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CALF SUCCESS Dairy Calf Research Update - by Bruce Ziegler What is the best crude protein level for calf starters? Most research that has focused on ideal calf starter protein levels was completed 20+ years ago and it suggested no benefit to feeding more than an 18% “as-fed” crude protein starter to Holstein dairy calves through 2 months of age. Structural growth and ADG did not improve with higher protein levels. With dramatically improved cattle genetics and on farm management, today’s Holstein is much different than it was 20+ years ago. Dry matter intake and production per cow has improved dramatically. What about the calf? Has its nutritional needs changed as its dam has changed over the years? In research at the U of M Southern Research and Outreach Center’s (SROC) Calf and Heifer Research facility in Waseca, MN, average starter intake has improved consistently since their research program started focusing on calves in 2004. Hubbard and the staff at SROC designed and conducted a trial in fall of 2014 to evaluate crude protein levels in our Elite texturized calf starter line. Two to five day old calves were randomized across 4 treatments: 1) 15%CP- 15% crude protein starter, as-fed; 2) 18%CP- 18% crude protein starter, as-fed; 3) 21%CP- 21% crude protein starter, as-fed; 4) 24%CP- 24% crude protein starter, as-fed; Calves were fed 10 ounces of Calf Beginner 20-20 all milk protein milk replacer in two quarts of water twice a day for 35 days, once a day for 7 days and weaned by day 42. All calves received free choice water and starter for the entire 56 day trial. Calves were weighed upon arrival and at 14 day intervals through 56 days. Starter intake was monitored daily and summarized every 14 days. Calf starter and milk replacer refusals were measured daily. Effect of Starter Crude Protein Level on Starter Intake: Starter intake decreased linearly as crude protein level increased. Total 56 Day Starter Intake, DM basisa 140.0 130.0 130.4 lbs 129.7 125.2 120.0 118.2 110.0 100.0 Day 1-56 15%CP 18%CP a-Linear reduction in starter intake, P= 0.027 21%CP 24%CP Effect of Starter Crude Protein Level on Average Daily Gain and Hip Height Gain: ADG and Hip Height Gain were maximized at 18-21% crude protein. Growth parameters were decreased with less than 18 or more than 21% crude protein. Average Daily Gaina Hip Height Gain Day 1-56a 1.70 4.40 1.60 1.40 1.30 1.20 4.00 3.90 3.80 15%CP Day 1-56 1.54 18%CP 1.43 1.66 3.60 21%CP 1.40 1.66 1.31 4.33 4.10 Day 1-42 1.34 24%CP 4.36 4.20 inches lbs/hd/day 4.30 1.50 4.02 3.89 3.70 15%CP 1.53 Day 1-56 18%CP 21%CP 24%CP a- Quadratic effect of protein level, P=0.02 a- Day 1 -56, Quadratic effect of protein level , P= 0.006 Effect of Starter Crude Protein Level on 42 day Serum Beta Hydroxy Butyrate: Serum BHBA, a measure of rumen development, was maximized with 18-21% crude protein starter. Serum Beta Hydroxy Butyratea 0.70 0.60 0.60 mg/dl 0.50 0.51 0.51 0.40 0.30 0.37 0.20 0.10 0.00 15%CP Day 1-56 18%CP 21%CP 24%CP a- Quadratic effect of protein level, P=.004 Bottom Line: In this trial, when calves were fed a conventional milk replacer feeding program, along with a high quality starter, feeding an 18-21% crude protein starter maximized intake, growth and rumen development. Feeding a lower crude protein starter level decreased growth and rumen development while feeding a higher crude protein starter decreased growth. What is the best crude protein level in calf starters? Based on this research, 18-21% crude protein starter provides excellent growth and performance when calves are fed a conventional calf feeding program, while an 18% crude protein starter will be most economical. Hubbard Feeds Products and Answers that WORK