Abstract The objective of this work was to determine the effect of solar radiation intensity of the grazing system on sheep behavior. Treatment 1, consisted of monoculture of natural grasses (47 ± 5 lux), treatment 2 of natural grasses with Leucaena leucocephala trees (34 ± 3 lux) and treatment 3 of natural grasses with Manguifera indica trees (16 ± 3 lux). The total time of each activity per daily session was determined. A completely randomized design was used with a 3x2 factorial arrangement (three intensities of solar radiation, two sessions per day). Grazing behavior was affected by the interaction between factors. The grazing-walking activity was higher in the pastures with lower levels of solar radiation (Leucaena y Manguifera), with 217.50 y 216.38 min, respectively, in the morning session, while all times were lower in the afternoon session, with the lowest result in grazing in the sun (108.05 minutes). The reduction of solar radiation under the treetops favored the behavior of the sheep, which allowed the animals to perform resting and ruminating activities under the shade of the trees, more preferably in the afternoon session.

Resumen El objetivo fue determinar el efecto de la intensidad de radiación solar del sistema de pastoreo en la conducta de ovinos. El tratamiento 1 consistió en: monocultivo de gramíneas naturales (47 ± 5 lux); el 2: gramíneas naturales con árboles de Leucaena leucocephala (34 ± 3 lux); y el 3: gramíneas naturales con árboles de Manguifera indica (16 ± 3 lux). Se determinó el tiempo total de cada actividad por sesión del día. Se utilizó un diseño completamente aleatorizado, con arreglo factorial 3x2 (tres intensidades de radiación solar por dos sesiones del día). La conducta en pastoreo fue afectada por la interacción entre los factores. La actividad pastar-caminar fue mayor en los pastoreos de menor nivel de radiación solar (Leucaena y Manguifera) con 217.50 y 216.38 min respectivamente, en la sesión de la mañana; mientras que todos los tiempos fueron menores en la sesión tarde, con el menor resultado en el pastoreo al sol (108.05 minutos). La reducción de la radiación solar bajo la copa de los árboles favoreció el comportamiento conductual de las ovejas, esto permitió que los animales realizaran actividades de descanso y rumia bajo la sombra de los árboles, con más preferencia en la sesión tarde.

ABSTRACT The aim of this study was to evaluate the haematological parameters of adult Pelibuey sheep under conditions of the humid tropics of Mexico. Erythrocytes (RBC, x106/µL), haemoglobin (HB, g/dL), haematocrit (HTO, %), mean corpuscular volume (MCV, fL), mean corpuscular haemoglobin (MCH, pg), and mean corpuscular haemoglobin concentration were analysed. (MCHC, g/dL), leukocyte count (WBC, x103/µL) and platelets (PLT, x103/µL) through descriptive statistics of 86 adult, non-pregnant, non-lactating sheep. The values were: RCB 10.35±1.08 x106 /µL; HB 10.83 ± 1.53 g/dL, HTO 33.97 ± 3.79%, MCV 32.78 ±2.49 fL, MCH 10.63 ±1.16 pg, MCHC 32.55 ±3.35 g/dL, WBC 10.75 ±5.78 x103/ µL, PLT 340±658 x103/µL. The haematological parameters obtained are within the average values of the species.

RESUMEN El objetivo del estudio fue evaluar los parámetros hematológicos de ovejas Pelibuey adultas bajo condiciones del trópico húmedo de México. Se analizaron eritrocitos (RBC, x106 /µL), hemoglobina (HB, g/dL), hematocrito (HTO, %), volumen corpuscular medio (VCM, fL), hemoglobina corpuscular media (HCM, pg), concentración de hemoglobina corpuscular media (CHCM, g/dL), conteo de leucocitos (WBC, x103 /µL) y plaquetas (PLT, x103 /µL) a través de estadística descriptiva de 86 ovejas adultas, no gestantes no lactantes. Los valores fueron: RCB 10.35±1.08 x106 /µL; HB 10.83 ±1.53 g/dL, HTO 33.97±3.79%, VCM 32.78 ±2.49 fL, HCM 10.63±1.16 pg, CHCM 32.55 ±3.35 g/dL, WBC 10.75 ±5.78 x103 /µL, PLT 340±658 x103 /µL. Los parámetros hematológicos obtenidos se encuentran dentro de los valores medios de la especie.

RESUMO: Nos sistemas tradicionais de produção de ovinos em regiões tropicais, a avaliação e monitoramento do crescimento dos animais não são práticas comuns. Isso se deve principalmente à adoção limitada de tecnologia e aos altos custos associados à aquisição de balanças para animais. O presente estudo teve como objetivo desenvolver equações para prever o peso corporal (PC) de borregas Pelibuey usando uma fórmula de Volume Corporal (VC). Foram obtidos dados de PC e VC de 85 borregas. Os modelos avaliados foram os seguintes: 1) linear, 2) quadrático, 3) cúbico, 4) alométrico, 5) exponencial e 6) logarítmico. Além disso, a capacidade preditiva dos modelos para o PC foi avaliada por meio de validação cruzada k-fold (k=10). O PC e VC foram 20,60 ± 8,73 kg e 17,54 ± 7,89 dm3, respectivamente. O modelo quadrático apresentou o maior r2 e os menores valores de erro do quadrático médio, raiz do erro do quadrático médio e critério de informação bayesiano, enquanto a técnica de validação cruzada k-fold também teve o maior r2 e os menores valores de erro quadrático médio de predição e erro médio absoluto. O modelo quadrático foi o melhor desempenho matemático para predizer o PC de cordeiras Pelibuey em crescimento usando o VC. RESUMO tropicais comuns (PC . (VC) 8 seguintes 1 linear 2 3 cúbico 4 alométrico 5 6 logarítmico disso kfold k fold k=10. k10 k=10 10 (k=10) 2060 20 60 20,6 873 73 8,7 1754 17 54 17,5 789 7 89 7,8 dm3 dm respectivamente r bayesiano absoluto (VC k1 k=1 (k=10 206 20, 87 8, 175 17, 78 7, k= (k=1 (k= (k

ABSTRACT: In traditional sheep production systems in tropical regions, the evaluation and monitoring of animal growth are not commonly practiced. This is primarily attributed to the limited adoption of technology and the high costs associated with acquiring livestock scales. The present study developed equations to predict body weight of Pelibuey ewe lambs using a Body Volume (BV) formula. BW and BV were obtained from 85 ewe lambs. The models evaluated were as follows: 1) linear, 2) quadratic, 3) cubic, 4) allometric, 5) exponential and 6) logarithmic. In addition, the models’ predictive ability for BW was assessed by k-fold (k=10) cross-validation. The BW and BV were 20.60 ± 8.73 kg and 17.54 ± 7.89 dm3, respectively. The quadratic model showed the highest r2 and the lowest values of mean square error, root mean square error, and bayesian information criterion, while the k-fold cross-validation technique also had the highest r2 and the lowest values of mean squared prediction error and mean absolute error. The quadratic model was the best performing mathematical model for predicting BW of growing Pelibuey ewe lambs using BV. ABSTRACT regions practiced scales (BV formula 8 follows 1 linear 2 3 cubic 4 allometric 5 6 logarithmic addition kfold k fold k=10 k10 10 (k=10 crossvalidation. crossvalidation cross validation. validation 2060 20 60 20.6 873 73 8.7 1754 17 54 17.5 789 7 89 7.8 dm3 dm respectively r criterion k=1 k1 (k=1 206 20. 87 8. 175 17. 78 7. k= (k= (k

ABSTRACT Objective. To evaluate the influence of lutropin alfa (recombinant human LH, r-hLH) administered at 12 and 24 h post progesterone device withdrawal (CIDR) on the response of hours to onset of estrus (OE), ovulatory rate (OR), unfertilized oocytes (UNO), transferable embryos (TE), quality 1 embryos (Q1E) and plasma LH levels, in a pFSH-based superovulation protocol in Pelibuey sheep. Materials and methods. Eighteen Pelibuey sheep were used and randomly distributed into three groups (n=6): T1 (200 mg FSHp-Folltropin®); T2 (200 mg FSHp + 75 IU r-hLH at 12 h post CIDR withdrawal) and T3 (200 mg pFSH + 75 IU r-hLH at 24 h post CIDR withdrawal). Results. No significant differences were found between OE and OR. UNO was higher (p<0.05) in T2 (5.0±2.3) compared to T1 (0.8±0.6) and T3 (1.3±0.7). The number of Q1E was higher (p<0.05) in T3 (3.1±1.1) compared to T1 (1.1±0.3) and T2 (0.6±0.5) and for TE was higher (p<0.05) for T3 (6.6±0.9) relative to T2 (2.0±1) and T1 (4.0±0.6). Conclusions. The application of r-hLH 24 h after removal of CIDR increases plasma LH levels, in effect, decreasing the amount of UNO, improving the quantity and quality of TE in Pelibuey sheep.

RESUMEN Objetivo. Evaluar la influencia de lutropina alfa (LH recombinante humana, r-hLH) administrada a 12 y 24 h post-retiro del dispositivo de progesterona (CIDR) en la respuesta de horas al inicio del estro (IE), tasa ovulatoria (TO), ovocitos no fertilizados (ONF), embriones transferibles (ET), embriones calidad 1 (EC1) y niveles plasmáticos de LH, en un protocolo de superovulación a base de FSHp en ovejas Pelibuey. Materiales y métodos. Se utilizaron 18 ovejas de la raza Pelibuey, las cuales fueron distribuidas al azar en tres grupos (n=6): T1 (200 mg FSHp-Folltropin®); T2 (200 mg FSHp + 75 UI r-hLH a 12 h post-retiro del CIDR) y T3 (200 mg pFSH + 75 UI r-hLH a 24 h post-retiro del CIDR). Resultados. Horas del IE y TO no se encontraron diferencias significativas. En ONF fue mayor (p<0.05) en T2 (5.0±2.3) en comparación con T1 (0.8±0.6) y T3 (1.3±0.7). El número de EC1 fue mayor (p<0.05) en T3 (3.1±1.1) comparado con T1 (1.1±0.3) y T2 (0.6±0.5) y para ET fue mayor (p<0.05) para T3 (6.6±0.9) en relación a T2 (2.0±1) y T1 (4.0±0.6). Conclusiones. La aplicación de r-hLH a 24 h de retirado el CIDR incrementa los niveles plasmáticos de LH, en efecto, se disminuye la cantidad de ONF, se mejora la cantidad y calidad de ET en ovejas de la raza Pelibuey.

ABSTRACT Background: Cuba’s subtropical climate favors the circulation of agents that cause gastroenteric parasitic diseases, a serious health problem in sheep raising. Aim. To determine the relationship between hematologic variables and the parasitic burden on different farms. Materials and methods: This research study took place between January and June 2021. A total of 294 adult Pelibuey sheep were included in the study, all of which had a coprological test, hemogram, and differential. One-way ANOVA was used to study the variables per production unit. HSDTukey multiple comparison test was used as well. Pearson correlation was performed to determine the relationship between the variables included; the hematological variables with the greatest impact on parasites were compared. Results: The animals were considered resilient, since their hematological values were within the normal ranges, despite the different parasitic burdens with Haemonchus contortus. The correlation analysis of highly parasitized animals showed a positive correlation between the corpuscular hemoglobin concentration mean (CHCM) and the hemoglobin concentration (r’=0.812**). The Hb concentration showed a positive correlation with the hematocrit (Ht) (r=0.775**), whereas the eggs per feces gram test was negative (r= -0.430**). Conclusions: The correlation coefficient for hemoglobin, hematocrit, mean corpuscular hemoglobin concentration, lymphocytes, and neutrophils was more visible in the animals infested with a parasitic burden below 800 eggs per gram.

Resumen Antecedente: El clima subtropical de Cuba, permite durante todo el año, la circulación de los agentes causales de las enfermedades parasitarias gastroentéricas; que constituyen un grave problema de salud en las explotaciones ovinas. Objetivo. Determinar la relación entre variables hematológicas y la carga parasitaria en las distintas unidades de producción estudiadas. Materiales y métodos: La investigación se llevó a cabo durante el período de enero a junio de 2021. Se trabajó con una masa ovina total de 294 animales adultos de la raza Pelibuey, a los que se les realizó examen coprológico y hemograma con diferencial. Para comparar las medias de las variables estudiadas por unidades de producción se utilizó el método de ANOVA simple y la prueba de comparación múltiple de HSD Tukey. Se aplicó la correlación de Pearson para determinar la relación entre las variables estudiadas y se compara las variables hematológicas de mayor impacto con la carga parasitaria. Resultados: Se consideran como animales resilientes, donde los valores hematológicos se encuentran dentro de rangos normales a pesar de tener diferentes de cargas parasitarias con Haemonchus contortus. Es de destacar que en el análisis de correlación de los animales con carga parasitaria alta se encontró que existe una correlación positiva entre la concentración de hemoglobina corpuscular media (CHCM) y la concentración de hemoglobina (r’=0.812**). La concentración de la (Hb) presentó una correlación positiva con el hematocrito (Hto), donde (r=0.775**); mientras que con el HPG (prueba de huevos por gramos de heces) fue negativa (r= -0.430**). Conclusiones: El coeficiente de correlación para hemoglobina, hematocrito, concentración de la hemoglobina corpuscular media, linfocitos y neutrófilos se hacen más evidentes en animales infestados con carga parasitaria menor de 800 huevos por gramos.

Abstract Ovine pulmonary adenocarcinoma is a transmissible pulmonary malignancy of sheep caused by a beta-retrovirus currently named Jaagsiekte sheep retrovirus (JSRV). Club cells (formerly Clara cells) in the bronchiole and type II pneumonocytes in the alveoli are the target oncogenic cells for this virus. Characterized clinically by intermittent cough, abundant nasal discharge, and progressive weight loss, the tumors randomly involve all lung lobes or have a cranioventral distribution mimicking bronchopneumonia. The definitive diagnosis of ovine pulmonary adenocarcinoma requires identifying Jaagsiekte sheep retrovirus or associated specific proteins in neoplastic cells such as JSRV-Env oncogenic protein. A two-year-old Male Pelibuey sheep with a history of chronic cough and progressive weight loss was treated unsuccessfully with antibiotics and died a few days later. Postmortem examination revealed lung edema and several nodular to locally extensive masses in the lungs. Microscopically the tumoral tissues were composed of clusters of neoplastic epithelial cells exhibiting a lepidic growth pattern typical of pulmonary carcinoma. Tumoral cells were immunopositive for Jaagsiekte sheep retrovirus-Env oncogenic protein. Based on these findings, the final diagnosis of ovine pulmonary adenocarcinoma was made.

Resumen El adenocarcinoma pulmonar ovino es una neoplasia pulmonar transmisible del ganado ovino causada por un beta retrovirus actualmente denominado retrovirus Jaagsiekte de las ovejas (JSRV). Las células Club (anteriormente llamadas células de Clara) de los bronquiolos y los neumocitos de tipo II de los alvéolos son las células oncogénicas que constituyen el objetivo de este virus. Se caracteriza clínicamente por tos intermitente, secreción nasal abundante y pérdida de peso progresiva, los tumores afectan aleatoriamente a todos los lóbulos pulmonares o tienen una distribución cráneo-ventral que simula una bronconeumonía. El diagnóstico definitivo del adenocarcinoma pulmonar ovino requiere que se identifique el retrovirus Jaagsiekte de las ovejas RVJO-Env, o bien, la presencia de proteínas específicas asociadas en las células neoplásicas, tales como la proteína oncogénica JSRV-Env. Un ovino Pelibuey macho de dos años con un historial de tos crónica y pérdida de peso progresiva fue tratado sin éxito con antibióticos y murió unos días más tarde. El examen post mortem reveló edema pulmonar y varias masas nodulares localmente extensas en los pulmones. A nivel microscópico, los tejidos tumorales estaban compuestos por grupos de células epiteliales neoplásicas que mostraban un patrón de crecimiento lepídico típico del carcinoma pulmonar. Las células tumorales fueron inmunopositivas para la proteína oncogénica Env del retrovirus Jaagsiekte de la oveja. Con base en estos hallazgos, se hizo el diagnóstico final de adenocarcinoma pulmonar ovino.

RESUMO O peso corporal (PC) do animal é uma característica econômica importante, que pode auxiliar na tomada de decisões no manejo dos animais. O objetivo do presente estudo foi desenvolver equações para a predição do PC em ovinos Pelibuey por meio da circunferência escrotal (CE). O PC (23,40±6,96kg) e a CE (20,25±6,19cm) foram registrados em 405 ovinos machos da raça Pelibuey no Centro de Integração Ovina da Região Sudeste do México. Os modelos lineares, logarítmicos, quadráticos, exponenciais, cúbicos e de regressão de potência foram utilizados para a análise dos dados. A correlação de Pearson (R), o coeficiente de determinação (R2), o coeficiente de determinação ajustado (Adj.R2), o erro do quadrado médio (EQM), o critério de informação de Akaike (AIC) e o critério de informação bayesiano (BIC) foram usados para selecionar o melhor modelo. O modelo de regressão de potência apresentou maiores R (0,93), R2 (0,86), Adj.R2 (0,86) e menores EQM (0,02), AIC (-989,44) e BIC (-981,44). O estudo atual sugere que a CE pode ser usada como um único preditor para o PC de ovinos Pelibuey em crescimento criadas em condições tropicais. (PC importante animais CE. . (CE) 23,40±6,96kg 2340696kg kg 23 40 6 96kg (23,40±6,96kg 20,25±6,19cm 2025619cm cm 20 25 19cm (20,25±6,19cm México lineares logarítmicos quadráticos exponenciais dados R, , (R) R2, (R2) Adj.R2, AdjR2 AdjR Adj (Adj.R2) EQM, (EQM) (AIC (BIC 0,93, 093 0,93 0 93 (0,93) 0,86, 086 0,86 86 Adj.R (0,86 0,02, 002 0,02 02 (0,02) 989,44 98944 989 44 (-989,44 981,44. 98144 981,44 981 (-981,44) tropicais (CE 2 4 (R (R2 (Adj.R2 (EQM 09 0,9 9 (0,93 08 0,8 8 (0,8 00 0,0 (0,02 989,4 9894 98 (-989,4 9814 981,4 (-981,44 (Adj.R 0, (0,9 (0, (0,0 989, (-989, 981, (-981,4 (0 (-989 (-981, ( (-98 (-981 (-9 (-

ABSTRACT The body weight (BW) of an animal is a vital economic trait that might help in decision-making in the handling of animals. The objective of the present study was to develop equations for the prediction of BW in Pelibuey sheep using scrotal circumference (SC). The BW (23.40 ± 6.96 kg) and SC (20.25 ± 6.19 cm) have been recorded in 405 male Pelibuey at the Southeastern Center for Ovine Integration, Mexico. Linear, logarithmic, quadratic, exponential, cubic, and power regression models were used for data analysis. Pearson correlation (R), Coefficient of determination (R2), Adjusted coefficient of determination (Adj.R2) Root mean square error (RMSE), Akaike information criterion (AIC), and Bayesian information criterion (BIC) were used to select the best model. Power regression model showed the highest R (0.93), R2 (0.86), Adj.R2 (0.86) and lowest RMSE (0.02), AIC (-989.44) and BIC (-981.44). The current study suggests that SC might be used as the only predictor for BW of growing Pelibuey sheep raised under tropical conditions. (BW decisionmaking decision making animals SC. . (SC) 23.40 2340 23 40 (23.4 696 6 96 6.9 kg 20.25 2025 20 25 (20.2 619 19 6.1 cm Integration Mexico Linear logarithmic quadratic exponential cubic analysis R, , (R) R2, (R2) AdjR2 AdjR Adj (Adj.R2 RMSE, (RMSE) AIC, (AIC) (BIC 0.93, 093 0.93 0 93 (0.93) 0.86, 086 0.86 86 Adj.R (0.86 0.02, 002 0.02 02 (0.02) 989.44 98944 989 44 (-989.44 981.44. 98144 981.44 981 (-981.44) conditions (SC 23.4 234 2 4 (23. 69 9 6. 20.2 202 (20. 61 1 (R (R2 (Adj.R (RMSE (AIC 09 0.9 (0.93 08 0.8 8 (0.8 00 0.0 (0.02 989.4 9894 98 (-989.4 9814 981.4 (-981.44 23. (23 20. (20 0. (0.9 (0. (0.0 989. (-989. 981. (-981.4 (2 (0 (-989 (-981. ( (-98 (-981 (-9 (-

Resumen El objetivo fue comparar los efectos de selenito de sodio (SS) y Sel-Plex® (SP) en el consumo de materia seca (CMS), ganancia diaria de peso (GDP), conversión alimenticia (CA), rendimiento de canales, Se en suero, músculos, albúmina, y globulinas en corderos Pelibuey. Cincuenta animales (PV=23.0 ± 1.1 kg; de 5 a 6 meses) se estratificaron y aleatoriamente asignaron a uno de cinco tratamientos (n=10): 1) Dieta basal, C); 2) C + 0.30 mg kg-1 MS de SS, 30SS; 3) C + 0.90 mg kg-1 MS de SS, 90SS; 4) C + 0.30 mg kg-1 MS de SP, 30SP; y 5) C + 0.90 mg kg-1 MS de SP, 90SP. No hubo efectos (P>0.05) en CMS; mientras que 90SP y 30SS mostraron GDP mayores (293 y 260 vs 245, 243, y 230 g día-1; P<0.05) en comparación con los demás tratamientos. La CA fue mejor para 90SP y C. Los PV finales, rendimientos de canales y la grasa dorsal no se afectaron (P>0.05). En Longissimus dorsi, 30SP incrementó (P<0.05) el Se con respecto a 90SP y C, y fue similar con 30SS y 90SS. No hubo efecto (P>0.05) en Gluteus maximus y Musculus deltoideus. La albúmina fue mayor con 30SP y 90SS; mientras que α-globulina fue mayor con 30SS y 90SP. En conclusión, 0.90 mg de SP mejoró la GDP y CA. Selenito y SP aumentaron el Se en suero hasta 0.30, y disminuyó con 0.90 mg por kilo de SP. En Longissimus dorsi, el Se se mejoró en 30SP con respecto 90SP y el C y no fue similar a 90SS y 30SS. El Se orgánico de 90SP mejoró el nivel de albúmina y α-globulinas.

Abstract The objective was to compare the effects of sodium selenite (SS) and Sel-Plex® (SP) on dry matter intake (DMI), daily weight gain (DWG), feed conversion (FC), carcass yield, Se in serum, muscle, albumin, and globulins in Pelibuey lambs. Fifty (50) animals (LW=23.0 ± 1.1 kg; 5 to 6 mo) were stratified and randomly assigned to one of five treatments (n=10): 1) Basal diet, C); 2) C + 0.30 mg kg-1 DM of SS, 30SS; 3) C + 0.90 mg kg-1 DM of SS, 90SS; 4) C + 0.30 mg kg-1 DM of SP, 30SP; and 5) C + 0.90 mg kg-1 DM of SP, 90SP. There was no effect (P>0.05) on DMI; while 90SP and 30SS showed higher DWGs (293 and 260 vs 245, 243, and 230 g d-1; P<0.05) compared to the other treatments. FC was better for 90SP and C. Final LWs, carcass yields and dorsal fat were not affected (P>0.05). In the Longissimus dorsi, 30SP increased (P<0.05) Se with respect to 90SP and C and was similar with 30SS and 90SS. There was no effect (P>0.05) on the Gluteus maximus and Musculus deltoideus. Albumin was higher with 30SP and 90SS; while α-globulin was higher with 30SS and 90SP. In conclusion, 0.90 mg of SP improved DWG and FC. Selenite and SP increased Se in serum up to 0.30, and it decreased with 0.90 mg per kilogram of SP. In the Longissimus dorsi, Se was improved in 30SP with respect to 90SP and C and was not similar to 90SS and 30SS. The organic Se of 90SP improved the level of albumin and α-globulins.

Abstract Background: Assessment of animal growth based on live weight (LW) in traditional sheep production systems is limited by the high cost of purchase and maintenance of livestock scales. Objective: To develop and evaluate equations for LW prediction using heart girth (HG) in growing Pelibuey sheep. Methods: A dataset (n=415) of clinically healthy male Pelibuey sheep from two months to one year of age, with an average LW of 25.96 ± 10.25 kg and HG of 68.31 ± 10.53 cm, were used. Three equations were evaluated: LW (kg) = −37.70 + 0.93 × HG (Eq. 1); LW (kg) = −1.74 + 0.19 × HG + 0.008 × HG2 (Eq. 2); and LW (kg) = 0.003 × HG2.68 (Eq. 3). Results: The correlation coefficient between LW and HG was r = 0.94 (p<0.001). The three equations showed a high concordance correlation coefficient (CCCs≥0.97). However, the random error was the main component of the mean square partition of the prediction error (≥82.78%) only for Eqs. 1 and 2. The test for parameter identity (intercept=0; slope=1) was accepted only for Eq. 2 (p>0.05). On the other hand, for Eqs. 1 and 3 the intercept was different from zero and the slope was different from one (p<0.05). Conclusion: The second-degree equation accurately and precisely estimated body weight of growing Pelibuey sheep using the HG as a sole predictor variable.

Resumen Antecedentes : Debido a las condiciones de los sistemas tradicionales de producción ovina, la evaluación del crecimiento animal en función del peso vivo (PV) está limitada por el alto costo de la báscula ganadera y su mantenimiento. Objetivo: Desarrollar y evaluar ecuaciones para predecir el peso corporal utilizando el perímetro torácico (PT) en ovinos Pelibuey en crecimiento. Métodos : Se utilizó un conjunto de datos (n=415) de ovinos Pelibuey machos clínicamente sanos, de dos meses a un año de edad y peso promedio de 25,96 ± 10,25 kg y PT de 68,31 ± 10,53 cm. Se evaluaron tres ecuaciones: PV (kg) = −37,70 + 0,93 × PT (Ec. 1), PV (kg) = −1,74 + 0,19 × PT + 0,008 × PT2 (Ec. 2) y PV (kg) = 0,003 × PT2,68 (Ec. 3). Resultados: El coeficiente de correlación entre PV y PT fue r=0,94 (p<0,001). Las tres ecuaciones mostraron alto coeficiente de correlación de concordancia (CCCs≥0,97). Sin embargo, el error aleatorio fue el componente principal de la partición cuadrática media del error de predicción (≥82,78%) solo para las Ecs. 1 y 2. Sin embargo, la prueba de identidad de parámetros (intersección = 0; pendiente = 1) solo se aceptó para la ecuación 2 (p>0,05). Por otro lado, el intercepto fue diferente de cero y la pendiente fue diferente de uno (p<0.05) para las Ecs. 1 y 3. Conclusión: La ecuación de segundo grado estima con exactitud y precisión el peso corporal de ovinos Pelibuey en crecimiento utilizando la PT como única variable predictora.

Resumo Antecedentes: Devido às condições dos sistemas tradicionais de produção de ovinos, a avaliação do crescimento animal com base no peso corporal (PV) é limitada pelo alto custo da balança pecuária, bem como pela manutenção sofisticada necessária. Objetivo: Desenvolver e avaliar equações para predizer o PV usando o perímetro torácico (PT) em ovinos Pelibuey em crescimento. Métodos: Um conjunto de dados (n=415) de ovinos Pelibuey machos clinicamente saudáveis de dois meses a um ano de idade, com peso médio de 25,96 ± 10,25 kg e PT de 68,31 ± 10,53 cm foi utilizado para o desenvolvimento das equações. Três equações foram avaliadas: PV (kg) = -37,70 + 0,93 × PT (Eq. 1), PV (kg) = -1,74 + 0,19 × PT + 0,008 × PT2 (Eq. 2) e PV (kg) = 0,003 × PT2,68 (Eq. 3). Resultados: O coeficiente de correlação entre PV e PT foi r = 0,94 (P < 0,001). As três equações apresentaram alto coeficiente de correlação e concordância (CCCs≥0,97). No entanto, o erro aleatório foi o principal componente da partição do quadrado médio do erro de predição (≥82,78%) apenas para as Eqs. 1 e 2. No entanto, o teste de identidade dos parâmetros (intercepto = 0; inclinação = 1) foi aceito apenas para a Eq. 2 (p>0,05). Por outro lado, para a Eq. 1 e 3, o intercepto foi diferente de zero e a inclinação foi diferente de um (p<0,05). Conclusões: A equação de segundo grau estima com precisão e acurácia o peso corporal de ovinos Pelibuey em crescimento usando o PT como única variável preditora.

ABSTRACT A study was conducted to evaluate the efficacy of ivermectin and albendazole sulfoxide for the control of gastrointestinal nematodes. Thirty Pelibuey ewes were randomly assigned to three experimental groups: Ivermectin 4% (10.2 mg/kg), albendazole sulfoxide 17% (3.75 mg/kg) and an untreated control group. Faecal samples were collected before drug administration (day 0) and on days 7, 14, 21, 28, 35, and 42 post-treatment. The quantitative diagnosis of the eggs was carried out using the McMaster technique and cultures were carried out to recover larvae by the migration method with the Baermann apparatus. The anthelmintic efficacy of the treatments was determined by the Abbott's formula and the effect of anthelmintics on the number of eggs per gram of faeces (EPG) by an analysis of variance with a completely randomized design. The most abundant species were Haemonchus contortus and Strongyloides papillosus. A significant decrease in the amount of EPG was observed from day 7 of treatment with both anthelmintics, with albendazole sulfoxide and ivermectin showing efficacy above 95% from day 7 and 14 post-treatment, respectively, until day 21. At 24 h post-treatment, ivermectin showed lower efficacy than albendazole sulfoxide (69.5 vs 90.9% respectively), but efficacy was similar and above 90% for both drugs from day 7. The efficacy of albendazole sulfoxide against Haemonchus contortus larvae was 88.2% at 24 h post-treatment compared to 69.5% for ivermectin, but only the latter showed an efficacy greater than 95% on days 14 and 21 post-administration. It is concluded that albendazole sulfoxide has a faster effect and a longer efficacy for the control of gastrointestinal nematode eggs, while ivermectin showed greater efficacy for the control of Haemonchus contortus larvae without evidence of resistance to both drugs.

RESUMEN Se realizó un estudio para evaluar la eficacia de la ivermectina y del albendazol sulfóxido para el control de nematodos gastrointestinales. Treinta ovejas Pelibuey fueron asignadas aleatoriamente a tres grupos experimentales: ivermectina al 4% (10.2 mg/kg), albendazol sulfóxido al 17% (3.75 mg/kg) y un grupo control no tratado. Se recolectaron muestras fecales antes de la administración de los fármacos (día 0) y en los días 7, 14, 21, 28, 35 y 42 pos-tratamiento. Se realizó el diagnóstico cuantitativo de los huevos mediante la técnica de McMaster y se realizaron cultivos para recuperar larvas por el método de migración con el aparato de Baermann. La eficacia antihelmíntica de los tratamientos se determinó por medio de la fórmula de Abbott y el efecto de los antihelmínticos sobre la cantidad de huevos por gramos de heces (HPGH) por medio de un análisis de varianza con un diseño completamente al azar. Las especies más abundantes fueron Haemonchus contortus y Strongyloides papillosus. Se observó una disminución significativa en la cantidad de HPGH a partir del día 7 del tratamiento con ambos fármacos, mostrando el albendazol sulfóxido y la ivermectina una eficacia por encima del 95% a partir del día 7 y 14 postratamiento, respectivamente, hasta el día 21. La eficacia del albendazol sulfóxido contra larvas de Haemonchus contortus fue de 88.2% a las 24 h pos-tratamiento en comparación con el 69.5% de la ivermectina, pero solo esta última mostró una eficacia superior al 95% los días 14 y 21 postadminstración. Se concluye que el albendazol sulfóxido tiene un efecto más rápido y una eficacia más prolongada para el control de huevos de nemátodos gastrointestinales, mientras que la ivermectina mostró una mayor eficacia para el control de larvas de Hamonchus contortus sin indicios de resistencia a ambos fármacos.

Resumo O objetivo deste trabalho foi avaliar o efeito da interação entre nível de alimentação (FL) e escore de condição corporal (BCS) sobre os parâmetros reprodutivos de ovelhas de pelo Pelibuey (Ovis aries). As unidades experimentais (64 ovelhas) foram distribuídas aleatoriamente a um dos quatro tratamentos: baixo nível de alimentação e baixo escore de condição corporal; alto nível de alimentação e baixo escore nas condições corporais; baixo nível de alimentação e alto escore nas condições corporais; e alto nível de alimentação e alto escore nas condições corporais. O efeito do escore de condição corporal de ovelhas foi significativo sobre as taxas de prenhez e parto. O efeito do nível de alimentação foi significativo sobre as taxas de ovulação, retorno do estro, prenhez e prolificidade. O efeito da interação entre escore de condição corporal e nível de alimentação foi significativo sobre as taxas de ovulação, retorno do estro, prenhez, parto e prolificidade. A função reprodutiva é mais sensível aos melhores efeitos nutricionais em ovelhas com baixo escore de condição corporal. FL (FL BCS (BCS Ovis aries. aries . aries) 64 (6 tratamentos corporais ovulação estro prolificidade 6 (

Abstract The objective of this work was to evaluate the effect of the interaction between feeding level (FL) and body condition score (BCS) on the reproductive parameters of Pelibuey hair sheep (Ovis aries). The experimental units (64 ewes) were randomly assigned to one of four treatments: low feeding level and low body condition score; high feeding level and low body condition score; low feeding level and high body condition score; and high feeding level and high body condition score. The effect of sheep body condition score was significant on the pregnancy and lambing rates. The effect of feeding level was significant on the ovulation, estrus returning, pregnancy, and prolificacy rates. The interaction effect between BCS and FL was significant on the ovulation, estrus returning, pregnancy, lambing, and prolificacy rates. The reproductive function is more sensitive to the better nutrition effects in sheep with a low body condition score. (FL (BCS Ovis aries. aries . aries) 64 (6 ewes treatments rates ovulation returning 6 (

Abstract Direct collection of biometric measurements (BM) from sheep is an expensive and stressful procedure for animals; instead, indirect and novel methods have recently been used. The objective of this study was to use digital image analysis (DIA) to predict biometric measurements of Pelibuey sheep as a non-invasive approach under on-farm conditions. Withers height (WH), body length (BL), body diagonal length (BDL), and rib depth (RD) were predicted in Pelibuey ewes using DIA. Images were taken from the left flank of 65 non-pregnant and nonlactating Pelibuey ewes using a digital camera and analyzed by DIA. The BM determined from both in vivo and by DIA presented positive and moderate (P < 0.05) correlation coefficients (r) of 0.43, 0.66, 0.73, and 0.75 for BL, BDL, WH, and RD, respectively. Regression equations from BM by DIA had determination coefficients (r2) of 0.19, 0.44, 0.54, and 0.56 for BL, BDL, WH, and RD, respectively. The equations developed were from low to moderate precision (r2 = 0.18 to 55), moderate to high accuracy with a bias correction factor (Cb > 0.69), and low to moderate reproducibility index (> 0.30). Overall, the use of DIA was able to predict the BM in Pelibuey ewes with low to moderate precision and accuracy. Factors affecting the accuracy and precision of this relationship should be further investigated.

Abstract The effect of breed on growth, characteristics, and carcass classification was investigated using 11 Charollais x Pelibuey (ChP) lambs, 10 Dorper x Pelibuey (DP) lambs, and 18 Pelibuey (P) lambs in an intensive production system in a warm-humid climate. A significant effect of genotype ( P<0.05) was observed on birth weight (BW), weaning weight (WW), and daily weight gain (DWG), all of which were higher in the ChP genotype. ChP and DP lambs reached commercial weight 35 and 23 d earlier, respectively than P lambs. Genotype has a marked influence on the carcass characteristics, affect conformation and classification of carcass. The probability of obtaining a carcass with good conformation and MEX 1 classification (good: MEX 1) is 72 % higher for the ChP genotype than for the P genotype. The loin and leg yields of the ChP genotype were higher than those of the other genotypes. The pH, temperature, and instrumental color of the carcass, meat, and subcutaneous fat were affected by genotype. ChP lambs showed better growth, characteristics, and carcass classification than lambs of the DP and P genotypes.

Resumen Se estudió el efecto de la raza en el crecimiento, las características y la clasificación de la canal utilizando 11 corderos Charollais x Pelibuey (ChP), 10 corderos Dorper x Pelibuey (DP) y 18 corderos Pelibuey (P) bajo un sistema de producción intensiva en un clima cálido-húmedo. Se observó un efecto significativo del genotipo (P<0.05) en el peso al nacer (PN), el peso al destete (PD) y la ganancia diaria de peso (GDP), todos ellos fueron mayores en el genotipo ChP. Los corderos ChP y DP alcanzaron el peso comercial 35 y 23 días antes, respectivamente, que los corderos P. El genotipo tiene una marcada influencia en las características de la canal, afecta la conformación y la clasificación de la canal. La probabilidad de obtener una canal con buena conformación y clasificación MEX 1 (buena: MEX 1) es 72 % mayor para el genotipo ChP que para el genotipo P. Los rendimientos de lomo y pierna del genotipo ChP fueron mayores que los de los otros genotipos. El pH, la temperatura y el color instrumental de la canal, la carne y la grasa subcutánea fueron afectados por el genotipo. Los corderos ChP mostraron un mejor crecimiento, características y clasificación de la canal que los corderos de los genotipos DP y P.

Abstract The objective of this study is to evaluate the effect of β-agonists (BA), Zilpaterol Hydrochloride (ZH), and Ractopamine Hydrochloride (RH) on the biometric parameters and the muscle fiber thickness in Pelibuey lambs (n = 6). The control group was fed a standard diet (16% protein content and 12 MJ per day); treatment groups received a standard diet supplemented with ZH or RH for 37 days and was assessed presence of BA in samples of muscle tissues, and urine. The effect of Daily Weight Gain (DWG) and Food Conversion Rate (FCR) on muscle fiber thickness was determined by Scanning Electron Microscopy (SEM) and Digital Image Analysis (DIA). Results showed an increase of 30% in DWG in the ZH group, compared with RH. While FCR was lower in ZH (3.83) than in RH (4.85). In both BA treatments, the withdrawal time was sufficient to minimize drug concentration in meat. In contrast with the control group, muscle fiber thickness increased in BA treated groups (ZH = 69.2%, and RH = 15.6%). In conclusion, ZH displayed a higher carcass yield in Pelibuey lambs.

Resumen El objetivo de este estudio fue evaluar el efecto de los β-agonistas (BA), Clorhidrato de Zilpaterol (ZH) y el Clorhidrato de Ractopamina (RH) sobre los parámetros biométricos y el grosor de la fibra muscular en corderos Pelibuey (n = 6). El grupo control recibió una dieta estándar (DS) (16% de contenido de proteína y 12 MJ por día), mientras que los grupos de tratamiento recibieron DS+ZH o DS+RH durante 37 días. Se evaluó la presencia de BA en tejido muscular y orina, determinó el aumento de peso diario (DWG), la tasa de conversión de alimentos (FCR) sobre el grosor de la fibra muscular, mediante microscopía electrónica de barrido (SEM) y análisis de imagen digital (DIA). Los resultados mostraron 30% más en DWG en el grupo ZH, que en RH. Mientras que la FCR fue menor en ZH (3.83) que en RH (4.85). El tiempo de supresión aplicado fue suficiente para que los grupos ZH y RH no mostraran residuos. En contraste con el grupo de control, el grosor de las fibras musculares aumentó en los grupos tratados con BA (ZH = 69.2% y RH = 15.6%).

Resumen El efecto del genotipo (Pelibuey vs Katahdin), tipo de parto (simple vs dobles) y sexo (machos vs. hembras) sobre las características de la canal y de sus cortes, además del perfil de ácidos grasos del lomo fueron evaluados en 66 corderos sacrificados al destete. El rendimiento de la canal y del costillar fue mayor (P<0.05) en la raza Pelibuey. El peso al sacrificio, peso de canal y rendimiento del costillar fue mayor (P<0.01) en crías de parto simple, mientras que el rendimiento de paleta y pierna fue menor (P< 0.01) que en crías de parto doble. La proporción del tejido blando de los diferentes cortes fue mayor (P<0.05), pero el de hueso fue menor (P< 0.05) en crías de parto simple que las de parto doble. Las hembras tuvieron mayor (P<0.05) proporción de tejido blando y menor proporción de hueso (P<0.01) que los machos. Las concentraciones de C18:1n7 y C20:4n-6 fueron mayores (P< 0.05) en la raza Pelibuey que, en la Katahdin, mientras que los C22:5n-3 y C22:6n-3 fueron menores. El porcentaje de ácidos grasos monoinsaturados fue mayor (P<0.05) en la carne de crías de partos simples, en tanto que el de los ácidos grasos poliinsaturados totales y n-3 fue mayor (P<0.05) en crías de partos dobles. Las características de la canal, la composición tisular de los cortes comerciales y el perfil de ácidos grasos en ovinos de pelo sacrificados al destete mostraron más cambios por el tipo de parto que por el genotipo o el sexo.

Abstract The effect of the genotype (Pelibuey vs Katahdin), type of lambing (single vs. double) and sex (males vs. females) on the characteristics of the carcass and its cuts, in addition to the fatty acid profile of the loin were evaluated in 66 lambs slaughtered at weaning. The yield of the carcass and ribs were higher (P<0.05) in the Pelibuey breed. Slaughter weight, carcass weight and rib yield were higher (P<0.01) in single-born lambs, while the yield of shoulder and leg were lower (P<0.01) than in double-born lambs. The proportion of soft tissue of the different cuts was higher (P<0.05), but that of bone was lower (P< 0.05) in single-born lambs than in double-born lambs. Females had a higher (P<0.05) proportion of soft tissue and a lower proportion of bone (P<0.01) than males. The concentrations of C18:1n7 and C20:4n-6 were higher (P<0.05) in the Pelibuey breed than in the Katahdin breed, while the C22:5n-3 and C22:6n-3 were lower. The percentage of monounsaturated fatty acids was higher (P<0.05) in the meat of single-born lambs, while that of total polyunsaturated fatty acids and n-3 was higher (P<0.05) in double-born lambs. The characteristics of the carcass, the tissue composition of the commercial cuts and the fatty acid profile in hair sheep slaughtered at weaning varied more due to the type of lambing than due to the genotype or sex.