RESUMO
The effect of low-density diets on bird performance, egg composition, and embryonic development was studied with 2,100 female and 210 male Cobb broiler breeders from 25 to 60 wk of age. The experiment included 5 treatments. These included a control group with a normal density diet (ND, 2,800 kcal of AME/kg). Treatments 2 (LD11) and 3 (LD21) had a 11 and 21% lower nutrient density. Treatment 4 (LD11(OP)) had a 11% less dense diet, which was obtained by inclusion of other feed ingredients. In these 4 treatments similar diets were given during the rearing and the laying period. Treatment 5 combined LD12 in the rearing period and ND diets during the laying period (LD12-ND). Egg composition and embryonic development were measured in eggs of ND and LD21 birds at 29 and 41 wk of age. During the laying period from wk 25 to 60, live weights did not differ among treatments, except that birds fed LD11(OP) had lower live weights. A significantly higher rate of lay was provided by LD11 compared with ND. Egg weights were significantly higher when low-density diets were fed, particularly in LD11(OP). Percentage of fertile eggs did not differ among treatments. Compared with the other treatments, LD11(OP) provided a significantly lower hatchability. We found that LD21 resulted in a better development of the area vitellina externa and heart and embryo weight at 29 wk of age. It was concluded that this was related to a higher egg weight and egg white proportion. This suggests that the amount of egg white in eggs of hens fed ND was limiting for embryonic development, particularly in eggs of young broiler breeders.
Assuntos
Embrião de Galinha/efeitos dos fármacos , Embrião de Galinha/embriologia , Galinhas/fisiologia , Dieta/veterinária , Oviposição/efeitos dos fármacos , Oviposição/fisiologia , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Feminino , Fertilidade/efeitos dos fármacos , Masculino , Óvulo/química , Óvulo/efeitos dos fármacos , Óvulo/fisiologiaRESUMO
High yielding dairy cows experience a negative energy balance (NEB) shortly after parturition, which is accompanied by high concentrations of non-esterified fatty acids (NEFA) in blood up to approximately 3 weeks post partum. We hypothesized that the elevated plasma NEFA concentration causes lower fertility by exerting negative effects on granulosa cells and oocytes in the ovary, leading to less viable embryos and insufficient corpora lutea. In two series of experiments, we studied the effects of a realistic NEFA (C18:1) concentration on both the proliferation and the progesterone production of follicular granulosa cells in vitro (part I) and on maturation, fertilization and developmental potential of oocytes (part II). For part I, granulosa cells were added to 4 groups of dishes with four different media and cultured for nine consecutive days. After a preculture period of 42h, the presence of NEFA had a negative effect on the proliferation of granulosa cells. No effect of NEFA on the amount of progesterone production per cell was observed. For part II, a total of 1804 cumulus-oocyte-complexes were collected from slaughterhouse ovaries. Using a subgroup of 690 COC, maturation medium with NEFA caused a delay in maturation. Using another 1114 COC, fertilization, cleavage, and embryonic development after maturation in presence of NEFA were significantly reduced. We concluded that the presence of NEFA in follicular fluid and blood of post partum cows may reduce fertility due to hampered embryonic development and subnormal CL function.
Assuntos
Bovinos/fisiologia , Ácidos Graxos não Esterificados/farmacologia , Células da Granulosa/efeitos dos fármacos , Oócitos/efeitos dos fármacos , Animais , Divisão Celular/efeitos dos fármacos , Células Cultivadas , Feminino , Fertilização in vitro , Células da Granulosa/citologia , Células da Granulosa/metabolismo , Oócitos/crescimento & desenvolvimento , Oócitos/fisiologia , Progesterona/biossínteseRESUMO
Paratuberculosis is a chronic and progressive disease of the intestine in ruminants caused by Mycobacterium avium subsp. paratuberculosis (Map). The bacterium is transmitted to young animals, becomes manifest in adulthood and leads to economic losses. The aim of this study is to investigate if cows shedding Map possess oocytes and embryos that are carriers of the bacterium. New genetical material can enter the dairy farm using embryo transfer but the question as to whether this technique is safe with respect to transmission of paratuberculosis has yet to be addressed. We selected and bought 16 cows, all proven to be moderate shedders of the bacterium in the faeces immediately prior to the experiment but none were clinically sick. One sample of uterine content was collected from each animal by flushing the uterus on the day of heat and five samples of homogenised uterine tissue were collected on the eighth day of the same cycle by biopsy. In addition, 217 cumulus-oocyte complexes (COCs), ranging from 3 to 35 COCs per animal, were collected using ultrasound guided transvaginal puncture of the ovarian follicles (OPU). On the seventh day of the subsequent cycle 31 embryos were obtained using the classic technique of super ovulation induction, artificial insemination (AI), followed by flushing of the uterus. These embryos have been washed and trypsinised. Fourteen of the 16 cows were treated again for super ovulation in the subsequent cycle and 19 foetuses were collected by opening of the uterus after euthanasia on Days 35-49 of the cycle. All samples were cultured for presence of Map and checked every 2 months during 1 year for bacterial growth. None of the samples showed growth of Map after 12 months of culture. Pathological examination of the cows revealed different degrees of severity of pathological alterations of the intestinal tract and mesenteric lymph nodes. However, the results suggest that neither in vivo embryo's nor oocytes are carriers of the bacteria and do not form an extra risk at transfer. However, due to the limited size of the experiment (sample size of 16 cows), a certain margin for error remains.
Assuntos
Doenças dos Bovinos/transmissão , Embrião de Mamíferos/microbiologia , Transmissão Vertical de Doenças Infecciosas/veterinária , Oócitos/microbiologia , Paratuberculose/transmissão , Animais , Bovinos , Doenças dos Bovinos/microbiologia , Fezes/microbiologia , Feminino , Intestinos/microbiologia , Mycobacterium avium subsp. paratuberculosis/isolamento & purificação , Mycobacterium avium subsp. paratuberculosis/patogenicidade , Paratuberculose/microbiologia , GravidezRESUMO
It is known from epidemiological studies that negative energy balance in early lactating dairy cows is related to a depression in reproductive performance. Elevated plasma concentrations of non-esterified fatty acids (NEFA) are a typical metabolic characteristic of these animals and are proposed as the possible link. The suggestion is that NEFA might have a direct effect on the ovary, by affecting development of the oocyte or the granulosa cells. However, no data is available concerning the relationship between the concentration of NEFA in follicular fluid and plasma. Therefore, a cross-over study with 10 heifers around 15 months of age was conducted to analyze this relationship and examine the suggested effects of the negative energy balance on follicular growth. Investigation of these effects was performed on fasted heifers. The experimental treatment consisted of feeding hay with a subsequent period of fasting, to induce elevated plasma NEFA concentrations. Sampling of follicular fluid was performed using transvaginal aspiration of follicles, which were standardized using a synchronization protocol. In addition, concentrations of glucose, insulin, NEFA, and estradiol were measured in plasma. Follicular estradiol and progesterone concentrations were also measured to assess the quality of the dominant follicle. Fasting resulted in significantly lower plasma glucose (P=0.0006) and plasma insulin (P<0.0001) concentrations, higher plasma estradiol (P=0.008) and higher NEFA (P<0.001) concentrations, and smaller follicles (P=0.04) with lower estradiol:progesterone (E/P) ratios (P=0.05). Concentrations of NEFA in follicular fluid and plasma were closely related. Given this close relationship, we concluded that the presence of high plasma NEFA concentrations might link energy metabolism in early lactation with fertility.
Assuntos
Bovinos/fisiologia , Metabolismo Energético/fisiologia , Jejum/fisiologia , Ácidos Graxos não Esterificados/análise , Líquido Folicular/química , Folículo Ovariano/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Glicemia/análise , Bovinos/metabolismo , Estudos Cross-Over , Estradiol/análise , Estradiol/sangue , Ácidos Graxos não Esterificados/sangue , Feminino , Fertilidade/fisiologia , Insulina/sangue , Modelos Animais , Progesterona/análiseRESUMO
In current in vitro production (IVP) systems, oocytes lack in vivo dominant and preovulatory follicular development, which may compromise pregnancy and viability of calves born. When an oocyte sets off in vivo on the road toward fertilization, it contains numerous transcripts and proteins necessary to survive the first few cell cycles of embryonic development. It is not yet known during which period of development the oocyte builds up the store, possibly primarily during the major growth phase of the oocyte, which is completed at the time a follicle reaches the size of 3 mm. Here, we investigated to what extent the later phases of follicular development, such as prematuration in the dominant follicle before the LH surge and ensuing final maturation in the preovulatory follicle, contribute to oocyte competence and development into viable biastocysts. Recent studies on in vivo vs in vitro oocyte maturation employed oocytes from an identical preovulatory development by applying ovum pick-up (OPU) twice (before and 24 h after the LH surge) in each cow treated for superovulation with a controlled LH surge. The embryo recovery rates at Day 7 of IVC after IVF were similar: 44% (97/219) for in vivo- vs 41% (87/213) for in vitro-matured oocytes, which shows that the natural environment during final maturation is not essential for the mere in vitro development of the prematured oocyte beyond the 8- to 16-cell stage. However, in vivo maturation appeared to contribute to the oocyte's quality in a more subtle way, as indicated by a significant increase in the proportion of expanded blastocysts and a more physiological degree of chromosome aberrations of the embryos. In blastocysts derived from in vivo-matured oocytes, 21% of the embryos were mixoploid vs 50% from in vitro-matured oocytes, concomitant with a higher number of cells (96 vs 54 per normal blastocyst). The expression pattern of a set of six developmentally important genes was, however, not significantly altered in blastocysts derived from in vivo-matured oocytes. Certain deviations were observed compared with the levels of entirely in vivo-developed control blastocysts, which suggests that the beneficial effects of in vivo maturation are possibly exerted at initial stages of embryonic development. Prematuration in vivo, occurring in a dominant follicle developing from about 8 mm into the preovulatory follicle, is accompanied by changes in protein synthesis of the cumulus oocyte complex (COC). Presumably, the differentially expressed proteins are involved in equipping the oocyte with further developmental competence. Although we have unraveled some important biochemical and cellular biological features of the oocyte, further research on in vivo processes is essential to improve in vitro embryo production in practice.
Assuntos
Blastocisto/citologia , Bovinos/embriologia , Embrião de Mamíferos/citologia , Oócitos/citologia , Animais , Bovinos/fisiologia , Ciclo Celular , Células Cultivadas , Desenvolvimento Embrionário e Fetal , Feminino , Técnicas In Vitro , Hormônio Luteinizante/metabolismo , Hormônio Luteinizante/farmacologia , Folículo Ovariano/citologia , Folículo Ovariano/fisiologia , SuperovulaçãoRESUMO
A 2 year-old cow with abnormal behaviour was observed during a farm visit. Rectal palpation of the cow revealed the presence of a mass of at least 12 cm in diameter. After further examination, it appeared that 'ovarian tumour' was the most likely differential diagnosis. In order to confirm this diagnosis, blood samples were drawn and analysed for plasma progesterone and plasma oestradiol-17 beta concentrations. Also, the gross pathology and histology of the mass were evaluated. The combination of the clinical presentation of the cow, the hormone concentrations, and the histological appearance of the mass confirmed the diagnosis ovarian tumour. The tumour was classified as granulosa-theca cell tumour.
Assuntos
Doenças dos Bovinos/diagnóstico , Tumor de Células da Granulosa/veterinária , Neoplasias Ovarianas/veterinária , Tumor da Célula Tecal/veterinária , Animais , Bovinos , Doenças dos Bovinos/sangue , Diagnóstico Diferencial , Estradiol/sangue , Feminino , Tumor de Células da Granulosa/sangue , Tumor de Células da Granulosa/diagnóstico , Neoplasias Ovarianas/sangue , Neoplasias Ovarianas/diagnóstico , Progesterona/sangue , Tumor da Célula Tecal/sangue , Tumor da Célula Tecal/diagnósticoRESUMO
This study was designed to elucidate associations between energy metabolism and LH pulsatility characteristics in early lactation, and days to first ovulation, in order to explain the relationship between energy balance and fertility observed in epidemiological studies. To this end, 10 multiparous HF cows were monitored during lactation, after the application of two different feeding strategies during the dry period. Days to first ovulation was assessed using blood progesterone measurements and LH pulsatility was measured in 8-h windows in the third week postpartum. The association between depth of negative energy balance and days to ovulation was confirmed. However, this study does not support the idea that LH pulsatility characteristics in early lactation are predictive for the interval between parturition and first ovulation.
Assuntos
Bovinos/metabolismo , Lactação/metabolismo , Hormônio Luteinizante/sangue , Ovulação , Ácido 3-Hidroxibutírico/sangue , Animais , Glicemia , Metabolismo Energético , Feminino , Insulina/sangue , Período Pós-Parto , GravidezRESUMO
The aim of this study was to analyze the effect of robotic milking (RM) on fertility and somatic cell counts (SCC) among dairy herds participating in the national Dutch milk recording system. It was hypothesized that RM, and a higher milking frequency in general, would have negative effects on fertility, due to expected and supposed deeper negative energy balance (NEB). Herds increasing milking frequency from two to three times daily consistently had increased production. Milk production during RM was intermediate between the amounts obtained by milking twice versus three times a day. Milking three times a day and the associated higher production had no significant effect on reproductive measures such as nonreturn rate at 56 d post insemination (NR56) or days to first service. Although RM did not affect NR56, use of the robot was associated with an increase in days to first service. An increase in milking frequency from two to three times daily did not affect SCC, but SCC were significantly increased after milking with the robot. Robotic milking has a significant positive effect on production and no negative effect on fertility as measured by NR56. The effect of RM in increasing days to first service appears due to reasons other than increased production and a more NEB. Increased SCC during RM is potentially of concern. From the data available, the relationship of RM to clinical mastitis could not be determined but this aspect needs further attention.
Assuntos
Bovinos/fisiologia , Contagem de Células , Indústria de Laticínios/instrumentação , Fertilidade , Leite/citologia , Robótica , Animais , Indústria de Laticínios/métodos , Feminino , LactaçãoRESUMO
The present study aimed to test the generally accepted view that a follicular wave starts with follicles newly recruited from the population smaller than 3 mm, which later compete for dominance. According to this view, subordinate follicles are expected to be too atretic to join the next follicular wave. Ten cows were ovariectomized shortly prior to the LH surge, thus around the start of the first follicular wave of the cycle. Per cow, on average, 14.4 follicles of >/=3 mm were dissected. Follicular health was determined on the basis of four parameters: 1) judgment of the degree of atresia by stereomicroscope, 2) incidence of apoptotic nuclei among the granulosa cells, 3) estradiol and progesterone concentrations, and 4) insulin-like growth factor-I (IGF-I) binding proteins (IGFBPs)-2, -4, and -5 concentrations in the follicular fluid. In addition to the preovulatory follicle, 3.1 other follicles, mainly sized 3-4.5 mm, were found to be healthy based on the proportion of apoptotic nuclei, and concentrations of estradiol/progesterone, and IGFBPs. The ability of these follicles to respond with growth on the preovulatory and periovulatory FSH surges was supported by a comparison to the follicular population of four cows 31-68 h after the LH surge. The present results point to an alteration of the view on the follicular wave. The larger follicles during the first days of the follicular wave are, in general, derived from follicles that also joined the previous wave. A portion of these growing follicles are estradiol active and compete for dominance. Other growing follicles lack estradiol production and are probably derived from rather atretic follicles. The first newly recruited follicles do not reach the size of 3 mm before 31 h after the preovulatory FSH surge. At that time, the larger follicles are already competing for dominance.