Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/14/2004
Publication Date: 5/23/2004
Citation: Looper, M.L., Aiken, G.E., Flores, R., Rosenkrans, Jr, C.F., Brauer, D.K. 2004. Supplementation influences milk yield and milk components of cows grazing stockpiled tall fescue. International Neotyphodium Grass Interactions. #502. Interpretive Summary: Stockpiling tall fescue can extend the grazing season further into the winter and decrease dependence on costly stored or purchased feeds. The adequacy of stockpiled fescue to supply sufficient nutrients for late term pregnant cows is uncertain. An experiment was conducted to determine if weaning weights of calves born to cows on stockpiled fescue can be enhanced by supplementations. Milk yield and percent milk fat were increased in cows supplemented with soyhulls and grazing stockpiled fescue; however, adjusted 205-d weaning weights of calves from soyhull-supplemented cows were not increased. These results indicate that if availability of stockpiled fescue is adequate, supplementation of cows may not be necessary. This information is of interest to beef producers, extension personnel, and agricultural professionals who advise beef producers on forage/animal management practices.
Technical Abstract: Eighty-eight crossbred cows were assigned to one of three paddocks of stockpiled fescue for 160 d to determine milk yield and components, and determine performance of cows and calves consuming either corn:soybean meal (CSB; n = 28), soyhulls (SH; n = 28), or no supplement (control; n = 32). Supplements were fed at 0.91 kg/d per cow. Fescue paddocks were clipped to a height of 10.2 cm on September 23rd and fertilized on September 25th with 12-20-20 (20 kg N/ha). Paddocks were fertilized again on March 5th with 20-10-10 (65 kg N/ha). Cows were weighed and body condition scored (BCS) at the beginning and end of the experiment. Milk yield was measured at 59.7 ± 0.7 d postpartum (range 43 to 77 d postpartum) by milking machine. Milk samples were collected in duplicate, and milk fat, milk protein, lactose, solids-not-fat (SNF), and milk urea nitrogen (MUN) were determined. Calves were weighed at weaning, and weaning weights were standardized to a 205 d weight. Supplementation did not influence (P > 0.10) body weight and body condition score of cows. Milk yield was increased (P < 0.06) in cows supplemented with SH compared with control cows. Likewise, percent milk fat was increased (P < 0.05) in SH-supplemented cows (4.5%) compared with control cows (3.7%). Cows supplemented with SH had decreased (P < 0.05) percent milk protein and milk urea nitrogen. Adjusted 205-d weaning weights of calves were not different (P > 0.10) between nutritional treatments and averaged 257, 269, and 256 kg (pooled standard error = 3.1) for calves from cows supplemented with CSB, SH, and no supplement (control), respectively. If availability of stockpiled fescue is adequate, supplementation of cows may not be nutritionally or economically necessary.