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Berthiaume, Devin

Animal Science

2006

MS

Conventional weaning methods in the United States have restricted intake of milk replacer to supply calves with only minimal amounts of nourishment to encourage the intake of calf starter at an early age. More recently, high protein milk replacers have gained popularity because of their ability to increase lean tissue gain in calves. It has been shown in other countries around the world, as well as in the United States, that calves allowed to consume more milk or milk replacer grow at an increased rate when compared to calves fed on a restricted intake diet. However, research has not been done to investigate the optimum amount of high protein milk replacer that should be fed, and at what age, to optimize preweaning growth rates in calves without compromising health. The current study is a portion of a larger study that aims to correlate future production success of cows to neonatal feeding systems. The intention of this study is to determine differences seen during the neonatal period that can be correlated with feeding method. To achieve this goal, we investigated a conventional feeding level (using 20:20 milk replacer) and compared this with three different high protein (26:18) milk replacer feeding treatments, varied by the day milk replacer volume was first increased. An additional feeding treatment is a parallel to the most aggressive feeding treatment but will examine the effects when starter grain is not offered for 21 days; all other feeding treatments will have starter grain offered 3 days after birth. We monitored body weight gain, average daily gain, feed to gain efficiency, hip height, body temperature, fecal and respiratory score status. Furthermore weekly blood samples were analyzed for immunoglobulin G₁ and A, as well as beta-hydroxybutyrate. Body weight gain from the third week of the study through the remainder of the 8 week period was increased when calves were fed the 26:18 milk replacer versus the 20:20 milk replacer. Among the 26:18 (high protein) treatments, offering milk replacer to calves earlier in life did not result in increased body weights over the study period, despite differences in average daily gain in the first 3 weeks of life. There were no differences between treatments in scouring, respiratory status, rectal temperature, or serology. We determined that feeding increased amounts of crude protein in milk replacer allowed for increased weight gain throughout the first 8 weeks of life. Surprisingly, increasing the amount of high protein milk replacer earlier in life did not yield growth differences, although none of the feeding treatments experienced negative effects on health due to feeding treatment. These heifers will be followed through their first lactation to determine continued growth through parturition and lactation. Age at calving as well as first lactation production (milk yield) will be monitored to determine differences in cow performance that may be attributed to neonatal feeding.