Ad Libitum or Twice Daily Feeding of Acidified Milk Replacer to Calves Housed Individually in Warm and Cold Environments

Forty-two Holstein calves were assigned randomly to treatments in a 2 × 2 factorial arrangement of two milk replacer feeding systems (ad libitum vs. twice daily feeding of cold acidified milk replacer) and two housing types (warm vs. cold). The objectives were to compare the cold ad libitum system with a twice daily regimen and to evaluate its use under two housing types. For wk 1 to 5, calves fed ad libitum consumed more dry milk replacer (.86 vs. .65 kg/d), less calf starter (.07 vs. .15 kg/d), and less free choice water (.50 vs. 1.29 kg/d) than calves fed twice daily. Gains for ad libitum vs. twice daily were not different, but were significantly higher for cold than warm housing possibly due to respiratory problems in the barn. Calves did not increase consumption of replacer in response to cold housing. For wk 6 to 8, no differences in intake were observed, but daily gains were higher for calves in warm housing (.74 vs. .49 kg). There were no differences in weights or daily gain at 24, 36, or 52 wk of age. Plasma glucose was higher for calves fed ad libitum (127.1 vs. 110.6 mg/dl). All calves showed two distinct plasma glucose peaks during a day, indicating that calves fed ad libitum may consume two meals per day instead of small frequent meals. Ad libitum feeding of acidified replacer did not result in improved growth despite higher replacer intakes. There were no differences in response to ad libitum feeding in warm or cold housing.