Effects of short term cold exposure on the digestion of milk replacer by young preruminant calves.

Two groups, totalling 29, of 24-day-old Friesian bull calves were offered 0.6 kg milk replacer reconstituted in 2.5 litres warm water once daily and were housed for a period of 14 days at a temperature of either 3 +/- 2 degrees C (cold) or 18 +/0 0.5 degrees C (warm). Mean daily liveweight gains of the groups exposed to cold or warmth were 0.26 and 0.36 +/- 0.04 kg per day respectively (P less than 0.05). Apparent digestibility coefficients of dry matter, nitrogen and fat of the milk replacer were not affected by exposure of the calves to cold and were 0.95 +/- 0.01, 0.92 +/- 0.01 and 0.77 +/- 0.02 respectively for both groups. Water intake and urine volume were significantly (P less than 0.05) reduced by 1.77 and 0.56 litres per day respectively whereas faecal water excretion was increased ty 0.06 litres per day in the cold exposed calves. Over the 10-day period the warm exposed calves were estimated to make a net water retention while there was a net loss of 0.35 litres per day for the group exposed to cold.