Evaluation of the supply of Duddingtonia flagrans for the control of gastrointestinal parasites in sheep.

Parasitic resistance imposes alternative control methods, like nematophagous fungi. In this study, two experiments were conducted supplying Duddingtonia flagrans aiming to evaluate the biological control of parasites in sheep. In the first, 24 sheep naturally infected by gastrointestinal nematodes were allocated, in randomized blocks, following the treatments: control or treated group, 0.5g/animal product containing D. flagrans, chlamydospores. Weight, body score, Famacha©, egg count per gram of feces (EPG), and larval percentage were evaluated. In the second experiment, D. flagrans (0.25 and 0.5g product) was infested with manure, plus or not protein concentrate, in a completely randomized design. In both experiments the dose was intentionally lower than recommended. Recovery and larval identification were performed. The SAS analyzed the variables by the MIXED procedure, repeated measures in time. Weight, body score, hematocrit, and Famacha© did not show differences between treatments (p>0.05); however, EPG (p<0.001) and the percentage of larvae identified in coproculture were different. In the second experiment, the inclusion of the fungus did not influence the recovery of larvae (p>0.05). In both experiments, colonization and advancement of the fungus were visualized. Under the experimental conditions, the fungus D. flagrans was not effective in the biological control of parasitic infection in sheep.

Classification Performance of Machine Learning Methods for Identifying Resistance, Resilience, and Susceptibility to Haemonchus contortus Infections in Sheep.

This study investigated the feasibility of using easy-to-measure phenotypic traits to predict sheep resistant, resilient, and susceptible to gastrointestinal nematodes, compared the classification performance of multinomial logistic regression (MLR), linear discriminant analysis (LDA), random forest (RF), and artificial neural network (ANN) methods, and evaluated the applicability of the best classification model on each farm. The database comprised 3654 records of 1250 Santa Inês sheep from 6 farms. The animals were classified into resistant (2605 records), resilient (939 records), and susceptible (110 records) according to fecal egg count and packed cell volume. A random oversampling method was performed to balance the dataset. The classification methods were fitted using the information of age class, the month of record, farm, sex, Famacha© degree, body weight, and body condition score as predictors, and the resistance, resilience, and susceptibility to gastrointestinal nematodes as the target classes to be predicted considering data from all farms randomly. An additional leave-one-farm-out cross-validation technique was used to assess prediction quality across farms. The MLR and LDA models presented good performances in predicting susceptible and resistant animals. The results suggest that the use of readily available records and easily measurable traits may provide useful information for supporting management decisions at the farm level.

Phenotypical categorization of indigenous ewes as resistant, resilient or susceptible to Haemonchus contortus.

The economic losses caused by parasite infections, aggravated by resistance to anthelmintics, have generated demand for alternatives involving non-chemical control, such as the selection of resistant animals. The objective of this study was to identify which characteristics best describe animals that are resistant, resilient or susceptible to Haemonchus contortus and estimate the percent number in each category. Sixty-one Morada Nova ewes were evaluated in an extensive system. The performance variables (weight, body condition score), hematological variables (packed cell volume, hemoglobin, white blood cells, segmented neutrophils, lymphocytes, eosinophils, monocytes) and fecal egg counts were measured individually every 14 days during 6 months. The variables were transformed, and analysis of variance was carried out, with construction of a correlation network. Characteristics linked to parasite infection showed variations among the categories, which helped to identify sheep resistant, resilient or susceptible to H. contortus. Based on the analyses performed, 88.3% of the animals were resistant or resilient and only 11.7% were susceptible. Presence of Trichostrongylidae eggs, body condition score, packed cell volume (PCV) and eosinophil counts were found to be good indicators of naturally infected ewes, and there were significant differences between the categories and correlations between the traits.

Growth performance, carcass traits and meat quality of lambs fed increasing level of Macadamia nut cake.

A total of 40 lambs were divided into four different treatments according to the inclusion level of the macadamia nut cake: C-control (0%), M1 (6.5%), M2 (12%) and M3 (20%). Feed was provided twice a day; animal weighing along with body condition scoring occurred within a 14-day interval. The lambs were slaughtered at the end of the performance test. Analysis of variance was performed through the Mixed procedure of the SAS, as well as linear and quadratic regression analysis. The groups presented differences between the treatments (P <0.05) for dry matter intake (DMI), ethereal extract intake (EEI), consumption in relation to live weight percentage and feed conversion ratio (FCR). The lowest mean DMI was obtained by the animals that received the M2 and differed from the C treatment, whose average was the highest. The EEI was highest for the M3 group and the FCR was also better for this group. There was a linear effect for EEI and FCR, and quadratic for crude protein intake. There was no effect for carcass characteristics, and only initial pH had a decreasing linear effect. The macadamia nut cake was effective in promoting the performance of the animals, since there was an improvement in feed conversion.

The effects of genetic group and sex on residual feed intake, performance, morphometric, testicular, and carcass traits' in lambs.

The aim of this study was to analyze the effects of genetic group and sex on residual feed intake, performance, testicular size, carcass and morphometric traits in Santa Ines purebred and Dorper ´ Santa Ines crossbred lambs. A total of 32 lambs, with initial body weight of 18±3.7 kg were used. Analysis of variance, considering the interaction between sex and genetic group of all the traits were performed. Crossbred females (-0.018±0.06) and purebred males (-0.018±0.05) were more efficient (p<0.001) in residual feed intake than crossbred males (0.018±0.04) or purebred females (0.018±0.04). The most efficient animal in residual feed intake consumed 37.9% less feed (1.179 kg/day) than the least efficient animal (1.899 kg/day). Crossbred, when compared to purebred, showed higher values for body weight, average daily gain, testicle size, carcass traits; had greater muscle accumulation, were more compact and with more aptitude to beef. Purebred were taller, but with lower body length and thoracic perimeter than crossbred. Males had greater muscle accumulation, were more compact and with more aptitude to meat. Crossing of native (Santa Ines) with exotic breed (Dorper) is an alternative to align efficiency in feed use, testicular size, compactness, aptitude for meat and ability for muscle accumulation.

Hematological, parasitological and biochemical parameters in sheep during the peripartum period / Parámetros hematológicos, parasitológicos y bioquímicos en ovejas durante el periparto / Parâmetros hematológicos, parasitológicos e bioquímicos de ovelhas durante o periparto

Abstract Background: Pregnancy in all animal species requires special care and attention. During this period there is great variation in hematological and biochemical parameters. Many times these parameters are misinterpreted as being obtained from non-pregnant animals with unknown parasite status. Objective: To characterize the hematological, biochemical, and parasitological values within the peripartum period of Santa Ines sheep naturally infected. Methods: For this purpose, 45 ewes were used, with an average body weight of 50 kg. Data were collected during pregnancy, birth and, lactation. Measurements included body weight, body condition score (BCS), evaluation of conjunctive staining, and collection of blood and feces. Results: All variables changed throughout physiological stages. Weight and BCS were different between periods (p<0.05). Fecal egg counts (FEC) were higher in the peripartum period, with a predominance of Haemonchus ssp, 92.85%. Mean hematological and biochemical values varied throughout the study, (p>0.05). Conclusion: The influence of peripartum on the parameters studied should be considered and its use as a reference value. Regarding the physiological variations observed during peripartum, proper animal management could help minimizing the negative effects of parasitic infections on productivity.

Resumen Antecedentes: La preñez en todas las especies animales requiere atención y cuidados especiales. En ese período existe gran variación en los parámetros hematológicos y bioquímicos. Muchas veces estos parámetros son interpretados erróneamente por ser obtenidos de animales no gestantes y con estatus parasitario desconocido. Objetivo: Caracterizar los valores hematológicos, bioquímicos y parasitológicos durante el periparto en ovejas Santa Inés infectadas naturalmente. Métodos: Se utilizaron 45 ovejas, con un peso corporal promedio de 50 kg. la recolección de muestras se realizó durante la gestación, el parto y la lactancia. Se evaluó el peso, la condición corporal, la tinción conjuntiva, y se recolectaron muestras de sangre y heces. Resultados: Todas las variables mostraron variaciones a lo largo de las etapas fisiológicas. La puntuación de peso y condición corporal (BCS) mostró diferencia entre períodos (p<0,05). Los recuentos de huevos fecales (FEC) tuvieron mayores promedios en el periparto, con predominio de Haemonchus ssp, 92,85%. Los valores medios hematológicos y bioquímicos variaron a lo largo del estudio (p<0,05). Conclusiones: Se recomienda considerar la influencia del periparto en los parámetros estudiados y su uso como valor de referencia. Con respecto a las variaciones fisiológicas observadas durante el periparto, el manejo adecuado de los animales podría ayudar a minimizar los efectos negativos de las infecciones parasitarias sobre la productividad.

Resumo Antecedentes: A prenhez em todas as espécies requer atenção e cuidados especiais. Neste período há grande variação dos parâmetros hematológicos e bioquímicos dos animais. Muitas vezes estes parâmetros são mal interpretados na realização de diagnósticos por serem baseados em parâmetros de animais saudáveis não gestantes, desconsiderando também a infecção parasitária. Objetivo: Caracterizar os valores hematológicos, bioquímicos e parasitológicos durante o periparto de ovelhas da raça Santa Inês naturalmente infectadas. Métodos: Foram utilizadas quarenta e cinco ovelhas, com peso corporal médio de 50 kg, os animais foram acompanhados durante a prenhez, parto e lactação. As análises compreendiam: pesagem, condição corporal, Famacha©, sangue e fezes. Resultados: Todas as variáveis apresentaram variações concomitantemente ao avanço da gestação, parto e lactação. O peso (PS) e o escore da condição corporal (ECC) apresentaram diferença estatística entre os períodos (p>0,05). As contagens de ovos por grama de fezes (FEC) apresentaram médias mais elevadas no periparto. Os valores hematológicos e bioquímicos também variaram (p>0,05). Conclusão: Devido ao resultado, sugere-se considerar a influência de periparto sobre os parâmetros estudados e a sua utilização como um valor de referência. Tendo em vista as variações fisiológicas devido o período do periparto e as infecções parasitárias o manejo dos animais deve ter como objetivo minimizar os impactos negativos na produção animal.