Bovis ISSN 2398-2993

Cold stress: calves

Contributor(s): Mike Reynolds , Keith Cutler

Introduction

  • Cause:
    • Harsh winter conditions.  Cold climatic conditions are further exacerbated by wind and precipitation, with the latter having a negative effect on calf survival.
    • Within a range of environmental temperatures known as the  “thermoneutral zone,” animals do not have to expend any additional energy to maintain their body temperature.
      • At the lower end of this range, normal metabolic processes supply enough heat to maintain body core temperature.
      • Within their thermoneutral zone, animals may modify their behavior to stay warm, but will not require additional nutrition.
      • If, however, temperatures drop below the lower limit of the thermoneutral zone then the animal experiences cold stress.
      • To combat cold stress, the animal must increase its metabolic rate to supply more body heat.
      • As a result of these increased maintenance energy requirements, productivity is compromised.
    • Hypothermia occurs when the body temperature drops below normal.
      • Mild hypothermia: body temperature of 30°C-32°C, (86°F-89°F)
      • Moderate hypothermia: body temperature at 22°F-29°C, (71°F-85°F).
        • Once rectal temperature drops below 28°C (82°F), cows are not able to return to normal temperature without human assistance.
      • Severe hypothermia: body temperature below 20°C (68°F).
  • Signs: See below.
  • Diagnosis: Clinical signs consistent with disease, core body temperature, blood gas analysis.
  • Treatment:  See below.
  • Prognosis: Guarded.

Pathogenesis

Etiology

  • Extreme climatic conditions that cannot be compensated by thermoregulatory mechanisms result in thermic stress.
  • Thermoregulatory responses for heat generation include shivering and non-shivering thermogenesis such as an increased metabolic rate, piloerection and peripheral vasoconstriction.
  • Moisture and wind/draughts will severely exacerbate the effects of cold conditions.
  • In neonatal calves metabolism of brown fat reserves and ingestion of colostrum plays an important role in thermoregulation.
  • Healthy calves are physically active, which increases heat production and cold resistance. However, newborn calves are prone to heat loss under cold conditions because of their low surface/mass-ratio and poor insulation.
  • Inclement weather and cold stress will also reduce immune competence in neonatal calves. Cold stress decreases neutrophil chemotaxis and vasoconstriction reduces leukocyte distribution to peripheral tissues.

Predisposing factors

General

  • Adverse weather conditions.

Specific

  • Inclement weather conditions exacerbated by wind, drafts and precipitation.
  • Anorexia or lack of provision of sufficient or appropriate feed to support metabolic demand for heat generation and maintenance.
  • Failure of passive transfer and concurrent sepsis.

Timecourse

  • Hours to days.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMed Resource.
  • Roland L, Drillich M, Klein-Jobstl & Iwersen M (2016) Invited review: Influence of climatic conditions on the development, performance and health of calves. J Dairy Sci 99, 2438-2452 PubMed.
  • Mader T L & Griffin D (2015) Management of Cattle Exposed to Adverse Environmental Conditions. Vet Clin North Am Food Anim Pract 31 (2), 247-258 PubMed.
  • Brumbaugh G W (2003) Neonatal Adjustments. Vet Clin North Am Food Anim Pract 19 (3), 551-556 PubMed.
  • Olson D P, Papasian C J & Ritter R C (1980) The Effects of Cold Stress on Neonatal Calves 1. Clinical Condition and Pathological Lesions. Can J Comp Med 44, 11-18 PubMed.

Other sources of information

  • www.omafra.gov.on.ca/english/livestock/beef/facts/07-001.htm
  • House J K, Smith G W, McGuirk S M, Gunn A A, Izzo M (2015) Manifestations and Management of Disease in Neonatal Ruminants. In: Smith B P Large Animal Internal Medicine.  5th Edition. pp 302-338.
  • White M E & Fecteau S L (2015) Alterations in body temperature. In: Smith B P Large Animal Internal Medicine. 5th Edition. pp 39.


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