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The development of female gametes production (gametogenesis) occurs in an interesting way, as its process depends of many combined factors. This review will approach these morpho function mechanisms of the ovary and the folliculogenesis, correlating the function of Insulin-Like Growth Factors (IGFs), which will influence in the production of steroids hormones, in the maintenance follicular maturation, and still elucidate how the diet assists better in these phases. Besides that, with the new researches in animal reproduction, it is important emphasize the role and assists of Insulin-Like Growth Factors during this physiologic process, showing all its potential for a more efficient follicular dynamics in any species.

The purpose of this paper was to investigate the effect of the season of the year on testicular morphology, fresh and frozen/thawed semen quality from Pantaneiro bulls bred in Brasilia, DF. Six bulls were submitted, once a month for one year, to evaluation of testicular measurements, semen collection using an artificial vagina and cryopreserved with medium containing Tris-based, egg yolk and glycerol. The testicular length and volume were greater (P < 0.05) in June (11.1±0.8 cm; 652.7±138.0 cm3), July (11.0±0.9 cm; 616.4±156.2 cm3), and September (11.8±0.8 cm; 692.4±141.3 cm3) than October (9.4±1.2 cm; 498.5±154.3 cm3) and November (10.3±1.1 cm; 560.0±111.8 cm3). The sperm concentration was greater (P 0.05). In conclusion, Pantaneiro bulls, bred in the Midwest region of Brazil, can be used in natural mating programs in all seasons. Aiming to improve the Brazilian Animal Germplasm Bank with a higher number of samples collected, we suggest that the freezing of the semen is done between June and August, although there will be no losses of semen quality at any time. Keywords: bovine; conservation; cryopreservation; reproduction; seasonality.

The purpose of this paper was to investigate the effect o f t he s eason o f t he y ear o n testicular morphology, fresh and frozen/thawed semen quality from Pantaneiro bulls bred in Brasilia, DF. Six bulls were submitted, once a month for one year, to evaluation of testicular measurements, semen collection using an artificial v agina a nd c ryopreserved w ith m edium c ontaining Tris-based, egg yolk and glycerol. The testicular length and volume were greater (P < 0.05) in June (11.1±0.8 cm; 652.7±138.0 cm3), July (11.0±0.9 cm; 616.4±156.2 cm3), and September (11.8±0.8 cm; 692.4±141.3 cm3) than October (9.4±1.2 cm; 498.5±154.3 cm3) and November (10.3±1.1 cm; 560.0±111.8 cm3). The sperm concentration was greater (P 0.05). In conclusion, Pantaneiro bulls, bred in the Midwest region of Brazil, can be used in natural mating programs in all seasons. Aiming to improve the Brazilian Animal Germplasm Bank with a higher number of samples collected, we suggest that the freezing of the semen is done between June and August, although there will be no losses of semen quality at any time.

The objective of this study was to use morphometric and ultrasound evaluations to estimate the growth curve of the Pantaneiro cattle breed, raised in its natural habitat, aiming at the re-insertion of this breed in production systems. One hundred and three females, aging from months to 11 years, and raised on native pastures, were evaluated. The animals belonged to the Conservation Nucleus of Embrapa Pantanal, located in the Pantanal of Mato Grosso do Sul (Brazil). Weight, thoracic perimeter (TP), body length (BL), rump height (RH), height at withers (HW), hip height (HH), depth (DP), distance between the ilia (DI) (cm) and rib-eye area (REA) were measured. To relate the measurements with the age of the animals, the univariate regression model was used, assigning the variable response to gamma distribution. The Pearson correlation between variables was also estimated. The inflection point of the growth curve was 37 months for HH; between 38 and 39 months for TP and HW; between 40 and 41 months for DI, HH and DP; and 45 months for BL. The REA results could not fit in a statistical model. The majority of the variables presented a correlation above 60% among themselves, except for REA × Age, of 15.81%; REA × HW, of 34.44%; HH × Age, of 46.19; HH × DI, of 58.07%; REA × HH, of 24.57%; and REA × TP, of 39.9%. The cows showed maturity age at 40 months, which may have occurred because they were raised in natural farming conditions. In Pantaneiro cows reared in extensive systems only on natural pastures, the use of ultrasound is not effective to estimate the curve of muscular development, perhaps because this breed was not selected for weight gain.

Inadequate ingestion of nutrients in quality and quantities is common cause of infertility in ewe and mechanisms involved between nutrition and reproduction is changeable. The aim of this work was to evaluate the energy or protein restriction during lactation in ewe on return of reproductive cyclic activity. Twenty one females in post-partum was divided randomly in 3 treatments: control treatment (CT, diet supply the requirements for maintenance and lactation), caloric restriction (CRT, supplied ½ of the diet of the CT), protein restriction (PRT, supplied 1/3 of the protein of the CT). Trans-rectal ultrasound was performed to ovary evaluation weekly and the body weight were measured biweekly. Effect of treatment on number (PA ingestão inadequada de nutrientes em qualidade e quantidade influencia a fertilidade das ovelhas, sendo variados os mecanismos envolvidos na inter-relação nutrição e reprodução. Objetivou-se avaliar os efeitos da restrição calórica ou protéica em ovelhas, durante a fase de lactação, sobre o desenvolvimento folicular e retorno à atividade cíclica pós-parto. Foram utilizadas 21 ovelhas SRD, recém-paridas, divididas aleatoriamente em três tratamentos: tratamento controle (TC - dieta que atendia aos requerimentos de mantença e lactação), restrição calórica (TRC - fornecia 1/2 da dieta do TC), restrição protéica (TRP - fornecia 1/3 da proteína do TC). Semanalmente, os animais foram submetidos à ultrassonografia transretal para avaliação ovariana, e quinzenalmente pesados. O número de folículos (P