Effects of Starch and Fat Concentrations in Starter Grain on Jersey Calf Performance
The development of replacement heifers is important for maintaining herd size and financial efficiency of dairy farms. We investigated the nutritional needs of Jersey calves, focusing on meeting nutritional requirements by altering starch and fat concentrations in calf starters. Thirty-six female Jersey calves were grouped by body weight (BW) and birth date and randomly assigned to one of three calf starters: 35% starch and 2% fat (typical calf starter; HST), 20% starch and 2% fat (LST), and 35% starch and 4% fat (HST-F). All calves were fed the same milk replacer at 4.4 L/d during week one, 5.2 L/d during weeks 2 to 7, and 2.6 L/d during the week prior to weaning. Body weight and wither heights were measured weekly. One week after weaning, fecal and feed samples were collected daily for 3 days with the fecal collections representing the 24 hr period of a day. Using the internal marker of acid insoluble ash, apparent digestibility of dry matter (DM), neutral detergent fiber (NDF), and crude protein (CP) were determined. Neither starter (730, 693, and 716 g/d, respectively for HST, LST, and HST-F) nor DM intakes (1259, 1209, and 1245 g/d, respectively) differed among treatments, and there were no differences for treatment by week interactions. Average daily gains from birth through week 10 of age were similar among groups (0.586, 0.534, and 0.550 kg/d, respectively), and thus body weights and wither heights were similar across weeks of the experiment. Digestibilities of dry matter (73.4, 66.0, and 70.2%, respectively), NDF (41.6, 50.2, and 41.4, respectively), and CP (67.6, 65.1, and 62.6, respectively) were similar among treatments. Even though animal performance and diet digestibilities were similar, animal health measures will be further explored and diet cost relative to animal performance will be evaluated.