A group of Brazilian researchers examined the use of total solids (TS) with liquid feed on feed intake and development of dairy heifers. The group published their results in the Journal of Dairy Science.
“Recommendations for the maximal concentration of TS in liquid feed are still not well established, and further research on the effects of different concentrations of liquid feed TS on calf performance is needed,” said team members in the study. “The objective of this study was to evaluate the effect of increasing the concentration of TS in whole milk on feed intake, performance, body frame development, feed efficiency, and health in heifers during the pre- and post-weaning periods by adding milk replacer powder.”
The research team found that boosting the amounts of TS for the heifers supported improved final body weight, growth performance and average daily gain, while limiting feed efficiency for both the pre- and post-weaning periods.
“Increasing the concentration of TS in liquid feed up to 20.4% increased performance and body frame development in dairy heifers during the pre- and post-weaning periods and had no effects on solid feed intake or health,” said the researchers.
Why added solids?
Although restricting milk intake before weaning has been a common practice, that process has been challenged in recent studies, said the researchers.
“Kiezebrink et al. (2015) and Yunta et al. (2015) have demonstrated that calves given restricted amounts of liquid feed are unable to ingest sufficient nutrients to ensure satisfactory ADG[average daily gain],” they said. “In addition, adequate nutrient intake during the pre-weaning period is essential for calf well-being, health, and future productivity.”
Calves getting more milk or milk replacer have been found to have better growth rates, health and immune functioning post-weaning, and the additional feed does not delay rumen development, they said. But, many producers are slow to change practices because of the added expense.
Milk is one way to provide nutrition for heifers, but “balancers” also can be added to the liquid feed, said the researchers. The products increase the TS content in milk or milk replacer without altering how much milk is provided.
There is no set standard for the use of balancers, they said. And, osmolality of the liquid feed has to be examined as TS amounts are raised as information on reference values is needed.
Study details
In the trial, 60 heifers were given one of four diets for two periods of time – from 5-55 days of age and for days 56-59, said the researchers. The diets included 12.5, 15, 17.5 and 20% of a commercial balancer or TS in a whole-milk based feed.
From days 5-55, the diet was 6L of liquid feed in two meals a day and from day 56-59 liquid feed was reduced by half, they said. Cows were weaned at day 60 and then watched through day 90.
A starter feed and water were also on offer to the animals throughout the study, they said. Corn silage was added on day 70 and heifer nutritional intake, starter and corn silage consumption were recorded.
Heifers were monitored for feed intake, dry matter (DM), crude protein (CP) and gross energy intake, health and fecal consistency daily, while body weight, heart girth, rump width and frame development were noted weekly through day 90, said the researchers. Ruminal pH was checked every 14 days.
Samples of milk and liquid feed also were collected and checked for TS, CP, fat content and osmolality, and the starter, milk replacer powder and corn silage were analyzed, they said.
Results
During the pre-weaning period, starter intake, fecal scores and ruminal pH at weaning were similar, said the researchers. Growing amounts of TS in the feed produced a linear increase in average daily gain, final body weight and growth performance but reduced feed efficiency.
“After week four, we observed a similar intake of whole milk + MRP (kg/d) among treatments,” they said. “However, intake of whole milk + MRP (g of DM/d) increased with concentration of TS in the liquid feed, as initially proposed in the experimental design.”
Calf intake of CP and gross energy also grew with level of TS, they said.
Post-weaning intake of starter, corn silage and water were similar, said the researchers. Average daily gain and feed efficiency also were closely matched, but final body weight and growth performance increased linearly with TS concentration.
“Withers height was similar across treatment groups during the post-weaning period, but heart girth and hip width increased with the concentration of TS in the liquid feed, indicating that the differences in body frame development observed during the pre-weaning period were maintained in the post-weaning period up to 90 d of age,” they said.
Source: Journal of Dairy Science
Title: The effects of increasing amounts of milk replacer powder added to whole milk on feed intake and performance in dairy heifers
Authors: R. Azevedo, F. Machado, M. Campos, P. Furini, S. Rufino, L. Pereira, T. Tomich, S. Coelho