Influence of coccidiosis on growth rate and feed conversion in broilers after experimental infections with Eimeria acervulina and Eimeria maxima.

Under experimental conditions, the effects of subclinical Eimeria (E.) acervulina and E. maxima infections on growth and feed conversion in broilers of different ages were analysed. It was concluded that infection with E. acervulina and E. maxima led to a process which was independent of the age at which the birds were infected. The infection adversely affected growth and feed conversion for 2 to 3 weeks, followed by a recovery period of 2 to 3 weeks when compensatory growth took place. From this study it may be concluded that subclinical coccidiosis in the first weeks of life and in the last week of life of broilers does not lead to appreciable damage on growth and feed conversion. Since coccidiosis cannot be avoided in practice, systems in which broilers contact subclinical coccidiosis either in the first weeks of life or in the last week of life should be aimed for. It is suggested that in a coccidiostat programme an efficient anticoccidiosis agent is particularly desirable in the 3rd and 2nd week before slaughter. Examinations performed one week or less before slaughter can hardly be justified, on the grounds that there is a risk of a negative effect on growth an feed conversion due to subclinical coccidiosis.

[Analysis of losses due to subclinical small intestinal coccidiosis caused by Eimeria acervulina and Eimeria maxima under field conditions]. / Een analyse van de schade van subklinische dunne darm coccidiosis veroorzaakt door Eimeria acervulina en Eimeria maxima onder praktijkomstandigheden.

Subclinical coccidiosis of broiler chickens caused by Eimeria (E.) acervulina and E. maxima results in a negative effect on feed conversion and retardation of growth. In the present report investigations in 80 broiler flocks are described in which the relationship between age of infection and economic effects were analysed under field conditions. Under these conditions, infections with E. acervulina and E. maxima were found to have a negative effect on growth and feed conversion, that this negative effect persists and accumulates for approximately three weeks following infection, and is subsequently completely or partly compensated for by increased growth rates. In the present study it was established that the losses due to subclinical coccidiosis of the small intestine in the 80 flocks investigated amounted to 6.4 cents per chicken under conditions occurring in the Netherlands. Ionophorous coccidiostats did not prevent infection with E. acervulina and E. maxima but did prevent infections with E. brunetti, E. necatrix and E. tenella.

Comparison of the effect of live Newcastle disease vaccine Clone 30 in broilers administered at day 1 or at day 7 and the effect of H120 vaccination at 17 days of age: a field experiment.

To analyse the results of a vaccination on the first day of age against Newcastle disease (ND) and on the 17th day of age against Infectious Bronchitis (IB) resp. with spray vaccines with Clone 30 and H120 vaccine. These vaccinations are compared in field circumstances with other vaccination methods. A serological examination and challenge test were used to be informed about the response and protection. From the present study the following conclusions can be drawn: Clear indications are obtained that following a spray vaccination against ND with Clone 30 vaccine of one-day-old broilers which possessed maternal antibodies, birds received a moderately good protection against ND, in spite of very low levels of HI antibodies. A spray vaccination against IB with H120 vaccine of broilers at 17 days of age gave some protection from two weeks after vaccination, however making a good conclusion about the protection is impossible and further investigation is required.

The use in practice of inactivated oil emulsion vaccine against infectious bursal disease in broiler breeders and its influence on the progeny: a comparative field trial.

Field trials were conducted to establish the effect of the use of an inactivated oil emulsion vaccine against Infectious Bursal Disease (IBD OEV) in broiler breeder hens, and its effects on their progeny. The performance of 18 broiler flocks, which were the progeny of the IBD OEV vaccinated breeder hens, but which were not vaccinated with a live vaccine against IBD, was equal to that of broiler flocks which were vaccinated with a live IBD vaccine and originated from parent stock that had been vaccinated only against IBD with a live vaccine. In none of the 18 flocks, progeny of IBD OEV vaccinated parents, was IBD diagnosed. In a second stage, 15 broiler flocks were included in the trial: these were derived partly from IBD OEV vaccinated parents, and partly from parents that received only live IBD vaccine at 8-10 days of age. No cases of IBD occurred and all flocks were positive for IBD precipitins at slaughter age. Vaccination with a live vaccine against IBD at the age of 8-10 days had no influence on NCD antibody development after a NCD vaccination at 7 days. No immunosuppressive effect from this type of live live IBD vaccine could be determined under field conditions.

A study of the effects of replacing monensin ionophore with lasalocid ionophore in the field control of coccidiosis in broilers.

The following conclusions are made from an introductory investigation on the use of the coccidiostat lasalocid on 11 production farms of an integrated broiler production organisation. In terms of the incidence of sub-clinical coccidiosis, no significant difference was found between the previous use of monensin and the use of lasalocid during the investigation. However, the incidence of coccidiosis decreased with the introduction of lasalocid. Despite the fact that on some farms sub-clinical coccidiosis was diagnosed, the production performance clearly improved with lasalocid. EBI figures significantly increased from 163.6 to 172.5. During the investigation, in which approximately 220,000 broilers were involved, litter quality did not differ from that of previous crops in which monensin had been used. Feathering of the broilers in the trial crops in which lasalocid was used was similar to that of previous crops.

The hygienic treatment of turkey eggs by dipping in an antibiotic and disinfectant solution.

At the hatchery, in order to reduce bacterial infections in one-day-old chicks, turkey eggs are routinely dipped by the direct pressure difference method into a solution consisting of: (formula; see text) This dipping process was studied in more detail and the experiments allowed of drawing the following conclusions: 1. After 8 hours of use on three consecutive days the tylosin concentration had hardly decreased, the concentration of ampicillin dropped to approximately 65% and the concentration of quaternary ammonium compounds to 33%. 2. Bacteria were isolated from the fluid only at the time of final sampling (Bacillus subtilis). All other bacteriological investigations of the dipping solution showed negative results. 3. The treatment did not appear to influence hatchability. 4. The mortality in the first week of life of poults from treated eggs was significantly lower than of poults from untreated eggs.

[Rickets-like changes in broiler chickens (author's transl)]. / Rachitisachtige afwijkingen bij slachtkuikens.

A disease in broiler chickens associated with rickets-like symptoms observed on post-mortem examination is described. The disease is not caused by deficiencies in the feed. Treatment with vitamin D3, calcium and phosphorus has little if any effect. There is evidence to suggest a relationship with the origin of the broilers. It also is an established fact that the disease is related to the farm. Particularly those broilers will develop rickets-like symptoms, which were housed on litter previously used for chickens with the same disease. It probably is an infectious disease. Non-purulent inflammation of the glandular stomach is constantly observed in chickens showing rickets-like symptoms. This disease is transmissible to SPF chickens. It is not clear whether this is an accidental finding or typical of this clinical picture.

[Effectiveness of a number of anticoccidial agents. A brief survey taken in the field (author's transl)]. / De werkzaamheid van een aantal anticoccidiosismiddelen. Een momentopname in de praktijk.

A floor pen trial was carried out on broilers in 1975 to compare the anticoccidial efficacy of monensin1), 3,5 dinitro-o-toluamide2), clopidol3), amprolium + ethopabacte4), amprolium + ethopabate + sulfaquinoxaline + pyrimethamine5) and robenidine6) in the presence of untreated controls. 4,200 Hybro chicks were distributed over twenty-eight pens, each initially housing 150 birds. Four pen replicates were allocated to each of the seven treatments. With the exception of robenidine, all agents used resulted in a statistically significant (P less than or equal to 0,05) gain in final weight compared with the untreated controls. The feed conversion rate showed significant (P less than or equal to 0,05) improvement in the groups treated with monensin, robenidine, amprolium + ethopabate.

Comparison of live Newcastle disease vaccines in a simple vaccination and challenge experiment.

Groups of day-old chicks with haemagglutination inhibiting antibodies (HIA) were exposed by the spray method to equal doses of three different live Newcastle disease (ND) commercial vaccines and allantoic preparations of them. After three weeks the HIA response was measured and the chicks were challenged with a pathogenic strain of Newcastle disease virus (NDV). The degree of protection of each bird was compared with its HIA response. The commercial vaccines all provided good protection at identical levels, but significant differences were detected between the allantoic fluid preparations. Two of the commercial vaccines produced significantly better protection than the allantoic fluid preparations. In addition to the protection conferred by HIA antibody, other mechanisms of protection apparently played a part.

[Drug residues in poultry (author's transl)]. / Residuen van geneesmiddelen bij pluimvee

The following microbiological tests: the Bacillus subtilis BGA (Bundes-Gesundheitsamt) test and Sarcina lutea test as well as the test bacteria Bacillus stearothermophilus var. calidolactis and E. coli were used to examine whether drug residues were detectable in broiler chickens during and after treatment with various drugs. With the exception of the occidiostat Esb3, residues were not found to be present using the two above tests. On the other hand, residues of a number of drugs were detected in some interior organs and faeces during treatment when the other test bacteria were used. Residues were no longer detected in the faeces, however, within twelve hours after treatment had been discontinued.

[Poultry vaccination against N.C.D. by means of an intramuscular injection with LaSota strain vaccine; a practical investigation (author's transl)]. / Het vaccineran van pluimvee tegen NDC. door middel van intramusculaire injectie van LaSota entstof; een praktijkonderzoek

An intramuscular N.D.C. vaccination with LaSota vaccine, in animals of less than ten weeks which were previously vaccinated by the spray method at about 5 days and 25 days against N.C.D., leads to an immunity of at least three months, as expressed by a high concentration of haemagglutination inhibiting antibodies in the circulatory system. If the vaccinated animals are older than twenty weeks, the resulting immunity is very high indeed and shows practically no impairment within a year after vaccination (longer periods have not been investigated), so that it may be assumed that revaccination will not be necessary during the laying period. Antibody variations between different animals of a flock are slight. The residual immunity of previous vaccinations did not appear to affect the development or maintenance of the antibodies. No spread of vaccine was observed. Here it should be noted that animals with a low residual immunity were used for control. It would be desirable to use specifically pathogenfree animals for this purpose, but this is not really practicable in field conditions. Half a hen dose of the LaSota vaccine, dissolved in 1/2 ml physiological saline, was injected into the pectoralis muscle with the help of the Cornwall Pipetting Unit. Twenty flocks, involving 6900 animals, were vaccinated in field conditions. Not a single vaccination gave rise to any vaccination reaction. The method does have a high labour content; which is an objection.