Estimativa de la edad y peso a la primera monta de novillas en el Pantanal brasileño

Sereno, J. R. B.; Pellegrin, A. O.; Lara, Maria Aparecida Cassiano; Abreu, U. G. P. de; Sereno, Fabiana Tavares Pires de Souza; Chalita, Liciana Vaz de Arruda Silveira

doi:10.1590/s0100-204x2001001200014

Cited by 3 publications

(4 citation statements)

References 2 publications

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“…Several farmers in Brazil aim to begin the heifers' reproductive life around 26 months of age (Gunski et al, 2001;ABCZ, 2016). However, it does not occur in the majority of Brazilian cow-calf systems, in which heifers are usually bred only when they are >3 years of age (Gunski et al, 2001;Sereno et al, 2001). Thus, the difference in the percentage of pubertal heifers between LLG and HLG treatments has immediate applicability to the beef cattle industry.…”

Section: Figurementioning

confidence: 99%

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A combination of nutrition and genetics is able to reduce age at puberty in Nelore heifers to below 18 months

Ferraz

Pires

Santos

et al. 2018

Animal

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Nelore heifers usually begin their reproductive life at ⩾24 months of age mainly due to suboptimal nutritional conditions and genetics. This study aimed to determine the effect of expected progeny difference (EPD) for age at first calving and average daily gain (ADG) on puberty in Nelore (Bos taurus indicus) heifers. A total of 58 weaned heifers (initial BW=174±6 kg; age=9±1 months) were allocated into 28 feedlot pens. Heifers were born from four sires, of which two had low EPD for age at first calving (L; n=33) and two had high EPD for age at first calving (H; n=25). Then, heifers of each EPD were randomly assigned to high ADG (HG; 0.7 kg) or low ADG (LG; 0.3 kg), resulting in four treatments: heifers from L sires were submitted to either HG (LHG; n=17) or LG (LLG; n=16), and heifers from H sires were submitted to either HG (HHG; n=12), or LG (HLG; n=13). The HG heifers were fed a 75% grain diet, whereas the LG heifers received 93% of forage in their diet. Blood samples were collected at 9, 14, 18, 24 and 28 months of age for IGF1 and leptin determination. There was a treatment effect (P<0.01) on the proportion of heifers that attained puberty by 18 (62%, 0%, 0% and 0%), 24 (100%, 6%, 54% and 0%) or 36 (100%, 100%, 100% and 38%) months of age for LHG, LLG, HHG and HLG treatments, respectively. In addition, mean age at puberty was different across treatments (P<0.01). Heifers from the LHG achieved puberty at the earliest age when compared with cohorts from other treatments (18.1, 28.9, 23.9 and 34.5 months for LHG, LLG, HHG and HLG, respectively). Serum IGF1 concentrations were higher for L heifers compared with H cohorts at 9, 14, 18, 24 and 28 months of age (P<0.01; treatment×age interaction), whereas circulating leptin concentrations were higher (P<0.01; age effect) as heifers became older, regardless of the treatments. In conclusion, only Nelore heifers with favorable genetic merit for age at first calving were able to attain puberty by 18 months of age. In heifers with unfavorable genetic merit for age at first calving, supplementary feeding to achieve high ADG was unable to shift the age at puberty below 24 months.

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Section: Figurementioning

confidence: 99%

“…Nelore is the major breed beef cattle in Brazil and the heifers usually reach puberty from 2 to 3 years of age, weighing~300 kg (Gunski et al, 2001;Sereno et al, 2001;Nepomuceno et al, 2017). According to the Brazilian Association of Zebu Breeders, the average age at first calving in Nelore is 38 ± 5 months (ABCZ, 2016).…”

Section: Introductionmentioning

confidence: 99%

A combination of nutrition and genetics is able to reduce age at puberty in Nelore heifers to below 18 months

Ferraz

Pires

Santos

et al. 2018

Animal

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“…A diferença obtida entre os tratamentos PGB e TGB também é importante e com aplicabilidade imediata na pecuária de corte, uma vez que vários produtores já têm como meta emprenhar as novilhas ao redor dos 26 meses de idade (GUNSKI et al, 2001). No entanto, isso ainda não é uma realidade da pecuária nacional, na qual é comum a novilha emprenhar com mais de 3 anos de idade (GALINA; ARTHUR, 1989;GUNSKI et al, 2001;SERENO et al, 2001;ABCZ 2013 Outro ponto interessante mostrado neste trabalho foi que durante os meses de junho, julho e agosto nenhuma novilha entrou em puberdade. E em setembro, houve aumento acentuado na proporção de novilhas que entraram em puberdade.…”

Section: Discussionunclassified

“…A principal raça de gado de corte criada no Brasil é a Nelore e as novilhas dessa raça nos sistemas de criação comumente encontrados no Brasil são tardias, ou seja, entram na vida produtiva com 2 a 3 anos de idade, ou até mais velhas (GALINA; ARTHUR, 1989;GUNSKI et al, 2001;SERENO et al, 2001). Apesar dessas referências serem antigas, a idade média ao primeiro parto ainda continua perto dos 3 anos de idade, segundo o sumário da ABCZ (2013) a evolução dessa característica foi de 39,9 em 1991 para 36,5 meses de idade em 2012.…”

Section: Introductionunclassified

<b>Puberdade de novilhas:</b> 1 - Efeito da nutrição e da DEP do touro para precocidade sexual na puberdade de novilhas Nelore; 2 - Efeito da desmama precoce e da nutrição no <i>imprinting</i> metabólico sobre a puberdade de novilhas Nelore e cruzadas (Angus x Nelore)

Júnior¹,

Castro²

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Agradeço a Deus por guiar minha consciência e entendimento, de modo que eu possa progredir na minha existência e por poder contar com diversas mãos que fizeram possível esse trabalho. Para elas tenho lágrimas de gratidão! Aos meus pais, espero um dia retribuir tudo o que fazem por mim.Ao meu irmão Matheus, amizade e simpatia.Aos meus Avós e à minha Madrinha, respeito, amizade e gratidão.À Márcia, desejo-lhe um futuro de flores.Ao Prof. Dr. João Bosco Barreto Filho, obrigado por me iniciar na pesquisa e pela amizade. The objective of experiment I was to evaluate the interaction between two average daily gain (ADG -nutritional factor (high gain HG = 0,700 and low gain LG = 0,300 kg/day)] and expected progeny differences (EPD to age at first calving; genetic factor) on puberty attainment of Nellore heifers. Fifth eight heifers weaned at 8 months of age and daughters of 4 sires [2 precocious (P) and 2 later (L)]. A factorial design 2 x 2 was used, where the factor 1 was the ADG and the factor 2 was the EPD of sire, resulting in four treatments: Precocious sire with HG (PHG), precocious sire with LG (PLG), later sire with HG (LHG) and later sire with LG (LLG). There was effect of treatment in the percentage of pubertal heifers (PHG and PLG = 100%; LHG = 83% until 27 month of age; LLG = 38% until 3 years old). Heifers from the PHG treatment were the youngest (P = 0,0001) (18 months of age). However, the nutritional factor delayed puberty achievement by approximately 10 months the age at puberty in precocious and later heifers (PHG = 18 ± 1 vs. PLG = 29 ± 1 months; LHG = 24 ± 1 vs. LLG = 34 ± 1 months of age). The EPD to age at first calving was the main factor affecting the age at puberty. However, the ADG was limiting to puberty onset. The objective of experiment II was to evaluate the effect of metabolic imprinting from 3 to 7 months of age on puberty attainment of crossbreed heifers (Angus x Nellore). The treatments were arranged in 2 x 2 factorial design, where the factor 1 was high (H) and medium (M) ADG from 3 to 7 months of age (phase 1) and the factor 2 was high and medium ADG from 7 months of age to puberty onset (phase 2), resulting in the following treatments: CHH -crossbreed heifers submitted to high ADG in both phases of experiment; CHM -high ADG in phase 1 and medium ADG in phase 2; CMH -medium ADG in phase 1 and high ADG in phase 2; CMMMedium ADG in both phases. The medium ADG were targeted by restricting of dry mater intake (DMI) in medium ADG. Crossbreed heifers of treatments CHH, CHM, CMH showed the same age at puberty, about 12 months. Heifers submitted to high ADG on phase 2 were heavier (P = 0,0379) at puberty than heifers submitted to low ADG. The high ADG from 3 to 7 months did not affect puberty onset in crossbreed heifers. The objective and methodology used in experiment III was the same of used in experiment II. However, Nellore heifers (N) were used instead of crossbreed heifers and the experimental period ended at 19 months of age. The NHH treatment (84%) induced higher (P = 0,0145) percen...

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Anti-Müllerian Hormone (AMH), antral follicle count (AFC), external morphometrics and fertility in Tabapuã cows

Maculan

Pinto

Moreira

et al. 2018

Animal Reproduction Science

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Estimativa de la edad y peso a la primera monta de novillas en el Pantanal brasileño

Cited by 3 publications

References 2 publications

A combination of nutrition and genetics is able to reduce age at puberty in Nelore heifers to below 18 months

A combination of nutrition and genetics is able to reduce age at puberty in Nelore heifers to below 18 months

<b>Puberdade de novilhas:</b> 1 - Efeito da nutrição e da DEP do touro para precocidade sexual na puberdade de novilhas Nelore; 2 - Efeito da desmama precoce e da nutrição no <i>imprinting</i> metabólico sobre a puberdade de novilhas Nelore e cruzadas (Angus x Nelore)

Anti-Müllerian Hormone (AMH), antral follicle count (AFC), external morphometrics and fertility in Tabapuã cows

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