Low-density dispersive liquid-liquid microextraction with a subsequent esterification step was proposed in this study for the determination of linoleic acid and stearic acid in sheep blood serum samples. The method developed aimed to quickly and efficiently extract and esterify both fatty acids with subsequent analysis by gas chromatography/flame ionization detection. The extraction method was optimized with Scheffé’s polynomial model for three-component mixtures. The method was validated according to the parameters established by Eurachem Guide (2014). The optimal extraction conditions for LD-DLLME were 1400 µL of dispersion medium (MgCl2 0.017%), 400 µL of extractor solvent (toluene) and 1200 µL of dispersion solvent (methanol). The method performance showed adequate selectivity, sensitivity and precision to be applied to real samples, with an average recovery of 98.54% for linoleic acid and 103.83% for stearic acid. LD-DLLME was superior to the traditional method of analysis, which has been used until now for the determination of fatty acids in blood serum samples from ruminants. The analysis of real samples showed that the developed method is efficient for monitoring these substances in ruminants.

ABSTRACT The objective of this study was to evaluate the effect of replacing ground corn (402 g kg−1 of dry matter) with rehydrated corn grain silage (RCGS; 425 g kg−1 of dry matter) in a flushing diet on follicular development in tropical Santa Inês ewes. Fifteen ewes were randomly assigned to one of two treatment groups: a diet with ground corn (control, n = 7) or a diet with RCGS (n = 8). The first day of the diets was designated d0, and the diets were fed for 30 days, up to two days after the end of the estrus synchronization protocol. The estrus synchronization protocol (intravaginal progestogen sponge for 11 days plus 300 IU eCG and 37.5 µg d-cloprostenol IM two days before sponge removal) started on d17 of the diets. The number and diameters of ovarian follicles ≥3 mm were assessed by ultrasound on the day before the diets were provided (d−1), on d14, and then daily from two days before sponge removal until ovulation or up to the eighth day after sponge removal. Blood samples were collected on days −1, 0, 6, 12, 18, 24, and 30 for glucose and urea analyses. There was no effect of the treatments on dry matter intake, plasma glucose, and urea nitrogen concentrations, or on the percentage of ewes that ovulated and on the number of ovulations. The number of follicles ≥3 mm did not differ between treatment groups; the number increased between d−1 and d14 and did not differ between d14 and d28. The diameter of ovulatory follicles at sponge removal, the interval from sponge removal to estrus, and the growth rate of the ovulatory follicles were greater in the RCGS group than in the control group, resulting in larger follicles at ovulation. Replacement of ground corn by RCGS in the flushing diet does not increase the number of ovulations but results in delayed onset of estrus and ovulation of larger follicles.

Resumo A conversão da vegetação nativa para áreas agrícolas modifica a dinâmica de troca de energia no sistema solo-planta-atmosfera. Dessa forma, o objetivo deste estudo foi avaliar o efeito da conversão de uma área de Cerrado em culturas agronômicas no balanço de energia e evapotranspiração no sul do Estado de Mato Grosso. O estudo foi conduzindo em áreas de cerradão, cerrado stricto sensu, mangueiral, cultura de teca, coqueiral e pastagem. O balanço de energia foi estimado pelo SEBAL (Surface Energy Balance Algorithm for Land), utilizando dados de estação meteorológica e imagens do sensor TM Landsat 5 obtida em 2010. O saldo de radiação apresentou menores valores em pastagem que em Cerrado. O fluxo de calor latente no Cerrado foi maior em até 60% com relação às culturas agronômicas. O fluxo de calor sensível nas áreas agrícolas foram 50% maior que áreas de Cerrado. O Cerradão e o mangueiral apresentaram menores valores de fluxo de calor no solo. Apesar desse estudo não representar todo o Cerrado de Mato Grosso, os resultados demonstraram o impacto da conversão do Cerrado em áreas agrícolas no balanço de energia.

Abstract The conversion of native vegetation to agricultural areas modifies the dynamics of energy exchange in the soil-plant-atmosphere system. Thus, the objective of this study was to evaluate the effect in energy balance and evapotranspiration in the southern state of Mato Grosso due to the conversion of a Cerrado area in agronomic crops. The study was leading in areas of Cerradão, Cerrado strictu sensu, mango grove, teak culture, coconut trees and pasture. The energy balance was estimated by SEBAL (Surface Energy Balance Algorithm for Land) using weather station data and images from Landsat 5 TM sensor obtained in 2010. The net radiation showed lower values in pasture than in the Cerrado. The latent heat flux in the Cerrado was higher by 60% in relation to agronomic crops. The sensible heat flux in agricultural areas were 50% higher than Cerrado areas. The Cerradão and Mangueiral showed lower heat flux values on the ground. Although this study does not represent the entire Cerrado of Mato Grosso, the results showed the impact of the Cerrado into agricultural areas in the energy balance.

ABSTRACT The objective of this study was to examine the effects of suckling schemes (continued, controlled, and total separation) and the type of pregnancy on performance and serum cortisol concentration in lambs. A total of 29 Santa Inês ewes and 40 lambs were used, and the randomized block design was applied in a split-plot scheme with a 3 × 2 factorial arrangement in the plot and time in the subplot. For controlled suckling, the diet was supplied twice daily during one hour, starting on their 10th day of life. Total and average daily intakes of concentrate dry matter of lambs that underwent total separation was higher than those of lambs under continued suckling. Lambs subjected to total separation demonstrated higher concentrate dry matter intake/weight gain ratio, lower total weight gain, lower average daily weight gain, and lower weaning weight than those subjected to continued and controlled suckling. Lambs from single pregnancy demonstrated higher weight gain and obtained higher weight at weaning. Lambs subjected to total separation have a developmental delay. However, the lower performance of lambs subject to total separation cannot be attributed to stress because there is a decrease in the serum cortisol concentration over time.

Resumo As transformações decorrentes do uso e ocupação do solo modifica o balanço radioativo à superfície. O objetivo do trabalho foi avaliar o impacto no saldo de radiação em função da alteração de uma área de Cerrado em área agrária no sul do Mato Grosso por meio de técnica de sensoriamento remoto. Imagens do sensor TM Landsat 5 adquiridas entre junho e outubro de 2011 foram utilizadas. As análises foram realizadas nos seguintes usos do solo: Cerrado, mata ciliar, cana-de-açúcar, soja, pastagem, solo exposto e água. A substituição da área de Cerrado por áreas agrícolas neste estudo alterou os índices biofísicos da superfície, devido à mudança na biomassa e nas propriedades óticas da superfície. O NDVI apresentou maiores valores na vegetação típica de Cerrado e Mata Ciliar e menores valores nas áreas agrícolas. A temperatura da superfície e o albedo da superfície apresentaram padrões inversos ao NDVI, com menores valores na vegetação típica de Cerrado e Mata Ciliar e maiores valores nas áreas agrícolas e solo exposto. A substituição do Cerrado por culturas agronômicas no sul do Mato Grosso diminuiu a energia disponível à superfície, indicado pelo saldo de radiação.

Abstract Changes resulting from land use and occupation modify the surface radioactive balance. This paper evaluated the impact on the net radiation caused by the conversion of a Cerrado area in an agricultural zone in the southern Mato Grosso using Landsat 5 TM sensor imagery acquired between June and October 2011. The analyses were performed of the following land use classes: Cerrado, riparian vegetation, sugarcane, soybean, pasture, bare soil and water. The replacement of Cerrado by agricultural areas changed the biophysical indices of the surface due to the change in biomass and the optical properties of the surface as observed in this study. The NDVI values were higher in the typical Cerrado vegetation and Riparian Forest than in agricultural areas. The surface temperature and the surface albedo showed an inverse pattern of NDVI, with lower values in the typical Cerrado vegetation and Riparian Forest and higher values in agricultural areas and bare soil. The replacement of Cerrado by cultivated crops in the south of Mato Grosso decreased the available energy at the surface, as indicated by the radiation balance.

Machos e fêmeas, Santa Inês puros (SI) e cruzados de matrizes Santa Inês com reprodutores das raças Texel (TxSI), Ile de France (IFxSI) e Bergamácia (BxSI), terminados em confinamento e abatidos aos 15, 25, 35 e 45kg de peso vivo. Após o abate, foram tomados os pesos das vísceras e analisado o crescimento alométrico. O pulmão dos machos BxSI cresceu em taxas mais elevadas que SI e TxSI. A tráqueia/esôfago dos machos SI e TxSI cresceu mais lentamente que dos IFxSI e BxSI. Os rins dos machos BxSI cresceram mais rápido comparado aos dos TxSI e IFxSI. O fígado das fêmeas TxSI cresceu em taxas mais elevadas quando comparadas às fêmeas dos outros grupos genéticos. Os machos e fêmeas do grupo TxSI apresentaram taxas de crescimento maiores para rúmen/retículo, respectivamente, comparado aos grupos SI e BxSI.

Males and females, including purebred Santa Inês lamb (SI) and crosses between Santa Inês dams and Texel (TxSI), Ile de France (IFxSI) and Bergamasca (BxSI) sires were feedlot finished and slaughtered at 15, 25, 35 and 45kg live weight. After slaughter, the following non- carcass components were weighed and calculated the allometric growth. Lungs of BxSI males grew faster than those of SI and TxSI. Trachea/esophagus in SI and TxSI males grew slower than IFxSI and BxSI. Kidneys BxSI males grew faster than TxSI and IFxSI. Livers of female TxSI lamb grew more rapidly than those of females in the other genetic groups. In both males and females, the rumen/reticulum grew faster in the TxSI group than SI and BxSI groups.

The effects of overfeeding with protein of different degradability on body condition, plasma urea nitrogen and progesterone concentrations, ovulation number and follicular dynamics were assessed in Santa Ines ewes. Twelve ewes were assigned to a randomized block design according to body weight and received overfeeding with soybean meal or with corn gluten meal or maintenance diet for 28 days before ovulation and during the next estrous cycle. Blood samples were taken on days 7, 14, 21, and 28 after the beginning of treatments for analysis of plasma urea nitrogen and on days 3, 6, 9, 12, and 15 into the estrous cycle for analysis of plasma urea nitrogen and progesterone. Follicular dynamics was monitored daily by ultrasound during one estrous cycle. Dry matter and crude protein intake, weight gain, plasma urea nitrogen concentration before ovulation, number of ovulations, diameter of the largest follicle of the 1st and of the 2nd waves and the growth rate of the largest follicle of the 1st wave were higher in the ewes that received overfeeding. The growth rate of the largest follicle of the 3rd wave was higher in the ewes fed maintenance diet. The back fat thickness, plasma urea nitrogen before ovulation and progesterone concentrations, diameter of the largest follicle of the 2nd wave and growth rate of the largest follicle of the 3rd wave were higher in ewes that received overfeeding with soybean meal. The growth rate of the largest follicle of the 1st wave was higher in ewes that received overfeeding with corn gluten meal. Overfeeding with protein-rich feeds may increase the ovulation number and with soybean meal, it may be effective in increasing plasma progesterone concentration in ewes.

Objetivou-se avaliar o efeito do manejo para crescimento compensatório e da suplementação com ionóforo sobre o perfil metabólico e o crescimento da glândula mamária de novilhas leiteiras. Foram utilizadas 20 novilhas Pardo-Suíças puras, com peso inicial de 200 kg e 5 meses de idade. Os tratamentos foram arranjados em esquema fatorial 2 × 2 e os animais foram alocados aleatoriamente em cada uma das combinações. O fator 1 consistiu dos sistemas de alimentação (convencional e crescimento compensatório) e o fator 2, da utilização ou não de ionóforo (200 mg de monensina/animal/dia). Os animais do sistema convencional receberam alimentação ad libitum, enquanto os do sistema para crescimento compensatório foram submetidos a um manejo nutricional com dois períodos distintos: período de restrição energética (90 dias, P1) e período de realimentação (60 dias, P2). Novilhas submetidas ao sistema crescimento compensatório apresentaram maior concentração de nitrogênio ureico (N-ureico) plasmático e menor razão DNA:RNA no tecido mamário. Quando analisados dentro de período, os níveis de lipoproteínas de alta densidade (HDL) aumentaram no período de realimentação, enquanto os de N-ureico diminuíram. Além da alteração nos níveis de N-ureico, o balanço energético ao qual as novilhas em crescimento compensatório foram submetidas ocasionou aumento no teor dos ácidos graxos não-esterificados. Houve redução nos níveis de glicose sanguínea dos animais em crescimento compensatório no período de realimentação. A suplementação com ionóforo proporciona menor concentração de ácidos graxos não-esterificados durante o período de realimentação.

The objective of this trial was to compare the effect of compensatory growth regime on the metabolic profile and mammary gland development of dairy heifers. Twenty Brown-Swiss heifers averaging 200 kg of body weight and five months of age were used in a completely randomized design with a 2 × 2 factorial arrangement. The treatments were arranged in a factorial arrangement (2 × 2) and the animals were randomly allocated in each one of the combinations. The factor 1 consisted of the feeding regime (conventional and compensatory growth) and the factor 2, of the use or not of ionophore (200 mg of monensin/animal/day). The animals in the conventional regime received ad libitum feeding, while those in the compensatory growth regime were submitted to a nutritional management with two different periods: period of energy restriction (90 days) and realimentation period (60 days). Heifers submitted to the compensatory growth regime showed larger concentration of plasma urea nitrogen and lower DNA:RNA ratio in the mammary gland. When period was analyzed, the levels of high density lipoprotein (HDL) increased in the realimentation period, while the urea N decreased. In addition to the alteration in the levels of urea N, the energy balance to which the heifers in compensatory growth were submitted increased the non-esterified fatty acids. Blood glucose levels reduced in the animals in compensatory growth during the realimentation period. Supplementation with ionophore results in lower concentration of non-esterified fatty acids during the realimentation period.

This experiment aimed to determine the influence of diets with inclusion of protected fat and vitamin E on performance, yield and carcass characteristics of feedlot lambs with different weights. Thirty-two non-castrated Santa Ines lambs were fed diets with a ratio of 40% forage and 60% concentrate ad libitum, with presence or absence of protected fat and/or vitamin E, in a total of four diets. Two weights of early containment were also considered: between 20 and 25 kg and between 30 and 35 kg. All animals were slaughtered at 84 days of confinement. Animals fed diets without addition of protected fat, regardless of the use of vitamin E, had the highest intakes of dry matter, crude protein, neutral detergent fiber and ash, and decreased intake of ether extract. The variables investigated did not affect daily weight gain and total gain. Feed conversion was better for the lighter confined animals not fed protected fat. The heavier feedlot lambs fed diets with vitamin E showed higher cold carcass. The warm carcass for the lighter animals confined fed with vitamin E, and the heavier ones, fed with protected fat and vitamin E, showed the best yields of cold carcass. Objective measures of the carcass cold had the highest mean for heavier feedlot lambs. The addition of fat in the diet reduces the intake of dry matter and increases the ether extract. Although the inclusion of vitamin has no effect on intake of nutrients, it protects the carcasses from losses during cooling, and weight differences at containment directly reflect the measures of the carcasses.

To evaluate the effect of using urea in the diet on ovarian follicular dynamics and plasma urea and progesterone concentration, an experiment was carried out with 29 Alpine goats randomly distributed into four diets, each one containing 0%; 0.73%; 1.46% or 2.24% of urea on total dry matter. The follicular dynamics was monitored daily by ultrasonography. The estrous cycles were characterized by occurrence of two, three, four or five follicular waves. The emergence day of the first follicular wave in cycles with two waves, the length of the third wave and the maximum diameter of the largest follicle of the third wave in cycles with three waves presented a quadratic behavior according to the percentage of urea in the diets. In cycles with four waves, the urea intake did not influence the follicular dynamics. The interestrus and interovulatory periods and the luteal and follicular phases length did not differ among treatments. The plasma urea concentration did not differ among diets neither among collection weeks. Plasma progesterone concentration on the estrus day and on the 11th day after estrus presented quadratic behavior, and on the 15th day after estrus, it linearly reduced acording to the percentage of urea in the diets. The supply of urea in diets at levels up to 2.24% in dietary dry matter did not influence the dry matter intake and the urea plasma concentration. For goats, the emergence day and the length of the waves, the follicular diameter and the plasma progesterone concentration on the estrus day and in the latter stages of diestrus were altered when there was supply of urea in the diet.

Objetivou-se investigar os efeitos da ureia na produção, qualidade e estádio de desenvolvimento embrionário e status folicular ao início do tratamento superovulatório de animais alimentados com ureia na dieta. Dezoito cabras da raça Toggenburg foram distribuídas equitativamente para receberem dietas: sem ureia (controle, n=8) e 2,4% de ureia na matéria seca total da dieta (n=10) UMS. Os embriões foram recuperados entre o 7º o 8º dia após o estro pela técnica transcervical e classificados pela qualidade e pelo estádio de desenvolvimento. O status folicular foi determinado por ultrassonografia transretal no dia da aplicação da primeira dose de FSH. O número e a qualidade dos embriões não foram influenciados pela concentração de ureia na dieta. Embriões em estádio avançado de desenvolvimento foram recuperados do tratamento com 2,4% de ureia. A concentração de ureia testada (2,4%) diminui o número de folículos com menos de 5 mm de diâmetro, categoria que se correlaciona positivamente ao número de embriões coletados e ao número e à porcentagem de embriões excelentes e bons.

The effects of feeding urea on embryo production, quality and developmental stages and follicular status at the beginning of a superovulatory treatment of Toggenburg does fed urea diet were investigated in this study. Eighteen females were randomly allocated to receive diets with: no urea (control, n=8), and 2.4% urea dietary dry matter (n=10) UDM. The embryo recovery was performed at day 7 or 8 of estrus cycle by transcervical technique and classified according to quality and developmental stage. The follicular status was determined by transrectal ultrasonography at the first day of FSH injection. The number and quality of embryos were not affected by dietary urea concentration. Embryos from does treated with 2.4% UDM were recovered at advanced stage. Urea concentration (2.4%) decreases the number of follicles with less than 5 mm diameter. This follicle class is positively correlated to the number of recovered embryos and to the number and percentage of excellent and good embryos.

Este estudo foi realizado com o objetivo de avaliar a concentração plasmática de N-ureico, o número de ovulações e o diâmetro do folículo ovulatório de ovelhas da raça Santa Inês submetidas a sobrealimentação com fontes de proteína de diferentes degradabilidades ruminais. Quarenta e quatro ovelhas com o estro sincronizado receberam dietas isoproteicas, formuladas com farelo de soja (n=24) ou com glúten de milho e farelo de algodão (n=20) durante 28 dias antes da ovulação. Os animais foram distribuídos em delineamento de blocos, com os blocos formados por três faixas de escore de condição corporal. O ganho de peso vivo e de escore de condição corporal, o peso vivo e o escore de condição corporal no 28º dia do experimento, a concentração plasmática de N-ureico, o número de ovulações e o diâmetro do folículo ovulatório não diferiram entre as ovelhas submetidas à sobrealimentação com farelo de soja ou com glúten de milho e farelo de algodão. As ovelhas que receberam sobrealimentação com farelo de soja apresentaram maior concentração plasmática de N-ureico nos dias 7 e 14 e menor no dia 28 em comparação às que receberam sobrealimentação com glúten de milho e farelo de algodão (interação dieta vs dia). O fornecimento de uma dieta com menor teor de proteína degradável no rúmen não reduz concentração plasmática de N-ureico nem altera o número de ovulações e o diâmetro do folículo ovulatório.

This study aimed at evaluating plasma concentration of urea nitrogen, the number of ovulations and the diameter of ovulatory follicle of Santa Ines ewes submitted to flushing with sources of protein with different ruminal degradabilities. Forty-four estrus-synchronized ewes were fed isoprotein diets composed of soybean meal (n = 24) or corn gluten meal and cottonseed meal (n = 20) for 28 days before ovulation. Animals were distributed in a block design in which the blocks were formed by three score ranges of body condition score. Body weight and body condition score gains, body weight and body condition score on the 28th experimental day, urea nitrogen plasma concentration, number of ovulations and diameter of the ovulatory follicle did not differ among ewes submitted to flushing with soybean meal or with corn gluten and cottonseed meal. Ewes under soybean meal flushing showed higher urea nitrogen plasma concentration on days seven and 14 and lower concentration on the 28th day when compared to those fed corn gluten and cottonseed meal (day vs. diet interaction). The supply of one diet with lower content of ruminal degradable protein does not reduce urea nitrogen plasma concentration neither alters the number of ovulations and diameter of ovulatory follicle.

A manifestação do comportamento estral foi avaliada durante um estro induzido e o estro subseqüente, em 12 vacas da raça Guzerá, no inverno e no verão em dois anos consecutivos. A proporção de vacas que respondeu à sincronização de estros foi de 84,8%. Observou-se efeito de interação entre estação e ano sobre a duração do ciclo estral. O proestro foi maior no verão (57,69±4,72h) e no estro natural (74,23±4,41h), que no inverno (38,95±4,02h) e no estro induzido (22,40±4,36h). A duração do estro foi similar no inverno (11,48±0,70h) e no verão (13,40±0,82h), assim como entre as vacas com estro induzido (12,47±0,75h) e natural (12,41±0,76h). O número de montas recebidas durante o estro e o número de montas recebidas/hora em estro foram similares no inverno (29,17±2,86 e 2,59±0,22, respectivamente) e no verão (31,45±3,36 e 2,42±0,26, respectivamente), assim como entre o estro induzido (30,23±3,10 e 2,54±0,24, respectivamente) e o natural (30,40±3,14 e 2,47±0,24, respectivamente). A duração e a intensidade do estro não foram influenciadas pela sincronização ou pela estação do ano. O maior período de proestro no verão pode favorecer a identificação dos animais sexualmente ativos.

The estrus behavior was evaluated during an induced and natural subsequent estrus in twelve Guzera breed cows, in the winter and summer seasons in two consecutive years. The proportion of cows that responded to estrus synchronization was 84.8%. The effect of the interaction season x year of experiment on estrous cycle length was observed. Pro-estrus was longer in the summer (57.69±4.72h) and in the natural estrus (74.23±4.41h) than in the winter (38.95±4.02h) and in the induced estrus (22.40±4.36h). Estrus length was similar in the winter (11.48±0.70h) and in the summer seasons (13.40±0.82h) as well as among cows with induced (12.47±0.75h) and natural estrus (12.41±0.76h). The number of mounts accepted during estrus and the number of mounts accepted/ hour in estrus were similar in winter (29.17±2.86 and 2.59±0.22, respectively) and summer (31.45±3.36 and 2.42±0.26, respectively) as well as between induced (30.23±3.10 and 2.54±0.24, respectively) and natural estrus (30.40±3.14 and 2.47±0.24, respectively). The length and intensity of estrus were not influenced by synchronization or season of the year. Longer period of pro-estrus in summer may favor the identification of sexually active animals in this season.

This study investigated the functional capacity, the social, economic and nutritional status of the elderly in the area covered by the Family Health Program in the region of the Upper Jequitinhonha Valley. In terms of functional capacity, the elderly in general did not need help to bathe, do personal hygiene, dress,feed and move. As to nutrition, 33.3% were undernourished, 40.6% normal and 26.1% were obese. 64.0% lived with up to two minimum wages. There was a need for permanent monitoring of the susceptible age group, and focus on preventive measures, especially on nutritional status.

En este trabajo se analizaron la capacidad funcional, la situación socioeconómica y el estado nutricional de ancianos del área de alcance del Programa Salud de la Familia de un municipio del Valle del Alto Jequitinhonha, con miras a verificar la asociación entre estos tres aspectos. En cuanto a la capacidad funcional se observó que, en general, los ancianos no precisaban ayuda para su higiene personal, bañarse, vestirse, alimentarse y desplazarse; en relación al estado nutricional: 33,3% estaba desnutrido, 40,6% eutrófico y 26,1% obeso; la situación socioeconómica revela que 64,0% de los ancianos vivía con hasta dos sueldos mínimos. Quedó constatada la necesidad de controlar permanentemente a este grupo etario con miras a adoptar medidas preventivas, sobre todo en lo referente al estado nutricional.

Neste estudo, investigaram-se a capacidade funcional, a situação socioeconômica e o estado nutricional de idosos da área de cobertura do Programa Saúde da Família (PSF) de um município do Alto Jequitinhonha, buscando verificar a associação entre eles. Quanto à capacidade funcional, em geral os idosos não necessitavam de ajuda para tomar banho, realizar higiene pessoal, vestir-se, alimentar-se e locomover-se. Quanto ao estado nutricional, 33,3% eram desnutridos, 40,6% eutróficos e 26,1% obesos. Constatou-se que 64,0% dos idosos viviam com até dois salários mínimos. Evidenciou-se a necessidade de monitoramento permanente do grupo etário, visando a medidas preventivas, principalmente em relação ao estado nutricional.

Foram utilizadas 25 fêmeas, distribuídas de acordo com o grau de sangue Holandês x Zebu nos grupos: I = 1/2 Holandês x Zebu; II = 3/4 Holandês x Zebu; III= 15/16 Holandês x Zebu; IV= Holandês--PB<FONT FACE=Symbol>¾</FONT>PC; e V= 7/8 Holandês x Zebu. Após o segundo estro natural pós-parto, esses animais foram monitorados por exames ultra-sonográficos diários por dois ciclos estrais consecutivos, para verificar a atividade ovariana quanto à dinâmica folicular e à atividade do corpo lúteo. O período interovulatório médio foi de 22,08±2,46 dias, sendo de 21,76±3,33 e 21,94±2,90 dias no primeiro e no segundo ciclo estral, respectivamente, não havendo diferença entre os grupos estudados. Observou-se o crescimento de uma (6%), duas (78%) e três (16%) ondas foliculares durante o ciclo estral, com a predominância de duas ondas foliculares. O período interovulatório dos ciclos com três ondas mostrou-se mais longo (25,33±4,37 dias), em comparação com uma (16,0±3,6 dias) e duas (21,83±1,77 dias) ondas foliculares. A duração das ondas foliculares para ciclos estrais com três ondas de crescimento folicular foi de 11,0±3,69; 7,17±1,60; e 8,5±1,52 dias na 1ª, 2ª e 3ª ondas, respectivamente, e de 11,15±1,65 e 12,07±2,32 dias nos ciclos estrais com duas ondas foliculares. Os dias de maior concentração plasmática de progesterona no 1º e 2º ciclos estrais foram, respectivamente, de 13,6±3,0 (7,29±4,3 ng/mL) e 11,8±3,4 (5,6±2,0 ng/mL) dias, não se mostrando diferentes entre os grupamentos genéticos e ciclos estrais estudados. Pelas análises dos dados, pode-se concluir que os diferentes grupamentos genéticos apresentaram o mesmo comportamento na dinâmica folicular e que as concentrações de progesterona, embora diferentes em números absolutos entre os grupamentos, mostraram-se indicativas de atividade luteal normal.

To verify the ovarian activity in respect to follicular dynamics and corpus luteum activity, 25 cows distributed in five experimental groups according to the crossbreeding level as: group 1: 1/2 Holstein x Zebu, group 2: 3/4 Holstein x Zebu, group 3: 15/16 Holstein x Zebu, group 4: crossbreed pure Holstein and group 5: 7/8 Holstein x Zebu, were daily monitored by ultrasonography examination during two estrous cycle after the second postpartum cycle. The average in days for the interovulatory period were respectively, for the first and second cycles: 21.76±3.33 and 21.94 ± 2.90. There was no difference between these values. The average for the interovulatory period between cycles was 22,08±2,46 days. In this experiment, the development of one (16%), two (78%) and three (16%) follicular waves was verified, with predominance of two follicular waves. The interovulatory period in three waves cycles (25.33±4.36 days) was longer when compared to one (16.0±3.6 days) and two (21.69±1.97 days) waves cycles. The follicular waves average length were: 11.0±3.69, 7.17±1.60 and 8.5±1.52 days, respectively, for the first, second and third follicular waves. In estrous cycles where only two waves occurred, the waves average length were: 11.15±1.65 and 12.07±2.82 days. The highest progesterone concentrations in the first and second estrous cycle were, respectively, in the 13.6±3.0 (7.29±4.3 ng/mL) and 11.8±3.4 (5.6±2.0 ng/mL) days and were not different among experimental groups and estrous cycle. After the analyses, it was concluded that the different experimental groups presented the same follicular dynamics behavior, and despite the differences in absolute numbers in progesterone concentration among the groups, they were indicative of normal luteal activity.