Performance of three tropical hair sheep breeds.

The performance of three hair sheep breeds (Brazilian Somali, Morada Nova, and Santa Ines) was evaluated in the production environment of northeastern Brazil. Data from a total of 524 lambs sired by 21 rams and out of 190 ewes were analyzed. These data were collected from 1980 to 1983 at Sobral, Brazil from an experiment designed to compare performance of the three breeds. The traits included weights of lambs at birth, weaning, 8 mo, 10 mo, and yearling ages and ewe characters of weight at lambing (EWT), total lamb weight born (LWB), total lamb weight weaned (LWW), and prolificacy rate (PR). Differences (P < .01) among breeds were found for all characters. The Brazilian Somali, the smallest and slowest-gaining breed, was less sensitive to yearly variation than were the other breeds. The Santa Ines, the largest and fastest-gaining breed, was superior in LWB and LWW per ewe lambing. Averaged over the 4-yr period, the Morada Nova had the highest PR (1.82), and the Brazilian Somali and Santa Ines had similar PR (1.39 and 1.31, respectively). Environmental effects on PR due to yearly rainfall quantity and distribution pattern influenced lamb growth up to weaning and ewe reproduction performance. Breed x year (P < .05) interaction effects on PR were largely attributable to the Somali breed's exhibiting higher PR than the Santa Ines and Morada Nova breeds during the relatively wet years of 1981 and 1982.     

Evaluation of sheep breeds for early growth in tropical north-east Brazil

Summary Three breeds of sheep, Brazilian Somali, Morada Nova and Santa Inês which are indigenous to hot tropical semi-arid north-east Brazil were studied for their early growth. There were large breed differences in size at birth, at the 86th day and at 6 months. The Santa Inês was the largest and the Brazilian Somali the smallest. The type of birth (single vs. multiple) had a profound effect on weight at virtually all stages of growth which was similar for male and female lambs. Sex effects tended to become significant at around the 86th day, female lambs slightly outweighing males but marked sex differences appeared around 6 months when males outweighed females. The 7-day variation in age of lambs when the weights were taken around the 15th day had a marked effect on weight and correction for age would be necessary in future studies. However, the 7-day variation in age around the 86th day and thereafter did not affect the weights. The birth weight and weights at the 15th, 86th and 112 days and at 6 months were significantly correlated.

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Evaluacion De Razas Ovinas Durante Su Crecimiento En La Nordeste Tropical De Brasil

Resumen Se realizó una evaluación de crecimiento precoz de tres razas nativas, Somali Brasilera, Morada Nova, y Santa Inés, razas que habitan la parte nordeste tropical semiárida de Brasil. Se encontraron diferencias marcadas en tamaño al nacer, a los 86 días y a los 6 meses. La Santa Inés fué la más grande y la Somali Brasilera la más pequeña. El tipo de parto (simple-multiplo) tuvo un afecto marcado en el peso virtualmente en todos los estados de crecimiento, efecto que fué similar en hembras y machos. Los efectos de sexo comenzaron a ser significativos alrededor del día 86, lashembras pesaron un poco más que los machos, pero los machos pesaron significativamente más que las hembras alrededor de los 6 meses. Los 7 días de diferencia en edad, cuando los borregos se pesaron alreadedor de los 15 días, tuvieron un efecto marcado, teniendo que hacer correcciones en el futuro. Este efecto no se detectó cuando se pesaron a los 86 días y posteriormente. Los pesos al nacer y el peso a los 15, 86 y 112 días y a los 6 meses se correlacionaron significativamente.

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Evaluation Des Facultés De Developpement Chez Diverses Races De Mouton Dans Le Nord Est Du Brésil

Résumé Trois troupeaux de moutons de races indigènes Somali Brésilien, Morada Nova et Santa Inès adaptées au climat tropical chaud semi-aride du Nord Est du Brésil ont été comparativement étudiés au niveau de leur croissance précoce. On a observé de grandes différences raciales de taille à la naissance, au 86e jour et à 6 mois. Les Santa Inès ont été les plus développés et les Somali brésiliens plus petits. Le type de naissance (gestation simple ou gestation multiple) a eu un effet considérable sur le poids à virtuellement tous les stades de développement, qui a été semblable pour les agneaux mâles et femelles. L'effet du sexe tend à devenir significatif aux alentours du 86e jour, les femelles devenant un peu plus légeres que les mâles aux environs du 6e mois, la différence entre les sexes est plus marquée lorsque les mâles deviennent plus lourds que les femelles. Des variations de 7 jours dans l'âge des agneaux lorsque les poids ont été pris vers le 15e jour ont eu une influence marquée sur les poids et des corrections relatives à l'âge seraient nécessaires lors d'études ultérieures. Quoiqu'il en soit cette variation de 7 jours dans l'âge n'affecte pas les poids lors des pesées au 86e jour ni après. Les poids de naissance et ceux relevés les 15e, 86e et 112 jours ainsi qu'à 6 mois ont des corrélations significatives.

     

Evaluation of the sedative and cardiorespiratory effects of dexmedetomidine,dexmedetomidine-butorphanol,and dexmedetomidine-ketamine in cats

OBJECTIVE: To determine sedative and cardiorespiratory effects of dexmedetomidine alone and in combination with butorphanol or ketamine in cats. DESIGN: Randomized crossover study. ANIMALS: 6 healthy adult cats. PROCEDURES: Cats were given dexmedetomidine alone (10 microg/kg [4.5 mg/lb], IM), a combination of dexmedetomidine (10 microg/kg, IM) and butorphanol (0.2 mg/kg [0.09 mg/lb], IM), or a combination of dexmedetomidine (10 microg/kg, IM) and ketamine (5 mg/kg [2.3 mg/lb], IM). Treatments were administered in random order, with > or = 1 week between treatments. Physiologic variables were assessed before and after drug administration. Time to lateral recumbency, duration of lateral recumbency, time to sternal recumbency, time to recovery from sedation, and subjective evaluation of sedation, muscle relaxation, and auditory response were assessed. RESULTS: Each treatment resulted in adequate sedation; time to lateral recumbency, duration of lateral recumbency, and time to recovery from sedation were similar among treatments. Time to sternal recumbency was significantly greater after administration of dexmedetomidine-ketamine. Heart rate decreased significantly after each treatment; however, the decrease was more pronounced after administration of dexmedetomidine-butorphanol, compared with that following the other treatments. Systolic and diastolic blood pressure measurements decreased significantly from baseline with all treatments; 50 minutes after drug administration, mean blood pressure differed significantly from baseline only when cats received dexmedetomidine and butorphanol. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that in cats, administration of dexmedetomidine combined with butorphanol or ketamine resulted in more adequate sedation, without clinically important cardiovascular effects, than was achieved with dexmedetomidine alone.     

Canine visceral leishmaniasis: relationships between clinical status, humoral immune response, haematology and Lutzomyia (Lutzomyia) longipalpis infectivity

The main source of Leishmania infantum infection in humans is a naturally infected dog. This study reports on the infectivity to phlebotomine sandflies (Lutzomyia longipalpis) of serologically positive mongrel dogs that differed in clinical status, haematology and humoral responses to immunoglobulin (Ig) G(T) (total anti-Leishmania IgG), IgG(1) and IgG(2) subclasses of antibody to crude antigen of L. infantum. Forty-five female L. longipalpis were allowed to feed directly on the ears of dogs classified as asymptomatic, oligosymptomatic or symptomatic before being dissected five days later. Promastigotes were detected in 88% of the dissected sandflies. The highest rate of infectivity to sandflies was found in symptomatic dogs, followed by oligosymptomatic and asymptomatic animals. The results suggest that dogs naturally infected with L. infantum with higher total IgG and IgG(2) concentrations and lower haematocrit levels were able to infect the highest proportion of L. longipalpis. No correlation was observed between anaemia and the intensity of clinical signs. Symptomatic dogs presented the highest infection rate and intensity of infection.     

Antimicrobial effect against different bacterial strains and bacterial adaptation to essential oils used as feed additives

The aim of this study was to evaluate the antimicrobial activity and determine the minimum bactericidal concentration (MBC) of the essential oils derived from Origanum vulgare (oregano), Melaleuca alternifolia (tea tree), Cinnamomum cassia (cassia), and Thymus vulgaris (white thyme) against Salmonella Typhimurium, Salmonella Enteritidis, Escherichia coli, Staphylococcus aureus and Enterococcus faecalis. The study also investigated the ability of these different bacterial strains to develop adaptation after repetitive exposure to sub-lethal concentrations of these essential oils. The MBC of the essential oils studied was determined by disc diffusion and broth dilution methods. All essential oils showed antimicrobial effect against all bacterial strains. In general, the development of adaptation varied according to the bacterial strain and the essential oil (tea tree > white thyme > oregano). Therefore, it is important to use essential oils at efficient bactericidal doses in animal feed, food, and sanitizers, since bacteria can rapidly develop adaptation when exposed to sub-lethal concentrations of these oils.     

Seasonal leaf dynamics in an Amazonian tropical forest

The ecological consequences of climate change for large tropical forests such as the Amazon are likely to be profound. Amazonian forests strongly influence regional and global climates and therefore any changes in forest structure, such as deforestation or die-back, may create positive feedback on externally forced climate change. Monitoring, modelling and managing the impacts of anthropogenic climate change on forest dynamics is therefore an important objective of forest researchers, and one that requires long-term data on changes at the level of community, populations and phenotypes. In this paper we provide the most comprehensive study yet on the seasonal dynamics of various leaf traits: leaf area index (LAI), leaf mortality (LM), leaf biomass (LB), leaf growth rate (LG), and leaf residence time (TR) from 50 experimental plots in a forest site at Belterra, Pará State, Brazil. From this study we estimate annual mean leaf area index (LAI) to be 5.07 m² m⁻² and annual mean leaf dry biomass to be 0.621 kg m⁻². The typical leaf grew at 0.049 kg m⁻² month⁻¹ and remained on the tree for 12.7 months. We compare these results to other similar studies and critically discuss the factors driving leaf demographics in Amazonia.     

Efficacy of adding chemical and microbial additives to silage on beef cattle performance: Systematic review and meta-analysis

The effects of different additives on farm-scale silage quality and beef cattle performance are inconsistent. This study aimed to carry out a systematic review and meta-analysis to evaluate the efficacy of chemical and microbial additives to silage on beef cattle performance. Systematic searches were performed using databases and scientific journals, and 42 articles were selected. Data for all variables were grouped into subgroups according to the additive type. For dry matter intake and average daily gain, the data were also grouped by forage type due to greater comparison numbers. The treatment mean differences and 95% confidence intervals (p < 0.05) were analysed using a random-effects model. The use of homo- and heterofermentative microbial inoculant mixtures and chemical additives (Ch) increased the average daily gain of beef cattle fed maize/sorghum silage. Homofermentative microbial inoculant (Ho), Ch, and a mixture of microbial inoculant and chemical additives also increased the average daily gain of beef cattle fed temperate grasses. Only Ch increased dry matter intake. Ch increased feed efficiency, and Ch and Ho increased carcass weight. The evaluated additives improved the silage fermentation process mainly via pH and ammonia nitrogen reduction. Overall, this meta-analysis demonstrated that silage additives improved the ensiling process and beef cattle performance, with better results with Ch use. Due to the aerobic stability and microbiological profile analyses being carried out more in laboratory-scale silos, more studies are needed to determine these silage parameters after opening the silo at the farm scale.     

Oral and parenteral vaccines against <Emphasis Type="Italic">Flavobacterium columnare</Emphasis>: evaluation of humoral immune response by ELISA and in vivo efficiency in Nile tilapia (<Emphasis Type="Italic">Oreochromis niloticus</Emphasis>)

Flavobacterium columnare is a bacterial pathogen for many freshwater fish species. It is responsible for outbreaks in fish farms worldwide, causing high mortality rates. Fish vaccination is a potential approach for prevention and control of disease, with oral vaccines suitable for fish because of their easier application, low cost and minimum stress to fish. Alginate microparticles have been widely used as controlled release systems, including for fish vaccination. The aim of this study was to evaluate the capacity of oral and parenteral vaccines against F. columnare to induce a humoral response, as well as the in vivo efficiency in Nile tilapia fingerlings. The fingerlings were immunized with bacterin by intraperitoneal (i.p.), intramuscular (i.m.), oral and immersion routes, as well as orally with alginate microparticles containing formalin-killed bacteria. A sandwich ELISA was developed to detect specific antibodies against F. columnare. The animals were challenged with pathogenic strain BZ-1 to determine the relative percentage of survival. A significant humoral response was induced by bacterin administered by i.p. and i.m. routes (P < 0.05). However, none of the vaccine preparations were effective in protecting fish against F. columnare infection (P < 0.05). In spite of high antibody levels, there was no relation between immunoglobulin titers and resistance to columnaris for Nile tilapia fingerlings. These data suggest that use of serological analysis as the only method to determine vaccine efficiency against F. columnare infection in Nile tilapia can lead to imprecise results for the usefulness of these products in vivo.     

Effect of starvation during late megalopa stage of Mithraculus forceps (Brachyura: Majidae) on larval duration, synchronism of metamorphosis, survival to juvenile, and newly metamorphosed juvenile size

Larval resistance to temporary starvation is considered a key factor for successful development in the wild. Subjecting larvae to temporary starvation during early and/or late development is occasionally used in larviculture to reduce production costs.Mithraculus forceps is a popular species in the marine aquarium industry for their ability to control nuisance algae in aquarium tanks; a larval culture methodology was previously proposed in order to avoid collection from the wild. In an attempt to reduce production/feeding costs of M. forceps larval culture (two zoea stages and a megalopa), larvae (megalopa stage) were starved after 7 and 8 days post-hatch (DPH); starvation treatments were compared with those of the control treatment where larvae were fed continuously. No differences were found in survival to juvenile, metamorphosis synchronism or larval duration between the treatments, which suggest that at least by day 7 DPH, megalopae have already achieved the point-of-reserve-saturation (PRS) and are able to successfully metamorphose to crab stage without feeding (facultative lecithotrophic); newly metamorphosed juveniles are slightly smaller (particularly the ones starved after 7DPH). This flexible way of development might be very advantageous in the wild and might allow the reduction of costs of larval culture in captivity.     

Reproductive cycle of the Amazonian planktivorous catfish Hypophthalmus marginatus (Siluriformes,Pimelodidae)

We evaluated the annual process of oocyte and ovarian development of the planktivorous Amazonian catfish, the mapará (Hypophthalmus marginatus), aiming to support captive reproduction for domestication. A total of 149 females were captured from the Tocantins River at the Tucuruí Dam (3°49'55"S, 49°39'9"W) in 13 sampling events. For each individual, we evaluated ovary histology and plasma steroid concentrations. Two annual reproductive cycles, with similar characteristics, including a long period of rest, a short vitellogenic stage and a well‐defined spawning season from November to March, were described. A 17β‐estradiol (E₂) rise and a 17α,20β‐dihydroxy‐4‐pregnen‐3‐one (DHP) peak were associated with vitellogenesis and spawning season, respectively, in the first cycle but not in the second reproductive cycle. In conclusion, the studied species presents a reproductive cycle similar to that of other migratory total spawners; however, unusually for this group of fish, there were three (but not two) batches of vitellogenic oocytes in “in maturation” and “mature” stage ovaries, pointing to the possibility of more than one spawn during the spawning season.