Puberty in Heifers

Physiological events leading up to puberty

Endocrine and morphological events in peripubertal heifers are similar to the resumption of cyclicity post partum in mature cows.

  • Decreased negative feedback of oestradiol
  • Maturation of the hypothalamus
  • Increased frequency of release of LH pulses
  • Enhanced development of ovarian follicles
  • Enough oestradiol produced to induce behavioural oestrus and a preovulatory surge of gonadotrophins

Puberty is attained with the first behavioural oestrus that is accompanied by ovulation and development of a corpus luteum with a typical lifespan.

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What influences the onset of puberty in heifers?

Factors that can influence the pubertal rise in release of LH pulses are:

  • genotype
  • season of year when pubertal age is attained
  • growth or nutritional intake
  • social cues
  • treatment with exogenous hormones

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Standard values in pubertal heifers

There are slight differences in the age at which heifers reach puberty and start cycling. Body weight is one of the factors which strongly influence the onset of puberty in cattle.

Physiological age of puberty attainment in various cattle breeds
Breed Age at puberty
(months)
Weight at puberty (kg)
Holstein Frisian – US type12-13 265-289
HF – Australian type 8-12 200-230
Jersey8-10 160-180
Brown Swiss10-11 280-300
Charolais12-13 320-355
Angus13-14 300-310
Hereford14-15 300-310
Simmental 11-12 320-330
Zebu type 17-27 330-350

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