04-Calves & heifers

04-Calves & heifers - Calf and Heifer Development Dr....

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Unformatted text preview: Calf and Heifer Development Dr. Howard Tyler Department of Animal Science Iowa State University Pre-Weaning Management s First day of life s Management can affect the lifetime profitability of an animal s Improve feed efficiency and rate of gain s Improve health throughout rearing period s Allow optimal expression of milk production s Focus on reducing the stress of the birth process and maximizing passive immunity s 1 Day to Weaning s Management affects total heifer raising costs s Highest risk of disease s Affects milk production as mature cow s Focus on costs, health, and growth rates How Are We Doing? s Reducing stress at birth s ~9% stillbirth rate s Maximizing passive immunity s ~40% of calves have failure of passive transfer s First 2 months of a 24-month rearing period (8% of rearing period): s Take over 50% of vet and medicine costs s 15% of feed costs to get 6% of weight gain s 25% of labor costs s Well over 90% of mortality losses s ~20% death loss from birth to weaning (~2% from weaning to calving) s <1 lb./day average rate of gain from birth to weaning Normal Presentation Birth Weight Issue s Optimal birth weight of calf is dependent on the size of the cow carrying the calf s Calf weight ~6.5% of the dam weight s Birth weights above/below optimal weight increase the risk of dystocia and stillbirth s Currently, average weight of Holstein calves is higher than 6.5% of cow s Re-evaluate trends in genetic selection Dystocia s Any abnormal or difficult delivery process s Poor communication between the fetal calf and it’s dam s Malpresentation of the calf s Difficulties due to inappropriate assistance s Scoring system for calving ease s 5 point system s Score of 1 represents unassisted delivery s not necessarily an easy delivery! s unattended always scored as a “1” s Score of 5 represents extreme force s not necessarily required force Fig 45-1. Malpresentations, such as this backwards presentation, are more common in multiparous than in primiparous cows (Courtesy of Howard Tyler) Dystocia s 70-98% of calf deaths are related to calving difficulties s Calf mortality increases with increasing calving-ease scores s Calf mortality doubles even with SLIGHT assistance at calving s Calf mortality ~50% with calving ease score of 5 s Most calf deaths are associated with lack of oxygen or trauma during delivery s Inappropriate timing of assistance or excessive force s Calf jacks or forceful manual extractions can fracture bones s Often traumatic injuries remain undiagnosed Fig 45-2. Mechanical calf jacks can generate over 1700 pounds of force on the calf and should only be utilized in extreme situations and with extreme care (Courtesy of Iowa State University) Multiple Births s Twins occur in 2-3% of all births s Triplets in 1 out of 10,000 births s Individual twin weights are ~20% lighter than single calf weight Caring for Calf After Birth s Immediately remove calf from dam to a thermoneutral environment s Stimulate breathing if necessary s First breath must be a gasp, as it...
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This note was uploaded on 02/14/2012 for the course ANS 235 taught by Professor Kilmer during the Fall '08 term at Iowa State.

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04-Calves & heifers - Calf and Heifer Development Dr....

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