Bovis ISSN 2398-2993

Estrus: the cow not observed in estrus

Synonym(s): Not seen bulling

Contributor(s): Jonathan Statham , James Breen

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Estrus detection

  • Estrus: signs and detection.
  • Creating more chances to become pregnant, through improved submission rates, is more important and effective than the success rate of a single chance.  
  • Estrus detection has been described as the central event in the success of bovine reproduction, particularly when artificial insemination (AI) is used Artificial insemination.
  • The rate of estrus detection is commonly quantified by the 24-day submission rate.
    • This is defined as the number of cows served within a 24 day period, expressed as a percentage of the number of cows that have passed their voluntary waiting period (VWP) at the start of the 24 day period.
Submission rate= Number of eligible cows inseminated in target period x 100 / Number of eligible cows
  • Traditionally, estrus detection has been via visual observation of behaviors linked to estrus.
  • This requires a skilled observer, sufficient observation time and for cows showing overt signs of estrus.
  • The trend towards larger herds has increased the numbers of cows per herdsman and decreased the amount of time available for observations.

Declining estrus expression: 'subestrus'

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How can submission rates be improved in practice?

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Further Reading


Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Capper J (2011) The environmental impact of dairy and beef production: improving productivity offers mitigation opportunities. Cattle practice 19 (2), 137-141.
  • Caldow G, Riddell I, Stuart H & Lowman B (2007) Improving Efficiency of the Beef Cow Herd. Cattle Practice 15 (2), 138-144.
  • Berardinelli J G & Joshi S A (2005) Initiation of postpartum luteal function in primiparous restricted-suckled beef cows exposed to a bull or excretory products of bulls or cows. J Anim Sci 83, 2495–2500 PubMed.
  • Caldow G, Lowman B & Riddell I (2005) Veterinary intervention in the reproductive management of beef cow herds. In Practice 27 (8), 406-411.
  • Berardinelli J G & Joshi S A (2005) Introduction of bulls at different days postpartum on resumption of ovarian cycling activity in primiparous beef cows. J Anim Sci 83, 2106–2110 PubMed.
  • Bollwein H, Weber F, Kolberg B & Stolla R (2002) Uterine and ovarian blood flow during the estrous cycle in mares. Theriogenology 57 (8), 2129-38 PubMed.
  • Bollwein H, Meyer H H, Maierl J, Weber F, Baumgartner U & Stolla R (2000) Transrectal Doppler sonography of uterine blood flow. Theriogenology 53 (8), 1541-52 PubMed.
  • Arney D R, Kitwood S E & Phillips C J C (1994) The Increase in Activity During Estrus in Dairy Cows. Applied Animal Behaviour Science 40, 211-218.
  • Bobowiec R., Studzinski T & Babiarz A (1990) Thermoregulatory effects and electrical conductivity in vagina of cow during oestrous cycle. Arch Exp Veterinarmed 44, 573–579 PubMed.
  • Baker A A (1965) Comparison of heat detectors and classical methods for detecting heat in beef cattle. Aust Vet J 41, 360.

Other sources of information

  • Beerwinkle L G (1974) Heat detection programs and techniques. NAAB 8th Annual Conference on Beef AI.