, was found at VP1 position 22 in half the sequences, replacing the histidine residue encoded by most previously characterized CAV genomes. We were able to distinguish among CAV genomes with different codons at VP1 amino acid 22 and different hypervariable regions by restriction endonuclease analysis of polymerase chain reaction products.     

The role of retinal and extra-retinal photostimulation in reproductive activity in broiler breeder hens

Photostimulation of retinal photoreceptors, which are sensitive to green light, appears to inhibit reproductive activity in birds, whereas photostimulation of extra-retinal photoreceptors, which are sensitive to red light, accelerates it. The objective of this study was to determine the effect of either retinal or extra-retinal photostimulation on reproductive activities of broiler breeder hens. At 23 wk of age, Cobb hens (N = 135) were divided into 9 rooms with individual cages (n = 15). At 24 wk of age, 3 rooms were photostimulated (14L:10D) with white light (Control, n = 45). Six rooms had 2 parallel lighting systems, red (660 nm) and green (560 nm), which were both on during 6 out of 14 h of the light period. Then, in 3 of these rooms, the green light was turned off and hens were exposed to a total of 14 h of red light (Red, n = 45), and in the other 3, the red light was turned off and green lighting continued for a total of 14 h (Green, n = 45). The Green group had reduced egg production; reduced plasma concentrations of ovarian steroids; reduced luteinizing hormone (LH)-β, vasoactive intestinal peptide (VIP), and prolactin mRNA expression; and greater retinal green opsin mRNA expression (P ≤ 0.05). The Red group had greater egg production; greater gonadotropin-releasing hormone-I (GnRH-I) and red opsin gene expression in the hypothalamus; and lesser green opsin gene expression in the retina (P ≤ 0.05). We suggest that selective photostimulation of extra-retinal photostimulation as opposed to retinal photostimulation is a key factor in the determination of successful reproduction of broiler breeder hens.     

Epidemiological and clinical investigations into big liver and spleen disease of broiler breeder hens

SUMMARY The epidemiological and clinical features of big liver and spleen disease (BLS) in flocks on two broiler breeder farms were investigated by serology and gross pathology. The most common necropsy findings on farm 1 were splenomegaly and hepatomegaly, with kidney enlargement in some birds. In one flock (farm 1), a decline in egg production began at 40 weeks of age and lasted for 9 weeks. Seroconversion to BLS antigen was first detected at 45 weeks (3.1% of birds) and increased to 72% at 50 weeks, which coincided with clinical recovery in the flock. Antigen was detected before antibody at 44 weeks and persisted at low incidence (<15%). Farm egg production statistics and serology indicated that the disease affected all flocks on the farm. In three of eight flocks, seroconversion was detected in birds before peak production. The birds in the remaining sheds did not seroconvert or become sick until after peak production. On the second farm, sampling began within a flock already experiencing BLS. Clinical signs and pathology were similar to those seen in flocks on farm 1. However, the lesions that were seen in the pancreas in 15% of birds have not been reported previously. BLS antibody was detected in 78%, and circulating antigen in 14%, of sick birds.