Calf Starter -- big impact on calf growth


Milk replacer feeding rates have received much attention over the past several years. Many calves these days grow bigger in a shorter period of time mainly due to consumption of more milk or milk replacer. At high intake levels, the role of starter feed in supporting this early growth is often markedly reduced, or at least altered. The quality of calf starter and the structure of the milk replacer feeding program are both major factors in determining the impact of starter in preweaning calf growth.


In general, we expect to see starter intake delayed as milk replacer intake increases. But that's not a hard, fast rule. The table below shows feed consumption results for a research trial comparing two milk replacer formulas and feeding schedules. Calves on the 20-20 (20% protein, 20% fat) all milk protein formula received 16 oz of milk replacer powder in one gallon of water each day, while calves on the 25-15 formula received 24 oz of powder in one gallon of water each day. Calves were fed milk replacer twice daily, had access to free choice water and starter, and were weaned at the end of Week 6.

By the end of week 6, calves on the 20-20 treatment consumed a total of 42 pounds of milk replacer powder, and had eaten 49 pounds of starter feed for a total feed intake of 91 pounds. Calves on the 25-15 treatment consumed 63 pounds of milk replacer powder and also ate 49 pounds of starter feed for a total feed intake of 112 pounds by the end of week 6. During weeks 7 and 8, calves received only starter feed and free-choice water. Feed values in the table are cumulative from the beginning of the trial and are reported on an as-fed basis.

Milk Replacer Research Data

In spite of the different formulas and feed rates, calves on both treatments ate the same amount of starter by weaning. After weaning, calves on the 25-15 treatment consumed more starter than 20-20 calves. The following graph shows the energy intake from the different feed sources during the trial.


Milk Replacer Research Data

Daily energy provided by the two milk replacers are shown by the blue and red horizontal lines. Energy provided by the amount of starter each day is shown by the green line. For calves on the 20-20 program, energy from starter intakes surpassed that provided by the milk replacer at about 4 weeks. This transition point was a couple days later for calves on the 25-15 program. Now consider what happens when starter quality is changed.

 Effect of Starter Quality

The treatment results described above are for calves that received Starter A, pictured below on the left. Starter B was fed to two other treatment groups of 20-20 and 25-15 calves in this trial instead of Starter A. Both starters were commercially available and had similar nutrient analyses. Starter B is obviously a drier feed, with little molasses, more pellets, less grain and more small, broken particles (fines).

Starter A                                      Starter B

Calf response to Starter B is shown in the graph below. The transition point where energy from starter intake surpassed that of milk replacer was delayed more than a week for the 20-20 calves and was pushed back to weaning time for the 25-15 calves. By week 8, Starter B calves were eating 3 pounds per day less starter than calves on Starter A. As a result of starter quality differences, 20-20 and 25-15 calves on Starter A averaged 18 and 20 pounds heavier, respectively, than their counterparts on Starter B by the end of week 8.

Milk Replacer Research Data


Effect of Milk Replacer Program

 Another reason for starter intake depression is the design of the milk replacer feeding program. The following table shows the results of a trial comparing milk replacer and starter intakes for calves on a 25-15 program to calves on a 28-20 program. Calves on the 25-15 treatment were fed 1.5 pounds of milk replacer powder per day whereas the 28-20 calves received 1.88 pounds of powder per day during the first week. The feeding rate for 28-20 calves was increased to 2.6 pounds per day during weeks 2 through 6, and dropped to 1.3 pounds per day during week 7. Calves were fed milk replacer twice daily and had access to free choice water and starter. Calves on the 25-15 treatment were weaned at the end of week 6, and 28-20 calves were weaned at the end of week 7.


Milk Replacer Research Data


By the end of week 6, the 25-15 calves had consumed 41 pounds less milk replacer powder and 25 pounds more starter than the 28-20 calves -- that's nearly double the starter intake. By the end of the trial, the 25-15 calves had consumed 50 pounds less milk replacer powder and 45 pounds more starter than the 28-20 calves -- that's one bag less milk replacer and one bag more starter. Although not reported in the table, the 28-20 calves were significantly heavier (p<0.05) at the end of weeks 2 and 3, were only 4 pounds heavier at the end of week 6, and were the same weight as the 25-15 calves by the end of week 8.

The Gross Energy Intake graph provides insight into what's going on with the two treatments. Energy intake with the 25-15 and 28-20 programs is shown by the red and blue lines, respectively. Energy from starter intake of the 25-15 calves, the purple line, shows that starter became the major energy source for those calves just prior to the end of week 4. Energy from starter intake of the 28-20 calves didn't cross that point until weaning at 7 weeks.

Milk Replacer Research Data

By week 4, the difference in total daily energy consumption between the two groups had narrowed substantially, and by week 6, daily energy intakes were virtually the same. During weeks 7 and 8, the 25-15 calves consumed more energy than 28-20 calves.

These intake and growth results show that 28-20 calves lag behind as they approach weaning, and strongly suggest that calves could benefit from modifications to this milk replacer feeding approach. These calves certainly can't afford any intake lag due to starter quality and composition issues. Increasing the number of milk feedings per day might be one way to help improve starter intake -- perhaps for both groups, and adjustments to the 28-20 feeding rates may help reduce the growth lag and need for these calves to catch up. With total feed costs about 60% higher with this 28-20 program, the only time you'd expect calf weights to be the same is on day 1.