Resumo A determinação acurada do consumo individual é um parâmetro importante para avaliação do valor nutritivo da dieta e permite o fornecimento adequado de alimentos, conforme as exigências nutricionais de cada animal. Quando há impossibilidade da sua mensuração pelo método direto, o consumo pode ser calculado a partir da produção fecal estimada por indicadores e pela digestibilidade in vitro da matéria seca (DIVMS) da dieta. Foi objetivo deste estudo avaliar os indicadores externos dióxido de titânio (TiO2) e hidroxifenilpropano enriquecido e modificado (LIPE®) nas estimativas de consumo de matéria seca (MS). Foram utilizadas quatro vacas multíparas Holandês × Gir com média de 60 dias em lactação e 488 kg de peso corporal. Os animais foram alojados em estábulo tipo free stall e alimentados com dietas à base de silagem de cana-de-açúcar suplementada com concentrado composto de milho moído, farelo de algodão e 0%, 5%, 10% e 15% de caroço de algodão (base da MS). Adotou-se delineamento quadrado latino 4 x 4. O consumo foi determinado pela razão entre a produção fecal estimada pelos indicadores e pela DIVMS da dieta, sendo as fezes coletadas diretamente na ampola retal, duas vezes por dia, por um período de sete dias. Não houve diferença (P>0,05) nos consumos de MS estimados pelos indicadores TiO2 e LIPE® (10,3 vs. 12,1; 11,1 vs. 12,5; 10,2 vs. 12,9; e 12,7 vs. 10,9 kg/vaca/dia em relação ao consumo mensurado, para as dietas com 0%, 5%, 10% e 15% de inclusão do caroço de algodão, respectivamente). Os indicadores externos LIPE® e TiO2 mostraram-se adequados para estimar o consumo de MS das vacas. Independente da dieta oferecida, ambos mostraram que podem ser utilizados em substituição ao indicador externo óxido crômico, pois, as estimativas de consumo estimadas por eles não diferiram do consumo mensurado no cocho. alimentos animal direto (DIVMS TiO (TiO2 LIPE (LIPE® MS. . (MS) 6 48 corporal canadeaçúcar cana açúcar moído 0 0% 5 5% 10 15 MS) Adotouse Adotou se retal dia P>0,05 P005 P 05 (P>0,05 10,3 103 3 (10, vs 12,1 121 12 1 111 11 11, 12,5 125 102 2 10, 12,9 129 9 127 7 12, 109 kgvacadia vaca respectivamente. respectivamente respectivamente) mostraramse oferecida crômico pois cocho (TiO (LIPE (MS P>0,0 P00 (P>0,0 (10 P>0, P0 (P>0, (1 P>0 (P>0 ( P> (P> (P

Abstract The accurate determination of individual dry matter intake (DMI) is an important parameter for evaluating the nutritional value of a diet and allows for an adequate supply of food according to the nutritional requirements of each animal. When it is not possible to measure this parameter using a direct method, the DMI can be estimated based on faecal production markers and the in vitro digestibility of dry matter (IVDMD) of the diet. The objective of this study was to evaluate the effects of the external marker titanium dioxide (TiO2) and enriched and modified hydroxyphenylpropane (LIPE®) on DMI. Four multiparous Holstein × Gyr cows with an average of 60 days in milk and 488 kg of body weight were used. The animals were housed in a free stall barn and fed diets based on sugarcane silage supplemented with concentrate composed of ground corn, cottonseed meal and 0%, 5%, 10% and 15% whole cottonseed on a dry matter (DM) basis. A 4 x 4 Latin square design was adopted. The DMI was determined by the ratio between the faecal production estimated by the markers and the IVDMD of the diet, with faeces collected by rectal grabbing twice a day for a period of seven days. There was no difference (P>0.05) in the DMI estimated by the external markers TiO2 and LIPE® (10.3 vs. 12.1; 11.1 vs. 12.5; 10.2 vs. 12.9; and 12.7 vs. 10.9 kg/cow/day in relation to the measured DMI for diets with 0%, 5%, 10% and 15% inclusion of whole cottonseed, respectively). The external markers LIPE® and TiO2 proved to be suitable for estimating cow DMI. Regardless of the diet offered, both external markers can be used to replace the external marker chromic oxide, as the DMI estimated by them did not differ from the DMI measured in the trough. (DMI animal method (IVDMD TiO (TiO2 LIPE (LIPE® 6 48 corn 0 0% 5 5% 10 15 DM (DM basis adopted P>0.05 P005 P 05 (P>0.05 10.3 103 3 (10. vs 12.1 121 12 1 111 11 11. 12.5 125 102 2 10. 12.9 129 9 127 7 12. 109 kgcowday respectively. respectively . respectively) offered oxide trough (TiO (LIPE P>0.0 P00 (P>0.0 (10 P>0. P0 (P>0. (1 P>0 (P>0 ( P> (P> (P

RESUMEN En condiciones del trópico colombiano es necesario establecer estrategias de alimentación que permitan aumentar la productividad a bajo costo. El objetivo de esta investigación fue evaluar el efecto de la suplementación con ensilados de totumo, mango, guayabo de monte sobre la digestibilidad in vitro, degradabilidad y parámetros productivos en vacas doble propósito. El estudio fue realizado en la finca La Florida, ubicada, en el municipio de Puerto Boyacá, se usaron 32 vacas (Gyr x Holstein) con peso promedio de 460 ±35 kg en primer tercio de lactación, distribuidas en cuatro (4) grupos de ocho (8) cada uno, conformados de la siguiente manera: T1: grupo control: sin ensilajes; T2: ensilaje de Guayabo de monte; T3: ensilaje de Totumo y T4: ensilaje de Mango común. Todas las vacas permanecieron en pastoreo rotacional con Brachiaria decumbens, agua a voluntad y sal mineralizada. Se analizó el efecto del tratamiento, el tiempo y su interacción, para ello se usó el comando PROC MIXED del software SAS 9.2 (2002), la diferencias entre promedios se realizó mediante prueba de Tukey-Kramer, con nivel de significancia del 5 %. No hubo diferencias (p<0,05) en la producción diaria de leche entre los tratamientos evaluados, sin embargo, el porcentaje de proteína en leche fue mayor (p<0,05) en los tratamientos T2 y T4. EL NUL fue mayor en el T2 y menor en el T4. El consumo de ensilajes fue mayor (p<0,05) en el T4 y la condición corporal mostró ser mejor para los tratamientos T2 y T4, finalmente para los parámetros de degradabilidad y digestibilidad in vitro, los tratamientos T2, T3 y T4 obtuvieron los mayores valores respectivamente. La suplementación de vacas doble propósito con ensilajes de frutos del bosque húmedo tropical mejora la proteína de la leche y la condición corporal de las vacas. Los ensilados estudiados, poseen alta tasa de degradación y digestibilidad In vitro, representando una alternativa de alimentación en los rumiantes.

ABSTRACT In the Colombian tropic, it is necessary to establish feeding strategies that increase productivity and reduce costs. This research aimed to evaluate the effect of totumo, mango, and wild guava silage on in vitro digestibility, degradability, and productive parameters in dual-purpose cows. This study was carried out on a farm located in the municipality of Puerto Boyacá. Thirty-two Gyr x Holstein cows (Body weight = 460 ± 35 kg) in early lactation were enrolled and distributed in four groups of eight individuals: T1: control group: no silage; T2: Wild guava silage; T3: Totumo silage and T4: Mango silage. All the cows remained in a rotational grazing system with Brachiaria decumbens, water, and a salt-based mineral supplement ad libitum. There were no differences (p>0,05) in the daily milk production. However, protein levels in milk were higher (p<0,05) in the T2 and T4 treatments. NUL was more elevated in T2 and lower in T4. Silage consumption was higher (p<0,05) in T4, and the body condition score was higher for T2 and T4. For the degradability and digestibility parameters in vitro, treatments T2, T3, and T4 obtained the highest values. Fruits silage supplementation on dual-purpose cows with silage fruits can increase milk protein levels and body condition score. Those silages have a high rate of degradation and in vitro digestibility, representing a feeding alternative for ruminants.

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 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

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 objective of this research was to identify the influence of the evaporative adiabatic cooling system (EACS) on the thermal comfort and productive responses of dairy cattle, through multivariate analysis by principal components (PC), in the summer and winter seasons of the semiarid region of Pernambuco, Brazil. The data came from an experiment that included 16 multiparous lactating cows (7/8 Holstein-Gyr), randomly distributed in 4 sets, with 4 experimental phases and 4 treatments (0, 10, 20, and 30 min.). The multivariate analysis was carried out through PC for the thermal comfort indices, physiological variables, and milk production and composition. The highest milk production in the summer season was obtained for animals exposed to the cooling system for 30 min. In the winter season in the morning period, the use of the EACS for 10 min. was sufficient for improvements in milk production. The times of exposure to EACS caused changes in the composition of milk, for both seasons. Principal component analysis made it possible to verify a positive correlation of evaporative cooling with thermal comfort, physiological responses, and production and composition of milk of lactating cows. ABSTRACT (EACS cattle PC, , (PC) Pernambuco Brazil 1 7/8 78 7 8 (7/ HolsteinGyr, HolsteinGyr Holstein Gyr Holstein-Gyr) sets 0, 0 (0 20 3 min.. min . min.) indices variables period (PC 7/ (7 Holstein-Gyr ( 2

Abstract The complete rearing cycle of dairy calves is not yet widely adopted by rural producers, possibly because they do not perceive these animals as potential meat producers or are unaware of their production capabilities. This study aimed to assess the economic viability of rearing dairy calves through their entire growth cycle. Sixteen Holstein × Gyr crossbred animals were assessed, originating from dairy farming, with an average initial weight of 40.67 ± 5.27 kg and slaughtered at 10 months of age, reaching a final weight of 320.4 ± 45.87 kg. These calves were reared in a feedlot system and received a mash diet without the inclusion of roughage. The experiment was conducted on a farm primarily focused on dairy farming, situated in the municipality of Turvânia, GO, Brazil. Economic evaluations were conducted at the conclusion of the production cycle, with the calculation of the value of the arroba (@ = 15 kg) produced. Data were analyzed using a production cost structure methodology, which included effective operating cost, total operating cost, and total cost. The following economic indicators were examined: gross revenue, gross margin, net margin, and the break-even point. Results were highly promising, demonstrating a profit from raising dairy male calves, with a net margin per animal of BRL 321.50. Additionally, these animals displayed noteworthy potential for weight gain and carcass quality. A total of 149.19 @ were produced, averaging 9.32 @ per animal, with a production cost of BRL 105.52, encompassing expenses such as milk consumption, concentrate diet, and labor, which amounted to BRL 1.18 per month per animal. These findings underscore the economic feasibility of this rearing system. capabilities assessed farming 4067 40 67 40.6 527 5 27 5.2 1 age 3204 320 4 320. 4587 45 87 45.8 roughage Turvânia GO Brazil ( produced methodology examined revenue breakeven break even point promising 32150 321 50 321.50 Additionally quality 14919 149 19 149.1 932 9 32 9.3 10552 105 52 105.52 consumption labor 118 18 1.1 406 6 40. 2 5. 458 8 45. 3215 321.5 1491 14 149. 93 3 9. 1055 105.5 11 1. 321. 105.

Resumo O ciclo completo de bezerros leiteiros ainda não é muito utilizado pelos produtores rurais, por não considerarem esses animais como produtores de carne, ou pelo motivo de não conhecerem o potencial de produção. Objetivou-se avaliar os índices econômicos do ciclo completo em bezerros leiteiros. Foram avaliados 16 animais mestiços Holandês x Gir, oriundos da atividade leiteira com peso médio inicial de 40,67 ± 5,27 kg, abatidos aos 10 meses de vida com peso final de 320,4 ± 45,87 kg, mantidos em sistema de confinamento recebendo dieta farelada sem o uso de volumoso. O experimento foi conduzido em uma propriedade com principal fonte renda à atividade leiteira, no munícipio de Turvânia-GO. As avaliações econômicas foram feitas no final do ciclo de produção, com o cálculo do valor da arroba (@) produzida, para a interpretação dos dados utilizou-se a metodologia da estrutura de custos de produção: custo operacional efetivo, custo operacional total e custo total. Foram analisados os seguintes indicadores econômicos: receita bruta, margem bruta, margem líquida e ponto de equilíbrio. Os resultados obtidos foram satisfatórios, ao apresentarem lucro com utilização dos machos leiteiros, com Margem Líquida por animal de R$ 321.50, além do potencial de ganho de peso e qualidade de carcaça desses animais. Foram produzidas 149,19 @ com média de 9,32 @ animal-¹, com o custo de produção de R$ 105,52 incluindo o leite consumido, dieta concentrada e a mão-de-obra no valor de R$ 1,18 ao mês por animal, demonstrando viabilidade econômica do sistema. rurais carne Objetivouse Objetivou se 1 Gir 4067 40 67 40,6 527 5 27 5,2 kg 3204 320 4 320, 4587 45 87 45,8 volumoso TurvâniaGO. TurvâniaGO Turvânia GO. GO Turvânia-GO (@ produzida utilizouse utilizou efetivo bruta equilíbrio satisfatórios R 32150 321 50 321.50 14919 149 19 149,1 932 9 32 9,3 animal¹, animal¹ ¹, ¹ animal-¹ 10552 105 52 105,5 consumido mãodeobra mão obra 118 18 1,1 406 6 40, 2 5, 458 8 45, ( 3215 321.5 1491 14 149, 93 3 9, animal- 1055 105, 11 1, 321.

Resumen Diversos estudios han comprobado que la progesterona tiene un efecto directo en la calidad ovocitaria y el desarrollo inicial embrionario. El objetivo de este estudio fue evaluar el efecto de la concentración de la progesterona (P4) plasmática en el desarrollo de embriones in vitro en vacas de raza Bos taurus taurus (Holstein) y Bos taurus indicus (Gyr). Se utilizaron vacas Holstein y Gyr multíparas, presincronizadas con la aplicación de dos dosis de D-cloprostenol con intervalo de once días. Posteriormente, se distribuyeron en uno de tres grupos experimentales inducidos a diferentes niveles plasmáticos de progesterona. El grupo control fue sincronizado utilizando únicamente D-cloprostenol sin progesterona exógena, el grupo progesterona baja recibió un implante auricular de norgestomet de segundo uso y al grupo progesterona alta se le aplicaron dos implantes auriculares de norgestomet nuevos. Los resultados evidencian que la concentración plasmática de progesterona fue significativamente diferente (P < 0,05) tanto para las vacas Holstein (0,22 ± 0,15, 2,23 ± 0,17 y 5,32 ± 0,22 ng/mL) como para las vacas Gyr (0,24 ± 0,19, 2,05 ± 0,17, 4,85 ± 0,20 ng/mL) entre los grupos control, progesterona baja y progesterona alta, respectivamente. Las vacas Gyr presentaron diferencia (P < 0,05) en la tasa de clivaje del grupo progesterona baja en relación con los grupos control y progesterona alta (87,9 % ± 0,11 vs 77,5 % ± 0,13 y 76,4 % ± 0,10, respectivamente) y en la variable tasa de blastocistos del grupo progesterona baja (48,3 % ± 0,16) en relación con el grupo control (35,8 % ± 0,10) y el grupo progesterona alta (30,4 % ± 0,20). Se concluye que la progesterona tuvo efecto sobre el desarrollo embrionario en vagas de raza Gyr, el cual no se evidenció en las vacas de raza Holstein.

Abstract Studies have shown that progesterone has a direct effect on oocyte quality and early embryonic development. The objective of this study was to evaluate the effect of plasma progesterone (P4) concentration on in vitro embryo development in Bos taurus taurus (Holstein) and Bos taurus indicus (Gyr) cows. Multiparous Holstein and Gyr cows were used, and they were presynchronized with the application of two doses of D-cloprostenol with an interval of 11 days. They were latter distributed in one of three experimental groups induced to different plasma levels of progesterone: control group was synchronized using only D-cloprostenol without exogenous progesterone, low progesterone group received an auricular implant of norgestomet of second use, and high progesterone group received two new auricular implants of norgestomet. The plasma progesterone concentration was significantly different (P < 0.05) for both Holstein cows (0.22 ± 0.15, 2.23 ± 0.17 and 5.32 ± 0.22 ng/mL) and Gyr cows (0.24 ± 0.19, 2.05 ± 0.17, 4.85 ± 0.20 ng/mL) between control, low progesterone, and high progesterone groups respectively. Gyr cows presented differences (P < 0.05) in the cleavage rate of the low progesterone group in relation to the control and high progesterone groups (87.9 % ± 0.11 vs. 77.5 % ± 0.13 and 76.4 % ± 0.10, respectively) and in the variable blastocyst rate of the low progesterone group (48.3 % ± 0.16) in relation to the control group (35.8 % ± 0.10) and the high progesterone group (30.4 % ± 0.20). It is concluded that there is an effect of progesterone on embryonic development of Gyr cows. However, this effect is not evidenced in Holstein cows.

Resumo O objetivo deste trabalho foi comparar os principais modelos lineares e não lineares usados para descrever curvas de lactação e avaliar a não linearidade dos modelos não lineares, para obter o modelo mais adequado para a descrição das curvas de lactação da raça Girolando. Foram utilizados dados de 165 lactações de 89 vacas 3/4 Holandesas + 1/4 Gir, tendo-se calculado a produção média a cada 20 dias até 310 dias de lactação. Foram comparados 17 modelos de curvas de lactação disponíveis na literatura. A seleção do melhor modelo foi feita com base nas medidas de curvatura de Bates & Watts, no vício de Box, no coeficiente de determinação ajustado, no critério de informação de Akaike e no desvio-padrão residual. O modelo linear de Cobuci estimou um pico de produção de 16,7 kg aos 40 dias de lactação, enquanto o modelo não linear de Wood estimou um pico de produção de 16,8 kg aos 41 dias de lactação e persistência de 6,82. As medidas de não linearidade foram as mais adequadas para selecionar o modelo não linear mais adequado para a descrição das curvas de lactação. Para descrever as curvas de lactação da raça Girolando, o modelo linear mais adequado é o de Cobuci e o não linear é o de Wood.

Abstract The objective of this work was to compare the main linear and nonlinear models used to describe lactation curves and to evaluate the nonlinearity of the nonlinear models, in order to obtain the most adequate model to describe the lactation curves of the Girolando breed. Data from 165 lactations of 89 3/4 Holstein + 1/4 Gyr cows were used, and average yield was calculated every 20 days up to 310 days of lactation. Seventeen models of lactation curves available in the literature were compared. The selection of the best model was based on the curvature measures of Bates & Watts, the bias of Box, adjusted coefficient of determination, Akaike’s information criterion, and residual standard deviation. The linear model of Cobuci estimated a yield peak of 16.7 kg at 40 days of lactation, whereas the nonlinear model of Wood estimated a yield peak of 16.8 kg at 41 days of lactation and a persistence of 6.82. Nonlinearity measures were the most appropriate for selecting the most suitable nonlinear model for the description of lactation curves. To describe the lactation curves of the Girolando breed, the most suitable linear model is that of Cobuci and the nonlinear model is that of Wood.

ABSTRACT The objective of this study was to evaluate the breed and heterosis effects on reproductive traits, test-day milk yield, and 305-day milk yield in different lactations of crossbred Girolando cows. Data consisted of test-day milk yield records of first (118,831 records), second (63,227), and third lactation (44,512) and their relative productive (test-day milk yield, 305-day milk yield, and lactation length) and reproductive (age at first calving, calving interval, days open, and dry period) records of 35,582 Girolando cows from Brazil, collected from 1998 to 2014. The heterosis effect of the evaluated traits in Girolando cattle was estimated by MIXED procedure in SAS. Girolando cows showed a negative (favorable) and significant heterosis effect for reproductive traits. The dry periods between the first and second calving and between the second and third calving showed the greatest gains in heterosis (21.93 and 10.41%, respectively). All the evaluated productive traits showed a significant and similar heterosis effect between the three lactations. The use of crossbreeding strategies between the Holstein and Gyr breeds, instead of using the pure breed, is indeed a good alternative to increase the economic efficiency of the dairy activity in the different production systems in tropical environments.

RESUMO O período de transição em vacas leiteiras aumenta o suprimento de oxigênio aos tecidos e a produção de espécies reativas de oxigênio. Junto com o comprometimento do sistema antioxidante, gera estresse oxidativo que pode estar ligado ao desenvolvimento de diversas doenças. Este estudo teve como objetivo avaliar o estresse oxidativo em 35 novilhas leiteiras Gir durante o período periparto. Foram analisados ácido úrico, cobre, ferro, zinco, albumina, bilirrubina total, superóxido dismutase (SOD) e glutationa peroxidase (GSH-Px). Um modelo linear com distribuição de Poisson foi aplicado usando o procedimento GENMOD. A primeira medida (30d antes do parto) foi considerada como referência (T0) e as amostras foram coletadas 16 dias antes do parto (T1) e 7 (T2), 14 (T3), 28 (T4) e 42 dias pós-parto (T5). Cobre, zinco e albumina variaram dentro da faixa de referência, apesar de um aumento no cobre de 45,92% no T3. Os níveis de ácido úrico aumentaram durante o período de transição, sem diferença significativa até 16 dias pré-parto, quando foi observado um aumento de 67,57%, sendo sua maior concentração observada em T4. A SOD teve um aumento maior (300%) do que GSH-Px (36%) no final do período experimental, acompanhada por adaptações bioquímicas para garantir uma resposta antioxidante eficaz. Dessa forma, pode-se concluir que o período periparto causa estresse oxidativo em novilhas leiteiras Gir.

ABSTRACT O período de transição em vacas leiteiras aumenta o suprimento de oxigênio aos tecidos e a produção de espécies reativas de oxigênio. Junto com o comprometimento do sistema antioxidante, gera estresse oxidativo, que pode estar ligado ao desenvolvimento de diversas doenças. Este estudo teve como objetivo avaliar o estresse oxidativo em 35 novilhas leiteiras Gir, durante o período periparto. Foram analisados ácido úrico, cobre, ferro, zinco, albumina, bilirrubina total, superóxido dismutase (SOD) e glutationa peroxidase (GSH-Px). Um modelo linear com distribuição de Poisson foi aplicado usando o procedimento GENMOD. A primeira medida (30d antes do parto) foi considerada como referência (T0), e as amostras foram coletadas 16 dias antes do parto (T1) e sete (T2), 14 (T3), 28 (T4) e 42 dias pós-parto (T5). Cobre, zinco e albumina variaram dentro da faixa de referência, apesar de ter havido aumento no cobre de 45,92% no T3. Os níveis de ácido úrico aumentaram durante o período de transição, sem diferença significativa até 16 dias pré-parto, quando foi observado aumento de 67,57%, sendo sua maior concentração observada em T4. A SOD teve um aumento maior (300%) do que a GSH-Px (36%) no final do período experimental, acompanhada por adaptações bioquímicas para garantir uma resposta antioxidante eficaz. Dessa forma, pode-se concluir que o período periparto causa estresse oxidativo em novilhas leiteiras Gir.

Abstract The aims were to evaluate the effect of breed on the genetic polymorphism kappa-casein, physicochemical composition of milk and Coalho cheese, and on cheese yield; and to evaluate the effect of different periods of storage on sensorial acceptance of the Coalho cheese obtained from milk of Guzerat, Gyr and Sindi cows. Twenty (20) cows of Zebu breeds were selected, from which it was obtained the frequency values of the genetic polymorphism kappa-casein. Milk were submitted to fat, protein, lactose, non-fat solids and total solids, electrical conductivity analysis and somatic cell count. Cheeses were submitted to fat, protein, total solids, pH, moisture and yield (g TS/L) analysis. Attributes appearance, aroma, texture and flavor were judged at the 1st, 25th and 46th day of storage. There was a total frequency of 0.70 for genotype AA, 0.30 for genotype AB. There was no significant difference in milk composition among the studied breeds. However, there were differences in the physicochemical composition (with the exception of the protein) and the yield of the cheeses, but all the breeds showed a similar real yield. It was found effect of the storage period on the cheeses sensory attributes in the different breeds, with the exception of the appearance. The milk of the Guzerat, Gyr and Sindi breeds constitute an excellent raw material for the production of curd cheese and ensures a satisfactory sensorial acceptance of the product at the 1st, 25th and 46th days of storage.

Resumen Los objetivos fueron evaluar el efecto de la raza sobre el polimorfismo genético de la kappa-caseína, la composición fisicoquímica de la leche y del queso Coalho, y el rendimiento del queso, así como evaluar el efecto de diferentes periodos de almacenamiento sobre la aceptación sensorial del queso Coalho obtenido a partir de leche de vacas Guzerat, Gyr y Sindi. Se seleccionaron veinte (20) vacas de razas cebú y se obtuvieron sus valores de frecuencia del polimorfismo genético de la kappa-caseína. La leche se sometió a un análisis de grasa, proteína, lactosa, sólidos no grasos y sólidos totales, conductividad eléctrica y cuenta de células somáticas. Los quesos se sometieron a análisis de grasa, proteína, sólidos totales, pH, humedad y rendimiento (g ST/L). Se evaluaron los atributos apariencia, aroma, textura y sabor en los días 1, 25 y 46 de almacenamiento. La frecuencia total fue de 0.70 para el genotipo AA y 0.30 para el genotipo AB. No hubo diferencias significativas en la composición de la leche entre las razas estudiadas. Sin embargo, hubo diferencias en la composición fisicoquímica (exceptuando la proteína) y el rendimiento de los quesos; pero todas las razas mostraron un rendimiento real similar. El periodo de almacenamiento tuvo efectos observables sobre los atributos sensoriales de los quesos en las diferentes razas, con la excepción de su apariencia. La leche de las razas Guzerat, Gyr y Sindi constituye una excelente materia prima para la producción de cuajada y garantiza una aceptación sensorial satisfactoria del producto a los días 1, 25 y 46 de almacenamiento.

ABSTRACT A case of an imperforate Gyr calf born in a ranch is reported in Cundinamarca, Colombia. The calf was in an agonizing state, it had urinary and fecal tenesmus. Due to animal welfare conditions, euthanasia was performed. Congenital atresia ani, agenesis of the vulva, rectovaginal fistula, urosalpinx-urometrocolpos and coprosalpinxcoprometrocolpos was present.

RESUMEN Se reporta un caso de un ternero Gyr imperforado nacido en un rancho en Cundinamarca, Colombia. El ternero estaba en una etapa agonizante, tenía tenesmo urinario y fecal. Debido a las condiciones de bienestar animal, se realizó la eutanasia. Se encontró atresia anal congénita, agenesia de vulva, fístula rectovaginal, urosalpinxurometrocolpos y coprosalpinx-coprometrocolpos.

ABSTRACT The objective of this study was to estimate the breed, heterosis, and recombination effects on different components of the lactation curve of Girolando cattle. The dataset used consisted of 12,121 purebred cows of Holstein (H) and Gyr (G) breeds, and six H×G crossbred cows (Girolando). The model used presents random effects of herd and cow, regression coefficient associated with linear effect of proportion of H breed, regression coefficient associated with the linear effect of heterosis between H and G breeds, regression coefficient associated with the linear effect of recombination between H and G breeds, and random effect of residual. Dijkstra's (DJ), Nelder's (ND), Wilmink's (WL), and Wood's (WD) models were tested to fit production records of these different genetic groups. These models were then tested according to evaluation criteria of quality of fit (AIC, BIC, and RMSE), and the two best models (WD and WL) were chosen for estimation of 305-day milk yield (MY305), peak yield, time to peak, and persistency of milk yield. The breed effect was significant for all traits and components of the lactation curve. The heterosis effect was significant for all traits, and was more significant for MY305 (945.62±79.17 kg). Peak yield was the component of lactation curve that presented the most significant heterosis effect, partially explaining the heterosis effect (12 to 21%) found for MY305. The recombination effect was positive only for lactation period and time to peak of lactation in Girolando cows.

ABSTRACT. The objective of this study was to evaluate productive, nutritional, and economic traits in lactating cows on pasture fed diets with different cation-anion balances (DCAB). Ten lactating – Holstein × ¼ Dairy Gyr cows in the middle third of lactation, at an average age of 70 ± 4.6 months and an average body weight of 400 ± 55.2 kg, were distributed into five treatments in a 5 × 5 Latin square experimental design with two simultaneous squares. Treatments consisted of diets with DCAB of +237, +258, +294, +347, or +419 mEq dry matter (DM). No effects of intake were observed. There was no significant effect of DCAB on milk yield. The milk protein content was not influenced by the DCAB. Body condition score was not significantly affected by the DCAB. The apparent digestibilities of dry matter and nutrients (crude protein, neutral detergent fiber, ether extract, non-fibrous carbohydrates, and total digestible nutrients) were not affected by the DCAB. Marginal rate of return did not show significant differences. Under good conditions of pasture, forage availability, and quality associated with the lactation phases of the cows, all diets were efficient in milk production, dry matter intake, and digestibility. However, in economic terms, the most attractive DCAB was +237 mEq kg-1 DM.

ABSTRACT. To evaluate the bromatological composition and ruminal degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of Xaraés palisade grass (Urochloa brizantha ‘Xaraes’ syn Brachiaria brizantha) under grazing in integrated crop, livestock (ICL), and forest (ICLF) systems, we conducted an in situ degradability trial in randomized blocks with three non-lactating 3/4 Gyr × 1/4 Holstein cows, provided with ruminal cannula. The management of Xaraés palisade grass was similar in both systems, differing only regarding shading in the ICLF system provided by eucalyptus trees (average 65% crown cover). Grass samples were incubated for 0, 3, 6, 9, 12, 24, 36, 48, 72, and 96 hours. Considering the passage rate 2% h-1, the Xaraés palisade grass of ICL system had greater NDF effective degradability in relation to ICLF (46.38 vs 44.98%). However, the palisade grass CP potential degradability was greater in the ICLF than in the ICL system (68.92% vs. 65.40%). The presence of trees in the pasture has effect on nutritional traits of the Xaraés palisade grass, increasing its protein content and degradability and reducing its fiber degradability.