SUMMARY: The cattle in the Pantanal region show a notable influence from Bos indicus breeds and their crossbreeds. However, a comprehensive biometric assessment of the reproductive system in these animals is currently lacking. This study evaluated the effects of breed, age, carcass weight, and estrous cycle phase on female reproductive system morphometry. A total of 124 healthy, non-pregnant reproductive tracts (83 Nelore and 41 Crossbred) were collected at a slaughterhouse. Neither the volume and weight of the ovaries nor the majority of uterine dimensions were affected by breed. Compared to heifers, cows showed longer uterine horns, a larger external caudal diameter of the uterine horns and body, and a greater external cranial diameter and internal caudal diameter of the cervix. The carcass weight (below vs. within commercial weight) affected the length of the uterine horns, uterine body, and cervix. Ovaries with a corpus luteum presented higher volume and weight than those with only follicles. Although the uterine measurements in the luteal phase were increased, the cycle stage did not affect the uterine morphometry. The average number of cervical rings was 5.0, independent of weight or breed. Crossbred animals presented a higher first cervical ring. Age didn´t influence the number, height, or distance between cervical rings. Deviation from the normal alignment of the cervix was recorded in 14.29 % of the animals, with a higher occurrence among Nelore cattle; deviation from the median axis was the most common (30%). This study emphasizes various parameters influencing the morphometry of the female reproductive system in Nelore cattle and their crosses, which could be crucial for implementing reproductive biotechnology techniques better suited to the morphological characteristics of zebu breeds.

RESUMEN: El ganado de la región del Pantanal muestra una notable influencia de las razas Bos indicus y sus cruces. Sin embargo, actualmente falta una evaluación biométrica exhaustiva del sistema reproductivo de estos animales. Este estudio evaluó los efectos de la raza, la edad, el peso de la canal y la fase del ciclo estral sobre la morfometría del sistema reproductivo de la hembra. En un matadero se recogieron un total de 124 tractos reproductivos sanos y no preñados (83 Nelore y 41 cruzados). Ni el volumen ni el peso de los ovarios ni la mayoría de las dimensiones del útero se vieron afectados por la raza. En comparación con las novillas, las vacas mostraron cuernos uterinos más largos, un diámetro caudal externo más grande de los cuernos y del cuerpo uterino, y un diámetro craneal externo y un diámetro caudal interno más grandes del cuello uterino. El peso de la canal (por debajo versus dentro del peso comercial) afectó la longitud de los cuernos uterinos, el cuerpo uterino y el cuello uterino. Los ovarios con cuerpo lúteo presentaron mayor volumen y peso que aquellos con solo folículos. Aunque las medidas uterinas en la fase lútea aumentaron, la etapa del ciclo no afectó la morfometría uterina. El número promedio de anillos cervicales fue de 5,0, independientemente del peso o la raza. Los animales mestizos presentaron un primer anillo cervical más alto. La edad no influyó en el número, altura o distancia entre anillos cervicales. La desviación de la alineación normal del cuello uterino se registró en el 14,29 % de los animales, con mayor ocurrencia en el ganado Nelore; la desviación del eje de la mediana fue la más común (30%). Este estudio enfatiza varios parámetros que influyen en la morfometría del sistema reproductor de las hembras en el ganado Nelore y sus cruces, lo que podría ser crucial para implementar técnicas de biotecnología reproductiva más adecuadas a las características morfológicas de las razas cebú.

Resumen La recría de vaquillonas de reposición en sistemas de cría es un factor importante que afecta directamente la productividad de las empresas ganaderas. El objetivo de este estudio fue evaluar el desempeño reproductivo de vaquillonas en el primer servicio, considerando variables morfoestructurales y de desarrollo reproductivo. Se utilizaron 142 hembras de 22 a 24 meses de edad cruza cebú, previamente seleccionadas por peso (se consideró un mínimo de 67% del peso estimado para una vaca adulta bajo el sistema). Se utilizó un diseño observacional antes del servicio en el que se dividieron en 3 grupos según, grado de desarrollo reproductivo (GDR 1 a 3), peso vivo (PV), condición corporal (CC 1-9) y mediciones zoométricas. El servicio fue realizado mediante inseminación artificial a tiempo fijo (IATF) y servicio natural. El diagnóstico de gestación se llevó a cabo a los 32 días luego de la IATF y 35 días después de retirados los toros para el servicio natural. Los resultados demostraron diferencias significativas entre las variables de crecimiento y desarrollo, excepto en perímetro de la caña y alzada a la grupa. Para PV las GDR1 fueron 10% más pesadas que las GDR3. La prueba de χ2 encontró asociación entre servicio natural y GDR con 50, 82 y 32%, como así también en la preñez general de 84, 92 y 67% de preñez en GDR 1, 2 y 3, respectivamente. En conclusión, para la selección pre-servicio en vaquillonas de reposición, es importante considerar no solo el peso vivo, sino también el grado de desarrollo reproductivo y las variables zoométricas.

Abstract The breeding of replacement heifers in breeding systems is an important factor that directly affects the productivity of livestock companies. The aim of this study was to assess the reproductive performance of replacement heifers during their first breeding season, considering morphostructural and reproductive development variables. 142 zebu cross females of 22 to 24 months of age were used, previously selected by weight (a minimum of 67% of the estimated weight for an adult cow under the system was considered). An observational design was used before service in which they were divided into 3 groups according to the degree of reproductive development (RTS 1 to 3), live weight (LW), body condition (BCS 1-9), and zoometric measurements. The service was carried out by artificial insemination at a fixed time (TAI) and natural service (NS). The pregnancy diagnosis was carried out 32 days after the TAI and 35 days after the bulls were removed for NS. The results showed significant differences between the growth and development variables, except in cannon bone circumference and rump height. For LW the RTS1 were 10% heavier than the RTS3. The χ2 test identified association between NS and RTS with 50, 82 and 32%, as well as in general pregnancy of 84, 92 and 67% pregnancy in RTS1, 2 and 3, respectively. In conclusion, for the pre- breeding selection of replacement heifers, it is essential to consider not only live weight but also the degree of reproductive development and zoometric variables.

This study aimed to evaluate the effect of licuri (Syagrus coronate) cake (LC) on the chemical composition, cholesterol content, and fatty acid profile of meat from cull cows finished in a high-grain feedlot. We used 40 Zebu cull cows of 108 months of age and with an initial weight of 318 ± 38.17 kg. The animals were distributed into four treatments in a completely randomized design: control (0 g/kg LC), 50, 100, and 150 g/kg LC in the total dry matter of the total diet, and were confined for 105 d. The inclusion of LC influenced the content of total lipids and total cholesterol of the beef. The inclusion of LC influenced the concentrations of fatty acids (C12:0, C14:0, C14:1, C16:0, and C17:1) in the meat of cull cows. There was an effect of the inclusion of LC on the fatty acids C18:2n6t, C18:2n6, and C18:3n3 of the meat of cull cows finished in the feedlot. The inclusion of up to 50 g/kg LC in the diet of cows provided lower values for the sum (Σ) of saturated fatty acids and higher values for Σ monounsaturated fatty acids in the meat. The Σ polyunsaturated fatty acids decreased with the inclusion of LC in the diet. We recommend using up to 50 g/kg of licuri cake inclusion in the diet of cull cows finished in the feedlot.

Resumo O objetivo do presente estudo foi avaliar as características da carcaça e da carne de novilhos confinados no Brasil de acordo com o grupo genético por meio de uma revisão sistemática e meta-análise. Foi realizada busca eletrônica de artigos nas bases de dados Scielo e Google Acadêmico e os dados foram agrupados de acordo com a predominância genética. Os resultados foram testados quanto à heterogeneidade e submetidos ao teste de normalidade e teste F e as médias comparadas pelo teste de Tukey. Novilhos predominantemente britânicos foram terminados em idade mais jovem, necessitaram de tempos de confinamento mais longos e apresentaram menores pesos de carcaça quente e menores áreas de olho de lombo no abate. Os percentuais de carcaça muscular foram maiores nos novilhos Continentais e Sintéticos em relação aos Britânicos e Zebu, enquanto os percentuais de gordura foram maiores nos Britânicos e Zebu em comparação aos continentais e sintéticos. O marmoreio da carne foi maior nos novilhos britânicos, continentais e mestiços em relação aos novilhos sintéticos e zebuínos. A origem do novilho britânico permite menor idade de abate, embora leve à redução do peso da carcaça quente, enquanto a predominância genética do zebu pode produzir carcaças com alto percentual de gordura. metaanálise. metaanálise meta análise. análise meta-análise Tukey jovem abate zebuínos

Abstract The aim of the present study was to assess the carcass and meat characteristics of feedlot steers in Brazil according to genetic group through a systematic review and meta-analysis. An electronic article search was conducted at the Scielo and Google Scholar databases and data were grouped according to genetic predominance. The results were tested for heterogeneity and submitted to a normality test and F test and the means were compared by the Tukey test. Predominantly British steers were finished at a younger age, required longer confinement times and displayed lower hot carcass weights and smaller loin eye areas at slaughter. Muscle carcass percentages were higher in Continental and Synthetic steers compared to British and Zebu steers, while fat percentages were higher in British and Zebu steers compared to continental and synthetic breeds. Meat marbling was higher in British, continental and crossbreed steers compared to synthetic and zebu steers. A British steer origin allows for decreased slaughter age, although leading to reduced hot carcass weight, while a genetic Zebu predominance can produce high fat percentage carcasses. metaanalysis. metaanalysis meta analysis. analysis meta-analysis age breeds weight carcasses

Abstract Growth and carcass traits are essential selection criteria for beef cattle breeding programs. However, it is necessary to combine these measurements with body composition traits to meet the demand of the consumer market. This study aimed to estimate the genetic parameters for visual scores, growth (pre and post-weaning weights), and carcass (rib eye area (REA), back and rump fat thickness) traits in Nellore cattle using Bayesian inference. Data from 12,060 animals belonging to the HoRa Hofig Ramos herd were used. Morphological traits were evaluated by the MERCOS methodology. The heritability estimates obtained ranged from low to high magnitude, from 0.15 to 0.28 for visual scores, 0.13 to 0.44 for growth, and from 0.42 to 0.46 for carcass traits. Genetic correlations between visual scores and growth traits were generally of moderate to high magnitudes, however, visual scores showed low correlations with carcass traits, except between sacral bone and structure and REA. Selection for visual score traits can lead to favorable responses in body weight and vice versa, but the same is not true for carcass traits. Morphological categorical traits can be used as complementary tools that add value to selection. programs However market pre postweaning post weaning weights, weights , weights) rib REA, REA (REA) thickness inference 12060 12 060 12,06 methodology magnitude 015 0 15 0.1 028 28 0.2 013 13 044 44 0.4 042 42 046 46 magnitudes however versa (REA 1206 1 06 12,0 01 0. 02 2 04 4 120 12,

Resumen Los pastos dedicados a la producción ganadera en Venezuela tienen una baja concentración de proteína cruda. Una de las estrategias nutricionales para corregir el déficit de proteína del forraje es el uso de nitrógeno no proteico en la dieta. Con el objetivo de evaluar el efecto de dos fuentes nitrógeno no proteico sobre el perfil metabólico de vacas lecheras lactantes, 31 vacas F1 Holstein × Cebú multíparas con promedios de 419 ± 46 kg de peso vivo y 17,1 ± 3,3 kg leche/animal·d-1 se asignaron de forma aleatoria a dos tratamientos durante 91 días: 1) 59 g·animal·d-1de urea y 2) 64 g·animal·d-1de Optigen II® como fuente de urea de degradación lenta (UDL). Los animales pastaron (2,12 AU·ha-1) en Urochloa decumbens,U. humidicola y U. brizantha (7,98-9,61 % PC); adicionalmente, se les suministraba 4 kg·animal·d-1 de alimento concentrado (15 % PC) y 108, 60 y 108 g·animal·d-1 de mineral, melaza y grasa sobrepasante, respectivamente. Cada 28 días se determinó en suero sanguíneo las concentraciones de glucosa, proteínas totales, albúmina, colesterol, urea, β-hidroxibutirato, y la actividad de las enzimas aspartato aminotransferasa y gamma-glutamil transferasa. Los datos se analizaron mediante ANAVAR bajo un diseño completamente al azar con medidas repetidas. No hubo diferencias entre los tratamientos en las variables estudiadas; sin embargo, el tiempo de muestreo influyó en todas ellas. No se observaron interacciones tratamiento × tiempo, excepto para la concentración de albúmina, que fue mayor en urea en el día 0. Los resultados obtenidos indican que bajos las condiciones experimentales del presente trabajo, Optigen II® no ofrece ventajas adicionales sobre la urea con respecto a los indicadores sanguíneos del metabolismo energético y proteico y de la funcionalidad hepática en vacas lecheras.

Abstract Pastures dedicated to cattle production in Venezuela have a low crude protein concentration. One of the nutritional strategies to correct the forage protein deficit is using non-protein nitrogen in the diet. To evaluate the effect of two non-protein nitrogen sources on the metabolic profile of lactating dairy cows, 31 F1 Holstein × Zebu multiparous cows averaging 419 ± 46 kg body weight and 17.1 ± 3.3 kg milk·animal·d-1 were randomly assigned to two treatments for 91 days: 1) 59 g·animal-1·d-1 of urea and 2) 64 g·animal-1·d-1 of Optigen II® as slow-release urea (SRU). The animals were grazing (2.12 AU·ha-1) on Urochloa decumbens, U. humidicola, and U. brizantha(7.98-9.61 % CP) and supplied with 4 kg·animal·d-1 of concentrate (15 % CP), and 108, 60, and 108 g·animal·d-1 of mineral, molasses, and bypass fat, respectively. Glucose, total protein, albumin, cholesterol, urea, and β-hydroxybutyrate concentrations, aspartate aminotransferase, and gamma-glutamyl transferase activities were determined in blood serum samples every 28 days. ANOVA analyzed data in a completely randomized design with repeated measures. There were no differences among treatments in the parameters investigated; however, collecting time influenced all of them. No treatment × time interactions were found except for albumin concentration, higher in urea at day 0. The results indicate that under the conditions assayed in the present work, Optigen II® offers no advantage over urea concerning blood indicators of energy and protein metabolism and hepatic functionality in dairy cows.

RESUMEN La fimosis suele desarrollarse secundaria a un caso de acropostitis. Generalmente se inicia como una inflamación aguda de la mucosa prepucial que se acompaña por edema, afectación de la submucosa y daño al tejido conectivo, el cual, para recuperarse sintetiza colágeno y genera tejido fibroso, que provoca estrechez de la luz prepucial e impide la salida del pene. Se presenta una alternativa técnica quirúrgica para tratar casos de fimosis en toros cebú con daño o pérdida de gran cantidad de mucosa prepucial, en los cuales las técnicas de tratamiento tradicionales ya no son exitosas.

ABSTRACT Phimosis usually develops secondary to a case of acroposthitis. It generally begins as an acute inflammation of the preputial mucosa that is accompanied by oedema, involvement of the submucosa, and damage to the connective tissue, which, to recover, synthesizes collagen and generates fibrous tissue, which causes narrowing of the preputial lumen and prevents the exit of the penis. An alternative surgical technique is presented to treat cases of phimosis in zebu bulls with damage or loss of a large amount of preputial mucosa, in which traditional treatment techniques are no longer successful.

ABSTRACT The increase in environmental temperature is affecting the thermal environment to which cattle are exposed, decreasing productive and reproductive performance. Heat shock proteins (HSP) have been used as the main indicator of bovine adaptability to heat stress conditions. The expression of hsp60, hsp70, and hsp90 genes was analyzed in 33 crossbred female cattle (Holstein x Zebu and Brown Swiss x Zebu), lactating, and non-lactating. Animals were sampled two times per day in the state of Veracruz, and expression was estimated by using real-time PCR with fluorescently labeled probes. Statistical analysis of gene expression was carried out by a repeated measures model using PROC MIXED of SAS. The expression of hsp60 and hsp70 genes at midday was different (p < 0,001 and p = 0,01, respectively) from that manifested during the early morning. The results of hsp gene expression may help in developing future crossbreeding programs by recognizing animals that can maintain higher homeostasis under heat stress conditions.

RESUMEN El aumento de la temperatura ambiental está afectando el ambiente térmico al que está expuesto el ganado, disminuyendo su desempeño productivo y reproductivo. Las proteínas de choque térmico (HSP) han sido utilizadas como el principal indicador de adaptabilidad de los bovinos a las condiciones de estrés calórico. Se analizó la expresión de los genes hsp60, hsp70 y hsp90 en 33 hembras mestizas bovinas (Holstein x Cebú y Suizo Pardo x Cebú), lactantes y horras. Los animales fueron muestreados dos veces por día en el estado de Veracruz y la expresión de los genes fue realizada mediante PCR de tiempo real con sondas marcadas con fluorescencia. El análisis estadístico de la expresión de los genes se llevó a cabo mediante un modelo de medidas repetidas, utilizando PROC MIXED de SAS. La expresión de los genes hsp60 y hsp70 al medio día fue diferente (p < 0,001 y p = 0,01, respectivamente) a la manifestada durante la madrugada. Los resultados de la expresión de los genes hsp pueden ayudar a desarrollar futuros programas de cruzamiento al reconocer animales que puedan mantener una mayor homeostasis bajo condiciones de estrés calórico.

RESUMEN En el presente trabajo se reporta el primer caso de un bovino de raza Brahman de 5 años, el cual se remitió por presentar una masa en el tercer parpado en el ojo izquierdo que obstruía la visión. El análisis histopatológico de la muestra remitida evidencia un carcinoma de células escamosas bien diferenciado sin evidencia de invasión linfovascular. El manejo terapéutico consistió en exenteración para evitar recidivas, por lo cual la evolución del paciente fue satisfactoria sin causar problemas en su rendimiento productivo. Se ha descrito que un posible factor de riesgo está relacionado con una permanente exposición a la luz solar que afecta la replicación del ADN de las células e induce procesos tumorales. Esto es cierto en los sistemas de cría de ganado, donde las hembras permanecen la mayor parte del tiempo en pastoreo y expuestas a la radiación ultravioleta, lo que explicaría la razón de la presentación de esta neoplasia en este tipo de pacientes. En ese sentido, es indispensable prestar atención y realizar monitoreo a las anormalidades que se puedan presentar en el ganado ya sea cebuino o taurino.

ABSTRACT In this paper a 5-year-old Brahman breed bovine is reported, which was submitted by presenting a mass in the third eyelid of the left eye which obstructed vision. Histopathological analysis of the submitted sample shows a well-differentiated squamous cell carcinoma with no evidence of lymphovascular invasion. The therapeutic management consisted of exenteration to avoid recurrences, for which the patient's evolution was satisfactory without causing problems in his productive performance. It has been described that a possible risk factor is related to permanent exposure to sunlight that affects the replication of DNA in cells and induces tumor processes. While it is true; in cattle breeding systems where females spend most of the time grazing and are exposed to ultraviolet radiation, this would explain the reason for the presentation of this neoplasm in this type of patient. In this sense, it is essential to pay attention and monitor abnormalities that may occur in cattle, whether Zebu or Taurine.

RESUMEN El estudio tuvo como objetivo estimar la seroprevalencia y factores de riesgo para Mycobacterium avium subsp. paratuberculosis en Villavicencio, Colombia. Se tomaron muestras de sangre a 1000 bovinos de doble propósito en 24 fincas. El diagnóstico se realizó mediante ELISA indirecta para la detección de anticuerpos. Los factores de riesgo fueron determinados mediante pruebas univariadas y multivariadas. La seroprevalencia general de Mycobacterium avium subsp. paratuberculosis fue 52.4% y la del hato de 100%. Se identificaron como factores de riesgo el sexo hembra, animales mayores de 4 años, y venta de animales. La raza cebú fue considerado como factor de protección.

ABSTRACT The study aimed to estimate the seroprevalence and risk factors for Mycobacterium avium subsp. paratuberculosis in Villavicencio, Colombia. Blood samples were taken from 1000 dual-purpose cattle in 24 farms. The diagnosis was done by indirect ELISA for the detection of antibodies. Risk factors were determined using univariate and multivariate tests. The overall seroprevalence of Mycobacterium avium subsp. paratuberculosis was 52.4% and that of the herd was 100%. Female sex, animals older than 4 years, and sale of animals were identified as risk factors. The zebu breed was considered as a protection factor.

Abstract Introduction. Studies on the structural characteristics of the ovary associated with the quality of the cumulus-oocyte complex (COCs) in cattle contribute to the definition of strategies to improve reproductive efficiency. Objective. To determine the weight and size of the ovaries, follicle quality, and COCs in Zebu females, in order to establish differences between the right and left ovary. Materials and methods. Between March and July 2017, 52 ovaries were obtained from twenty-six Zebu cows. The ovaries and follicles were weighed and measured. The follicles were grouped into three categories: a) <3 mm (TFI), b) 3-6 mm (TFII) and c) >6 mm (TFIII). The follicles quality was determined by the irrigation-translucency technique (TIT) and the COCs by the characteristics of the cytoplasm and cumulus cells as good (CI), fair (CII), and poor (CIII), and by cresyl brilliant blue test were categorized as BCB+ and BCB-. Results. Ovarian length, width and weight were 2.7 ± 0.6 cm, 1.8 ± 0.5 cm, and 7.0 ± 3 g, respectively, with differences for length and weight between the right and left ovary (p<0.01). The highest number of follicles were obtained in TFI (p<0.05). The 88.56 % of the follicles evaluated were of good quality. A total of 52 % and 44.2 % of COCs were classified as CI and BCB+, respectively. When follicle size and COC quality were considered, it was shown that in the TFI group 22 % were IC, 34 % CII, and 44 % CIII, and in the TFII group 31 % were IC, 21 % CII and 48 % CIII. No differences were observed between left and right ovary. Conclusion. The right ovary presented a greater size and weight, a greater number of follicular structures and a greater number of good quality CCOs.

Resumen Introducción. Estudios sobre características estructurales del ovario asociadas con calidad del complejo cúmulos-oocito (COCs) en bovinos, contribuyen con la definición de estrategias para mejorar la eficiencia reproductiva. Objetivo. Determinar el peso y tamaño de los ovarios, calidad de los folículos y COCs en hembras Cebú, para establecer diferencias entre el ovario derecho e izquierdo. Materiales y métodos. Entre marzo y julio del 2017, se obtuvieron 52 ovarios de veintiséis vacas Cebú. Los ovarios y folículos se pesaron y midieron. Los folículos se agruparon en tres categorías: a) <3 mm (TFI), b) 3-6 mm (TFII) y c) >6 mm (TFIII). La calidad de los folículos se determinó mediante la técnica de irrigación-traslucidez (TIT) y la de COCs por las características del citoplasma y células del cúmulo como buena (CI), regular (CII) y mala (CIII), y mediante la prueba azul brillante de cresilo se categorizaron como BCB+ y BCB-. Resultados. La longitud, ancho y peso de los ovarios fueron 2,7 ± 0,6 cm, 1,8 ± 0,5 cm y 7,0 ± 3 g, respectivamente, con diferencias para longitud y peso entre ovario derecho e izquierdo (p<0,01). La mayor cantidad de folículos se obtuvieron en TFI (p<0,05). El 88,56 % de los folículos evaluados fueron de buena calidad. El 52 % y 44,2 % de COCs fueron clasificados como CI y BCB+, respectivamente. Cuando se consideró el tamaño del folículo y la calidad del COCs, se evidenció que en el grupo TFI el 22 % fueron CI, el 34 % CII y el 44 % CIII, y el TFII el 31 % fue CI, el 21 % CII y el 48 % CIII. No se observan diferencias entre ovario izquierdo y derecho. Conclusión. El ovario derecho presentó un mayor tamaño y peso, mayor número de estructuras foliculares y mayor número de CCOs de buena calidad.

RESUMEN El objetivo del estudio fue evaluar la influencia de la edad de toretes al pastoreo sobre su comportamiento diurno en praderas de Setaria sphacelata. Las variables forrajeras fueron la disponibilidad y valor nutritivo de la dieta, y las variables animales fueron el peso vivo, tamaño y frecuencia de bocados, y comportamiento diurno. De un lote de 36 toretes se seleccionaron cuatro toretes cruzados Brown Swiss x cebú con un peso vivo inicial de 285.8 ± 18.1 kg que pastoreaban en un área de 29 ha (11 potreros). Las evaluaciones se hicieron cuando los animales alcanzaron las edades de 12 (T1), 15 (T2) y 18 (T3) meses. Se utilizó un diseño en bloque completo al azar. La disponibilidad forrajera presentó diferencias (p<0.05) entre tratamientos; no obstante, la asignación forrajera y la calidad nutritiva de la dieta no comprometió su comportamiento. El peso de los bocados fue mayor en T3 (0.87 ± 0.22 g por bocado; p<0.05), pero sin diferencias en la frecuencia de bocados. La actividad de pastoreo fue similar para T1 (5.09 ± 0.95 h) y T2 (5.38 ± 0.44 h), pero inferior (p<0.05) para T3 (4.05 ± 0.22 h). Los toretes de menor edad (T1) dedicaron menos tiempo a la rumia, y mayor tiempo al pastoreo y otras actividades. La mayor frecuencia de pastoreo se presentó al finalizar el tiempo diurno (16:00 a 18:00 h). Se concluye que la edad de los toretes influye en su comportamiento diurno, haciendo que toretes de mayor edad dediquen menos tiempo al pastoreo e incrementen el tamaño de bocados y el tiempo de rumia.

ABSTRACT The aim of this study was to evaluate the influence of the age of bulls at grazing on their diurnal behaviour in Setaria sphacelata meadows. The forage variables were the availability and nutritive value of the diet, and the animal variables were body weight, size and frequency of bites, and diurnal behaviour. Four Brown Swiss x zebu crossed bulls with an initial live weight of 285.8 ± 18.1 kg that grazed in an area of 29 ha (11 paddocks) were selected from a group of 36 bulls. The evaluations were done when the animals reached the ages of 12 (T1), 15 (T2) and 18 (T3) months. A randomized complete block design was used. Forage availability showed differences (p<0.05) between treatments; however, the forage allocation and the nutritional quality of the diet did not compromise their performance. Bite weight was higher in T3 (0.87 ± 0.22 g per bite; p<0.05), but without differences in bite frequency. Grazing activity was similar for T1 (5.09 ± 0.95 h) and T2 (5.38 ± 0.44 h), but lower (p<0.05) for T3 (4.05 ± 0.22 h).Younger bulls (T1) spent less time ruminating, and more time in grazing and other activities. The highest frequency of grazing occurred at the end of the daytime (16:00 to 18:00 h). It is concluded that the age of bull influences their diurnal behaviour, causing older bulls spent less time in grazing and increase the size of bites and rumination time.

Resumen El toro es un factor de importancia genética y económica en un hato ganadero, ya que de este dependerán las próximas generaciones; por lo tanto, es esencial la evaluación de la calidad seminal y la criopreservación de su material genético. El objetivo del estudio fue evaluar el efecto de dos temperaturas de dilución sobre la calidad de semen de ganado cebuino del Trópico Peruano. Dos toros Gyr fueron colectados semanalmente mediante electroeyaculación. Las muestras se colocaron en baño maría a 34°C y se analizaron las características macroscópicas y microscópicas del semen. Solo los eyaculados con >60% de motilidad y <20% de anormalidades fueron procesados, separándolos en dos tratamientos. El T1 consistió en predilución 1:1 a 34°C, luego de 30 minutos una dilución final agregando el dilutor a 34°C. El T2 consistió en predilución 1:1 a 34°C y a los 30 minutos de estabilización se llevó a refrigeración conjuntamente con el dilutor, para luego realizar la dilución final a 5°C. La calidad seminal fue analizada luego de 16 horas de refrigeración. El porcentaje de vitalidad en T1 (80,89%) fue mayor que en T2 (71,22%) (p<0,05), la reacción positiva a la prueba hipoosmótica fue mayor en T1 (71,11%) que en T2 (60%) (p<0,05). La integridad acrosomal y los rasgos morfométricos no variaron según tratamientos. En conclusión, la dilución inicial y final a 34°C en toros Gyr influye positivamente sobre la calidad seminal antes de la congelación de pajillas de semen.

Abstract The bull is a factor of genetic and economic importance in cattle breed, since the next generations will depend on it; therefore, the evaluation of the seminal quality and the cryopreservation of its genetic material are essential. The aim of the study was to evaluate the effect of two dilution temperatures on the quality of semen from zebuine cattle from the Peruvian Tropics. The samples were placed in a water bath at 34°C and the macroscopic and microscopic characteristics of semen were analyzed. Only the ejaculates with >60% motility and <20% abnormalities were processed, separating them into two treatments. T1 consisted of a 1:1 predilution at 34°C, followed by a final dilution of 30 minutes by adding the dilutor at 34°C. T2 consisted of a 1:1 predilution at 34°C and after 30 minutes of stabilization, refrigeration was carried out together with the dilutor, in order to carry out the final dilution at 5°C. The seminal quality was analyzed after 16 hours of refrigeration. The percentage of vitality in T1 (80.89%) was greater than in T2 (71.22%) (p<0.05), the positive reaction to the hypoosmotic problem was greater in T1 (71.11%) than in T2 (60%) (p<0.05). Acrosomal integrity and morphometric features did not vary according to treatments. In conclusion, the initial and final dilution at 34°C in Gyr bulls positively influences the semen quality before the freezing of semen packets.

ABSTRACT The environment is vital to the agricultural sector since it can cause adversities throughout the entire productive chain. This study evaluated the geographical distribution of zebu breeds in Brazil and correlated their occurrence with environmental variables and the human development index. Herds of purebred zebu cattle (Bos indicus) in Brazil were classified as beef, dairy, and dual-purpose breeds, and all breeds were spatialized in the ArcGIS program. Environmental (precipitation, temperature, relative humidity index) and the human development index (HDI) were examined. We conducted regression and logistic analyses. Zebu cattle showed a lower distribution in the Northeastern states compared to other locations, possibly due to harsh weather conditions, namely long periods of high temperatures and lower precipitation, directly affecting local livestock. Beef breeds were evenly spread throughout the country in regions influenced by environmental variables of higher precipitation, normalized difference vegetation index (NDVI), temperature, relative humidity (RH), and temperature humidity index (THI), as well as properties without smallholder farmers and rivers and streams with riparian vegetation. The regions for dual-purpose and dairy breeds were predominantly cultivated with cutting forages (e.g., sugarcane - Saccharum officinarum), with the integration of crops, livestock and/or forestry (i.e., combining different activities in the same area) and areas with a rotational grazing system (i.e., grazing management), indicating a higher occupation in fertile lands. The Gir breed, the only dairy breed evaluated in this study, was seen in establishments with smallholder farmers, characterized by small to medium farms, and in regions at higher altitudes.

RESUMO: Os objetivos foram analisar as informações genealógicas de bovinos Gir (GY) e Nelore (NL) da Costa Rica. Foram considerados: integridade do pedigree (GY, 13272; NL, 18153); número de gerações completas, máximas traçadas e equivalentes completas; endogamia (FI); intervalo de geração (GI) por meio de quatro rotas de seleção; razão genética aditiva média (AGR); número efetivo de fundadores (fe); número efetivo de ancestrais (fa); tamanho efetivo da população (Ne). A análise foi realizada com o software ENDOG. A proporção máxima de pais, avós e bisavós desconhecidos foi de 18,6%, 39,9% e 59,3%, respectivamente. O FI médio para NL foi de 8,87% e 2,85% no GY. A média da população consanguínea (%) e FI foi de 53,9 e 16,5% em NL, 28,9 e 9,9% em GY. Os valores médios e máximos de AGR para NL foram 3,5 e 12,8, 1,4 e 5,6 no GY. Os fe e fa para NL foram 65,0 e 38,0, no GY 145,7 e 59,0. O Ne indicou aumentos de FI na faixa de 1 a 2% no GY, para NL superiores a 2%, com status de cuidado para acompanhar a evolução de F e AGR e suas possíveis implicações no melhoramento genético. O IG variou de 6,3 a 7,9 anos com média geral de 6,9 anos. Esses resultados mostram um resumo do manejo genético e reprodutivo realizado por esses criadores. RESUMO (GY (NL Rica considerados 13272 18153 18153) completas (FI) GI (GI seleção (AGR) (fe) (fa) Ne. . (Ne) ENDOG pais 186 18 6 18,6% 399 39 9 39,9 593 59 3 59,3% respectivamente 887 8 87 8,87 285 2 85 2,85 % (% 539 53 53, 165 16 5 16,5 289 28 28, 99 9,9 35 3, 128 12 12,8 14 4 1, 56 5, 650 65 0 65, 380 38 38,0 1457 145 7 145, 590 59,0 63 6, 79 7, 69 criadores 1327 1815 (FI (AGR (fe (fa (Ne 18,6 39, 59,3 88 8,8 2,8 ( 16, 9, 12, 38, 59, 132 181 18, 8, 2, 13

ABSTRACT: The objectives were to analyze the genealogical information of Gyr (GY) and Nelore (NL) cattle from Costa Rica. Analyzed: pedigree integrity (GY, 13272; NL, 18153); number of complete, maximum traced and equivalent complete generations; inbreeding (FI); generation interval (GI) through four selection routes; average additive genetic ratio (AGR); effective number of founders (fe); effective number of ancestors (fa); effective population size (Ne). The analysis was performed with the ENDOG software. The maximum proportion of unknown parents, grandparents, and great-grandparents was 18.6%, 39.9%, and 59.3%, respectively. The average FI for NL was 8.87% and 2.85% in GY. The average consanguineous population (%) and FI was 53.9 and 16.5% in NL, 28.9 and 9.9% in GY. The average and maximum values of AGR for NL were 3.5 and 12.8, 1.4 and 5.6 in GY. The fe and fa for NL were 65.0 and 38.0, in GY 145.7 and 59.0. The Ne indicated increases in FI in the range of 1 to 2% in GY, for NL greater than 2%, with a status of care to monitor the evolution of F and AGR and their possible implications in genetic improvement. The GI ranged from 6.3 to 7.9 years with a general average of 6.9 years. These results show a summary of the genetic and reproductive management those breeders have carried out. ABSTRACT (GY (NL Rica Analyzed 13272 18153 18153) generations (FI) (GI routes (AGR) (fe) (fa) Ne. . (Ne) software parents grandparents greatgrandparents great 186 18 6 18.6% 399 39 9 39.9% 593 59 3 59.3% respectively 887 8 87 8.87 285 2 85 2.85 % (% 539 53 53. 165 16 5 16.5 289 28 28. 99 9.9 35 3. 128 12 12.8 14 4 1. 56 5. 650 65 0 65. 380 38 38.0 1457 145 7 145. 590 59.0 improvement 63 6. 79 7. 69 out 1327 1815 (FI (AGR (fe (fa (Ne 18.6 39.9 59.3 88 8.8 2.8 ( 16. 9. 12. 38. 59. 132 181 18. 39. 8. 2. 13