Sistemas de Alimentação Pós-Desmama de Bezerras de Corte para Acasalamento com 14/15 Meses de Idade

Rocha, Marta Gomes da; Lobato, José Fernando Piva

doi:10.1590/s1516-35982002000700025

Cited by 23 publications

(25 citation statements)

References 15 publications

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“…Other authors, working with heifers of the same age and fed similar diets, obtained lower pregnancy rates than the present study; however, the body weights of their heifers at the start of breeding season were lower, also due to lower weaning weights (Rocha and Lobato, 2002;Pilau et al, 2005;Azambuja et al, 2008;Pilau and Lobato, 2009).…”

Section: Discussioncontrasting

confidence: 47%

“…It has been previously shown that pregnant heifers present better growth rates and body condition scores than non-pregnant heifers (Semmellman et al, 2001;Rocha and Lobato, 2002). These responses allow the selection of heifers better adapted to each production system.…”

Section: Discussionmentioning

confidence: 95%

“…Higher body weight gain in pregnant heifers compared with non-pregnant heifers is reported in the literature (Rocha and Lobato, 2002); Azambuja et al, 2008). Patterson et al (1992) emphasized the importance of pre-weaning weight gain for puberty onset, considering the harmful effects of poor nutrition on puberty described by Short and Bellows (1971).…”

Section: Discussionmentioning

confidence: 99%

“…High pre-weaning weight gain and, consequently, high weaning weight, are essential to obtain good pregnancy rates when heifers are mated at 14-15 months of age (Rocha and Lobato, 2002;Vaz et al, 2012), with influences on the reproduction performance when they are primiparous cows (Scaglia, 1997). Quadros and Lobato (1997) showed that calves born in the beginning of spring (September) from cows grazing on natural pastures at low stocking rates and, therefore, with high pasture allowance and better quality, are heavier at weaning.…”

Section: Discussionmentioning

confidence: 99%

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Development and reproductive performance of Hereford heifers of different frame sizes up to mating at 14-15 months of age

et al. 2018

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-Body development and reproductive performance of a hundred forty-two 14 to 15-month-old heifers, classified at weaning according to frame size as small, medium, and large, were evaluated. The parameters evaluated were: body weight, hip height, body condition score, weight gain, ovarian activity, and pregnancy rate. At weaning, body weight and hip height were significantly different among frame scores, (small -133.0 kg, 92.2 cm; medium -158.5 kg, 96.6 cm; and large -185.2 kg; 100.2 cm). After weaning, heifers grazed together on natural pastures during the autumn and on ryegrass (Lolium multiflorum La.) during the winter and spring. Frame score differences remained until the beginning of the breeding season (BS), starting on average at 14 months of age. Weight gain between weaning and the beginning of BS was not different among frame scores (0.740 kg/day, on average). Body weights at the beginning of the BS were significantly different, of 255.7 kg (53.3% of the mature weight) for small heifers, 285.0 kg (59.4%) for medium heifers, and 307.6 kg (64.1%) for large heifers. Ovarian activity at the beginning of the BS was not different among the three groups. The average weight gain values during the BS of 0.492, 0.472, and 0.421 kg/day for small, medium, and large heifers, respectively, were significantly different. Pregnancy rates were not different among groups (small, 71.4%; medium, 76.4%; and large, 76.5%). Frame score did not influence the reproductive performance of heifers, but the small and medium heifers conceived 29 and 20 days earlier, respectively, than the large heifers.

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Section: Discussioncontrasting

confidence: 47%

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Development and reproductive performance of Hereford heifers of different frame sizes up to mating at 14-15 months of age

et al. 2018

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“…Tabela 2 -Relação peso vivo:altura (P:H), peso vivo (PV) e escore de condição corporal (ECC) aos nove meses (9M) e doze meses (12M) de idade, de novilhas mantidas em pastagem de azevém mineralizadas com sal comum, sal mineral contendo 40 gramas de fósforo por kg de produto ou sal mineral com 40 gramas de fósforo por kg de produto + lasalocida sódica. Para serem logrados bons índices de prenhez ao primeiro acasalamento, no entanto, o peso alvo para manifestação da puberdade, correspondendo a 65% do peso adulto, deve ser atingido antes do início do período de acasalamento (ROCHA & LOBATO, 2002). Para as novilhas do presente experimento, isso inviabilizaria o seu acasalamento aos 13-14 meses de idade, pois elas apresentaram em 18/10 peso correspondente a 58,33 e 56,38% do peso adulto, quando receberam suplementação com e sem ionóforo, respectivamente.…”

Section: -------------------------Períodos De Avaliação--------------unclassified

Desenvolvimento de novilhas de corte sob alternativas de mineralização em pastagem de azevém

et al. 2009

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Foi avaliado o desenvolvimento corporal de bezerras de corte em pastagem de azevém (Lolium multiflorum Lam.), recebendo diferentes alternativas de suplementação mineral, associadas ou não à adição de ionóforo. Os tratamentos testados foram: "Sal comum": mineralização com cloreto de sódio; "Sal 40P": mineralização com sal mineral contendo 40g de fósforo por kg de produto; "Sal 40P + ionóforo": mineralização com 40g de fósforo + 2.000mg de lasalocida sódica por kg de produto. Os valores de proteína bruta, fibra em detergente neutro, Ca e P na forragem aparentemente consumida, consumo de sal, escore de condição corporal, relação peso: altura e GMD foram semelhantes (P>0,05) entre animais que receberam "Sal comum", "Sal 40P" e "Sal 40P + ionóforo". Em pastagem de azevém, sem restrição ao consumo voluntário, a lasalocida sódica adicionada ao sal mineral proporciona maior peso vivo de bezerras aos 12 meses de idade e um retorno financeiro positivo.

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

Eloy

Bremm

Lobato

et al. 2020

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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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Sistemas de Alimentação Pós-Desmama de Bezerras de Corte para Acasalamento com 14/15 Meses de Idade

Cited by 23 publications

References 15 publications

Development and reproductive performance of Hereford heifers of different frame sizes up to mating at 14-15 months of age

Development and reproductive performance of Hereford heifers of different frame sizes up to mating at 14-15 months of age

Desenvolvimento de novilhas de corte sob alternativas de mineralização em pastagem de azevém

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

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