Effect of diet and natural variations in climates on the performance of laying hens

1. Laying hens raised in 3 natural tropical environments were fed on 2 series of diets with a view to defining the optimum combination of climate and dietary energy.

2. A combination of 3 growing climates, 3 laying climates (temperate, hot dry, hot humid), and 2 dietary energy concentrations (10.03 and 11.70 MJ ME/kg with protein concentrations proportional to energy) were tested for 46 weeks using 432 point‐of‐lay pullets.

3. Both growing and laying climates significantly affected most traits measured during the laying period. The patterns of egg production showed good persistency in all environments and differences observed reduced with age.

4. The difference between the high and low energy intake reduced at high ambient temperatures. Feeding low energy diets did not affect mean age at first egg, rate of lay or the egg output in the hot dry environment, nor egg weight in either hot dry or hot humid climates. Rather, feeding low energy diets resulted in improved body weight change in all 3 laying environments.

5. The growing climate and diet interacted significandy on body weight change, while highly significant interactions between laying climate and diet occurred on rate of lay, food and energy intake and egg weight during the laying period.     

Climatic adaptation of laying hens

Summary Three hundred Warren Isabrown female day old chicks were raised for 18 weeks in 3 distinct artificial climates described as temperate (20°C, 60% RH), hot dry (32°C, 40% RH) and hot humid (32°C, 90% RH). At 18 weeks each group was divided into 3 and re-allocated to 3 similar air-conditioned laying rooms as during the growing period. Different diets were fed to the 3 groups up to 18 weeks. The energy needed in order to produce the same average live body weight at 18 weeks was similar in all the 3 climatic chambers. The effect of treatments in the growing period was not significantly different (P>0·05) for most of the parameters subsequently measured during the laying period. The exception was the body weight gain between 18 and 38 weeks and the food and energy intakes. However, apart from the sexual maturity, all these parameters were negatively influenced (P<0·05) by the effect of hot climates during the laying period irrespective of method of rearing. The results of this study seem to indicate that ambient temperature experienced during the first 18 weeks after hatching has little effect on subsequent productivity and that rearing birds at high ambient temperature does not acclimatise them to these conditions better than rearing them under temperate conditions.

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Adaptacion Climatica De Gallinas Ponedoras

Resumen Se leavantaron 300 pollitas de un día de nacidas, Warren Isabrown, por 18 semanas en 3 climas diferentes; templado (20°C, 60% HR), seco caliente (32°C, 40% HR) y caliente húmedo (32°C, 90% HR). A las 18 semanas cada grupo fue dividido en 3 y re-instalado en 3 cuartos de postura con aire acondicionado durante el período de crecimiento. Los 3 grupos recibieron diferentes dietas hasta las 18 semanas. La energía necesaria para producir el mismo peso promedio a las 18 semanas fue el mismo en las tres cámaras climáticas. El efecto del tratamiento durante el período de crecimiento no fue significativamente diferente (P>0·05) para la mayoría de parámetros medidos subsecuentemente durante el peródo de postura. La excepción fue el aumento en peso corporal entre las 18 y 38 semanas y la energía consumida. Sin embargo, aparte de la madurez sexual, todos los parámetros fueron afectados negativamente (P<0·05) por el efecto de los climas cálidos durante el período de postura, irrespectivamente del manejo. Los resultados de este estudio parecen indicar, que la temperatura ambiente experimentada durante las primeras 18 semanas después del nacimiento, tuvo poco efecto sobre la productividad y que la crianza de aves a temperatura ambiente alta, no las aclimata para esas condiciones mejor que levantandolas bajo un clima templado.

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Adaptation Climatique De La Poule Pondeuse

Resumé Trois cents poussins femelles d'un jour de souche Warren Isabrown ont été élevés jusqu'à l'âge de 18 semaines dans 3 climats artificiels distincts, respectivement tempéré (20°C, 60% HR), chaud sec (32°C, 40% HR) et chaud humide (32°C, 90% HR). A l'âge de 18 semaines chaque lot d'oiseaux a été divisé en trois et réparti à nouveau en 3 cellules de ponte conditionnées de la même façon que les salles de croissance. Différentes rations alimentaires sont nourries aux oiseaux jusqu'à l'âge de 18 semaines. La consommation d'énergie nécessaire pour produire le même poids vif à 18 semaines a été sensiblement égale dans les 3 climats. L'effet des traitements en période de croissance n'a pas été significativement différent (P>0·05) sur la presque totalité des paramètres étudiés en ponte, exception faite du gain de poids vif 18–38 semaines, des ingérés alimentaires et énérgétiques. Par contre, à l'exception de la maturité sexuelle, tous ces paramètres ont à chaque fois été influencés négativement (P<0·05) par les effets des climats chauds en période de ponte, indépendamment du climat d'élevage. Les résultats de cette expérience semblent indiquer que la température expérimentée pendant les 18 premières semaines après l'éclosion a eu peu d'effet sur la productivité ultérieure, et que l'élevage des oiseaux à hautes températures ambiantes ne leur confère pas une meilleure acclimatation à ces mêmes conditions que lorsqu'ils sont élevés en milieux tempérés.

     

Genotyping of Mycoplasma mycoides subsp. mycoides SC by multilocus sequence analysis allows molecular epidemiology of contagious bovine pleuropneumonia

Mycoplasma mycoides subsp. mycoides SC (MmmSC) is the etiological agent of contagious bovine pleuropneumonia (CBPP). Although eradicated in most developed countries, the disease reappeared in Europe in the 1990s. This reappearance may have been caused either by importation from sub-Saharan Africa, where CBPP is still endemic, or by the reemergence of virulent strains in Europe, as suggested by earlier studies. A multilocus sequence analysis scheme has been developed to address this issue and, most importantly, to be able to monitor new epidemics. The alignment of the full genome sequence of the reference strain PG1 and the partial genome sequence of a pathogenic strain allowed the identification of polymorphic sites. Nineteen initial loci were selected within housekeeping genes, genes of unknown function and non coding sequences. The suitability of these loci for genotyping MmmSC strains was first tested on six strains of diverse geographic origin. The analyses showed that the published PG1 sequence contained a number of specific polymorphisms that were therefore of no use for molecular typing. Among the eight informative polymorphic loci finally selected, only one (ftsY) was positioned within a housekeeping gene. Three main groups and 31 different allelic profiles were identified among 51 strains and strain variants examined. Cluster analysis confirmed that European strains from the 1990s did not originate from Africa. It also showed a genetic link between a European strain isolated in 1967 and those found in southern Africa and Australia. This was in agreement with historical data showing that CBPP was introduced in these regions during colonisation in the 19th century.     

Survey of euthanasia practices in animal shelters in Canada

Questionnaires on methods of euthanasia used in Canadian animal shelters were sent to 196 Canadian animal shelters yielding 67 responses. Sodium pentobarbital injection was the only method of euthanasia used by 61% of establishments that euthanized dogs and 53% of the establishments that euthanized cats. Many of these establishments used pre-medication. Sodium pentobarbital was mostly administered intravenously but some establishments also used intracardiac and intraperitoneal routes, and some only used intracardiac administration for cats. T-61 injection was the only method of euthanasia used by 23% of the establishments that euthanized dogs and 35% of the establishments that euthanized cats. All of these establishments used pre-medication, but the percentages of establishments that only used the intravenous route for administration of T-61 in dogs and cats were 45% and 7%, respectively. Further studies on the use of T-61, and the training and provision of counselling services for staff are recommended.     

Analysis of cellular responses to Mycoplasma mycoides subsp. mycoides small colony biotype associated with control of contagious bovine pleuropneumonia

A better understanding of protective immune memory against contagious bovine pleuropneumonia (CBPP) is needed in order to facilitate the development of safer vaccines based on selected components of the pathogen. For this purpose, cells collected from lymph nodes draining the lungs of Mycoplasma mycoides subsp. mycoides small colony biotype (MmmSC)-infected cattle were stimulated with the pathogen in vitro and evaluated concurrently for proliferation (CFSE based method), expression of activation, memory markers and cytokine production. Direct evidence is presented for a major contribution of CD4+ T cells to the vigorous proliferative and T1 biased cytokine recall responses observed in cattle that have recovered from infection but not in animals developing the acute form of the disease. Two different phenotypes of MmmSC-specific memory CD4 were observed based on CD62L expression and proliferative capacities. Furthermore, recall proliferation of B cells also occurred but was strictly dependent on the presence of CD4. The information provided in this study will facilitate the search for MmmSC antigens that have potential for the development of subunit vaccines against CBPP.     

Economics of Prophylaxis against Peste des Petits Ruminants and Gastrointestinal Helminthosis in Small Ruminants in North Cameroon

Data on reproduction and mortality were collected over one year from 5100 sheep and 13 300 goats in treated and control flocks. The treated animals received vaccination against peste des petits ruminants (PPR) and anthelmintics twice a year. Productivity parameters (fecundity and mortality rates) obtained with and without prophylaxis were fitted into a benefit–cost economic analysis model and run for project lifespans varying from one to five years. At a 7% discount rate, the overall benefits for a project lifespan of five years were estimated as over 15 million FCFA and 11 million FCFA for sheep and goats, respectively. The benefit–cost ratio ranged from 2.26 to 3.27 in goats and 3.01 to 4.23 in sheep, depending on the project lifespan. It was concluded that PPR and gastrointestinal helminthosis are important causes of economic losses in small ruminants in Cameroon. A national or even a regional vaccination campaign against PPR and strategic anthelmintic treatment of small ruminants are recommended.     

Protein supplementation of grazing cattle in the semi-arid zone of Cameroon

Summary The effects of cottonseed meal (CSM) supplementation on forage dry matter intake (FDMI), forage dry matter digestibility (FDMD) and average daily gain (ADG) of steers on pasture in the semi-arid zone of northern Cameroon were evaluated during 120 d in the dry season and the residual effects during 120 d in the rainy season. Thirty steers (229 kg and 2·6 years) were randomly assigned to a complete block design of 3 treatments (0, 0·5 and 1·0 kg of CSM as a protein supplement per steer per day). After feeding CSM to individual steers in the mornings, all were allowed to free graze a pasture ofAndropogon spp. Every month, 2 steers per treatment were put into digestion crates andad lib fed hand-clipped forage of similar botanical composition as that grazed by the remaining steers. Cottonseed meal supplementation increased crude protein absorbed (CPA), rumen turn over rate (RTO) and ADG. Forage intake was increased only with 0·5 kg CSM. Forage dry matter and cell wall (NDF and ADF) digestibility tended to be decreased with 1·0 kg of CSM compared with 0·5 kg or no supplement. Cottonseed meal supplementation during the dry season increased FDMI and RTO, but had no effect on cell wall digestibility, FDMD, CPA and ADG during the rainy season. Data from this study suggest that 0·5 kg of CSM can increase FDMI, RTO, and ADG of cattle during the dry season and that improvement can be maintained throughout the subsequent rainy season.

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Suplementacion Proteica Del Ganado Vacuno En Pastoreo En La Zona Semiarida De Camerun

Resumen Se estudiaron los efectos de la suplementación con pulpa de algodón (CSM) sobre la ingestión de materia seca de forraje (FDMI), la digestibilidad de materia seca de forraje (FDMD) y el crecimiento medio diario (ADG) en terneras en pastoreo en la zona semiárida del norte de Camerún. Los efectos se estudiaron durante 120 días en la estación seca y los efectos residuales durante 120 días en la estación de lluvias. 30 terneras (229 kg y 2·6 a?os) fueron distribuidas al azar segun un dise?o de bloques de 3 tratamientos (0, 0·5 y 1·0 kg de CSM como suplemento proteico por ternera y día). Después de suministrar el suplemento individualmente por las ma?anas, los animales se alimentaron libremente en un pasto deAndropogon supp. Cada dos meses, se colocaron 2 terneras de cada tratamiento en jaulas matabólicas y se alimentaronad libitum con forraje cortado a mano y de una composición botánica similar al consumido por el resto de animales. La suplementación con pulpa de algodón aumentó la absorción de proteína bruta (CPA), la tasa de turnover ruminal (RTO) y al ADG. La ingestión de forraje aumentó sólo con la suplementación de 0·5 kg de CSM. La digestibilidad de la materia seca de forraje y de los componentes de la pared celular (NDF y ADF) tendió a disminuir con la suplementación de 1·0 kg comparada con la de 0·5 kg. La suplementación con pulpa de algodón durante la estación seca aumentó la FDMI y el RTO, pero no tuvo efecto sobre la digestibilidad de los componentes de la pared celular, la FDMD, la CPA y el ADG durante la estación de lluvias. Los resultados de este estudio sugieren que una suplementación de 0·5 kg de CSM puede aumentar la FDMI, la RTO y el ADG del ganado vacuno durante la estación seca y esta majora puede mantenerse durante la estación de lluvias siguiente.

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Apport Nutritif Proteique Chez Le Betail De La Zone Semi Aride Du Cameroun

Résumé Les effets de l’ajout de graines de coton (CSM) sur l’apport en matières sèches de fourrage (FDMI), de la digestibilité en matières sèches de fourrage (FDMD) et sur le gain journalier en poids (ADG) chez des bouvillons sur des pat?rages dans la zone semi-aride du Nord camerounais, furent évalués pendant les 120 jours de la saison sèche. Les effets résiduels furent aussi suivis pendant les 120 jours suivants pendant la saison des pluies. Trente bouvillons (229 kg et 2,6 ans) furent répartis au hasard dans 3 groupes (recevant 0, 0,5 et 1 kg d’apport protéique sous forme de graines de coton par animal et par jour). Après le supplément alimentaire donné le matin, les animaux furent placés sur un pat?rage deAndropogon spp. Tous les moins, 2 animaux par groupe furent ramenés et nourris avec le même fourrage que les autres animaux pouvaient trouver sur les pat?rages. L’apport supplémentaire en CSM augmenta l’absorption protéique (CPA), Le cycle du rumen (RTO) et le taux ADG. L’apport en CSM pendant la saison sèche augmenta les paramètres FDMI et RTO, mais fut sans effet sur la digestibilité des parois cellulaires et des paramètres FDMD, CPA et ADG pendant la saison des pluies. Les résultats de cette étude montrent que l’apport de 0,5 kg de CSM peut augmenter les paramètres FDMI, RTO et ADG chez le bétail et ceci pendant la saison sèche. Cette amélioration étant maintenue tout au long de la saison des pluies.

     

The potential role of an inactivated thermostable vaccine in the control of Newcastle disease in traditionally free-roaming poultry in Central and West Africa

In spite of the clinical and economic importance of Newcastle disease (ND), vaccination of traditional poultry flocks is not a common practice in Cameroon and other countries in West and Central Africa. This study was designed to demonstrate the importance of vaccination against ND and to propose a sustainable vaccination programme with a LaSota strain of NDV vaccine (Multivax) produced in Cameroon. It consisted of field vaccination trials, determination of a strategic vaccination programme through sero-monitoring and assessing vaccine keeping quality under field conditions. Twelve months monitoring of vaccinated flocks revealed that the epidemic periods of March–April and December–January passed without major incidence in flocks. Mortalities were reduced from above 90% in previous years to 10.8% and 24.6% in two experimental sites respectively. Vaccination antibodies were sustained above protection threshold for about 80 days. A booster administered 35 days after the priming dose did not have any effect on declining serum antibodies. The vaccine remained efficacious in eliciting antibody production for up to 10 weeks after initial use and kept at ambient temperature averaging 34°C. For good protection in a less intense vaccination programme, it would be necessary to administer the vaccine one month to the anticipated month of epidemic, thus requiring at least two campaigns per year.     

Post vaccination and colostral peste des petits ruminants antibody dynamics in research flocks of Kirdi goats and Foulbe sheep of north Cameroon

We studied Kirdi goats and Foulbe sheep kept on-station at the Institute of Agricultural Research for Development (IRAD), Garoua to look at their immunological response following vaccination with a specific peste des petits ruminant (PPR) virus vaccine. Pre-vaccination PPR antibody seroprevalences were 44 and 29% in goats and sheep, respectively. Seroprevalences following vaccination were 100% in both species. Titres remained above the protection threshold level (1:10) in both species at 12 months. Maternal antibodies in young animals were detectable to up to 6 months of age but fell below the protection threshold level at 3.5 and 4.5 months in lambs and kids, respectively. Kids and lambs from immunised or exposed dams should be vaccinated at 4 and 5 months of age, respectively.