Fatores nutricionais associados à reprodução da fêmea bovina

Sartori, Roberto; Guardieiro, M. M.

doi:10.1590/s1516-35982010001300047

Cited by 25 publications

(15 citation statements)

References 100 publications

(85 reference statements)

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“…Após o início da estação de monta, houve aumento de peso das vacas em todos os tratamentos, mesmo sob condições de disponibilidade e qualidade inferior de forragem. Uma possível explicação para isso é que, durante esse período, o pico de produção de leite se estabelece semanas antes do pico de ingestão de matéria seca, e a energia utilizada para a manutenção e a produção de leite é maior do que a obtida com a alimentação (Sartori & Guardieiro, 2010).…”

Section: Resultsunclassified

Desempenho de vacas de corte Purunã submetidas a diferentes manejos de amamentação

Moura

Kuss

Moletta

et al. 2014

Pesq. agropec. bras.

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Resumo -O objetivo deste trabalho foi avaliar o desempenho ponderal e reprodutivo de vacas de corte submetidas a diferentes manejos de amamentação. Durante a estação de monta, de 85 dias, foram avaliadas 161 vacas de corte da raça Purunã, de acordo com os seguintes manejos de amamentação: desmame precoce, vacas separadas dos seus bezerros aos 75 dias pós-parto; amamentação controlada, vacas separadas de seus bezerros aos 75 dias de idade, mas colocadas para amamentar uma vez ao dia durante a estação de monta; e desmame convencional, vacas mantidas com seus bezerros ao pé até o final da estação de monta, aos 160 dias de idade dos bezerros, em média. As taxas de prenhez não foram significativamente afetadas pelos manejos de amamentação, tendo sido de 97% no desmame precoce, de 96% na amamentação controlada e de 90% no desmame convencional. No entanto, o desmame precoce resultou em menor eficiência reprodutiva (28,26 kg), quando comparado à amamentação controlada (35,09 kg) e ao desmame convencional (35,34 kg). Vacas de corte mantidas em boas condições corporais ao parto e ao início da estação de monta apresentam alta taxa de fertilidade, independentemente do manejo de amamentação dos bezerros.Termos para indexação: amamentação controlada, anestro pós-parto, desmame precoce, eficiência reprodutiva, intervalo entre partos, taxa de fertilidade. Performance of Purunã beef cows subjected to different nursing managementsAbstract -The objective of this work was to evaluate the weight and reproductive performance of beef cows subjected to different nursing managements. During the breeding season of 85 days, 161 beef cows of the Purunã breed were evaluated, according to the following feeding managements: early weaning, cows separated from their calves at 75 days postpartum; controlled nursing, cows separated from their calves at 75 days of age, but taken to nurse once a day during the breeding season; and conventional weaning, cows kept with their calves until the end of the breeding season, at 160 days of age of calves, in average. Fertility rates were not significantly affected by weaning managements, being 97% for early weaning, 96% for controlled nursing, and 90% for conventional weaning. However, early weaning resulted in lower reproductive efficiency (28.26 kg), when compared to controlled nursing (35.09 kg) and conventional weaning (35.34 kg). Beef cows maintained in good body conditions at birth and at the beginning of the breeding season have a high fertility rate, regardless of calf-feeding management.

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Section: Resultsunclassified

Desempenho de vacas de corte Purunã submetidas a diferentes manejos de amamentação

Moura

Kuss

Moletta

et al. 2014

Pesq. agropec. bras.

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“…However, in vitro embryo production from ovaries obtained from slaughterhouses is dependent upon the forage supply, which may be influenced by the effects of seasonality on forage production. (Sartori and Guardieiro, 2010).…”

Section: Discussionmentioning

confidence: 99%

Effect of seasonality on the quality of bovine oocytes selected by the brilliant cresyl blue method

Maia

Waltero

Marín³

et al. 2017

Rev Colomb Cienc Pecu

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Background: The brilliant cresyl blue (BCB) staining is a non-invasive test to select the best-suited oocytes for embryonic development. This makes it a useful tool to select best-quality oocytes at the times of the year when there is forage restriction. Objective: To evaluate the effect of seasonality on the nuclear maturation and quality of oocytes selected by the BCB test. Methods: The cumulus-oophorus complexes (COCs) were obtained in summer and winter of 2010 and 2011. Selected COCs were maintained for 90 min at 38.5 °C in a CO 2 incubator, in TCM 199 medium containing 10% fetal bovine serum and antibiotics, and supplemented with 26 µM brilliant cresyl blue. Afterwards, they were divided according to the ooplasm staining (BCB + -blue; BCB − -unstained). Subsequently, COCs were matured for 22 h. Nuclear maturation was evaluated at 22 h of culture. Results: The proportion of BCB − oocytes was higher in the winter of 2010, but there was no increase in this group in the winter of 2011. The percentage of oocytes that reached metaphase II was higher in control and BCB + groups in relation to oocytes from BCB − group. Conclusion: The season of the year influences the percentage of oocytes best suited for embryonic production in situations in which

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“…Although fundamental cattle physiology and its relation to nutrition are well known, there is not sufficient quantitative information about how management affects nutrition and reproduction, especially under natural grasslands conditions. In particular, few studies have been done to evaluate the relative effects of stocking rate and other nutritional management factors on pregnancy rates at a regional level (Gottschall & Lobato 1996; Simeone & Lobato 1996; Quadros & Lobato 1996; Fagundes, Lobato & Schenkel 2003; Pötter et al 2010; Sartori & Guardieiro 2010). The lack of single studies with regional scope is understandable because such studies with livestock are logistically complex and extremely expensive.…”

Section: Introductionmentioning

confidence: 99%

Direct and indirect nutritional factors that determine reproductive performance of heifer and primiparous cows

Eloy

Bremm

Lobato

et al. 2020

Preprint

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23Pregnancy rate is a major determinant of population dynamics of wild ungulates 24 and of productivity of livestock systems. Allocation of feeding resources, including 25 stocking rates, prior to and during the breeding season is a crucial determinant of this vital 26 rate. Thus, quantification of effects and interaction among multiple factors that affect 27 pregnancy rate is essential for management and conservation of pasture-based systems. 28 Pregnancy rate of 2982 heifers and primiparous cows was studied as a function of animal 29 category, average daily gain during the breeding season, stocking rate, pasture type and 30 body weight at the beginning of the breeding season. Data were obtained from 43 31 experiments conducted in commercial ranches and research stations in the Pampas region 32 between 1976 and 2015. Stocking rate ranged from 200 to 464 kg live weight/ha, which 33 brackets values for most of the grazinglands in similar regions. Age at breeding was 14-34 36 months (24.6 ± 7.5 months); initial breeding weights were 129-506 kg and 194-570 35 kg for heifers and primiparous cows. Pregnancy rate was modeled with an apriori set of 36 explanatory variables where proximate variables (breed, body weight at start of breeding, 37 weight gain during breeding and category) were included first and subsequently modeled 38 as functions of other variables (pasture type, supplementation and stocking rate). This 39 modeling approach allowed detection of direct and indirect effects (through nutrition and 40 body weight) of factors that affect pregnancy rate. Taurine (Bos taurus breeds, N = 1058) 41 had higher pregnancy rate than B. Taurus x B. indicus crossbreed (N = 1924) females.42Pregnancy rate of heifers and primiparous cows grazing in natural grasslands decreased 43 with increasing stocking rate, but no effect of stocking rate was detected in cultivated and 44 improved pastures. Pregnancy rate increased with increasing average daily gain during 45 the breeding season. Use of cultivated or improved natural pastures promotes higher 3 46 pregnancy rate, as well as allows higher in stocking rate at the regional level. Body weight 47 at the start of the breeding season is the primary determinant of pregnancy rates in heifer 48 and primiparous cows. 49 50 4 70changes in economic and technological factors that affect productivity (IBGE 2020). Low 71 pregnancy rates prevent full development of the livestock sector in many regions of the 72 world, and it may be associated with poor pasture management, overstocking and lack of 73 differential nutritional management for animal categories with different requirements. 74Stocking rate is considered the most important decision in grazing management because 75 it affects the forage base, herbage allowance, intake and animal performance 76 (Sollenberger, Agouridis, Vanzant, Franzluebbers & Owens 2012). Nutritional limitation 77 during periods of high requirement can compromise development and delay puberty of 78 heifers, as well as inhibit ovulation of cows (Rocha & Lobat...

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Fatores nutricionais associados à reprodução da fêmea bovina

Cited by 25 publications

References 100 publications

Desempenho de vacas de corte Purunã submetidas a diferentes manejos de amamentação

Desempenho de vacas de corte Purunã submetidas a diferentes manejos de amamentação

Effect of seasonality on the quality of bovine oocytes selected by the brilliant cresyl blue method

Direct and indirect nutritional factors that determine reproductive performance of heifer and primiparous cows

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