Effects of a mixture of steam-flaked corn and extruded soybeans on performance, ruminal development, ruminal fermentation, and intestinal absorptive capability in veal calve
Effects of a mixture of steam-flaked corn and extruded soybeans on performance, ruminal development, ruminal fermentation, and intestinal absorptive capability in veal calve
INTRODUCTION
Feeding calves exclusively with milk not only reduces the physiological growth of the calf’s forestomach but also disrupts the calf’s health status. Therefore, solid feed is important for rumen microbial activity and development in dairy calves. Naturally, different types of feed are associated with different outcomes.
The inclusion of steam-flaked corn in starter feed is associated with increased papillae length and propionate production in the rumen, which improves feed efficiency and average daily gain (ADG). It has also been reported that the presence of raw soybean in starter feed leads to inadequate rumen papillae development. The simultaneous use of steam-flaked corn as an energy source and extruded soybean as a protein source can enhance energy and protein efficiency by improving the nutritional value of the feed. In the study by Xie and colleagues, the combined use of these two energy and protein sources in starter feed was evaluated for its effects on performance, rumen development, rumen fermentation variables, and intestinal absorption capacity in dairy calves.
MATERIALS AND METHODS:
Thirty-nine calves with an average age of 2 days, which were fed one colostrum meal and four transitional milk meals, were then assigned to three treatments for a duration of 150 days:
- Control treatment: Feeding with milk replacer at 1.9% of body weight
- Free feeding with half the volume of milk replacer in treatment 1, along with a starter feed containing 30.5% extruded soybean and 62.1% steam-flaked corn
- Free feeding with a starter feed containing 30.5% extruded soybean and 62.1% steam-flaked corn.
RESULTS AND DISCUSSION:
Each 30-day period was considered a trial phase, resulting in 5 periods for each calf in the experiment. Body weight and ADG during the 2nd and 3rd periods were highest in the control group compared to others. However, the final body weight at the end of the experiment did not differ significantly between the treatments. This could be attributed to stress caused by weaning. It was also reported that although daily dry matter intake in Treatment 3 was higher than other treatments from the 3rd to the 5th period, feed efficiency was lower from the 2nd to the 5th period.
The total volatile fatty acids (VFA) present in the rumen can result from starch, consumed solids, and fermentation of organic matter by rumen microbes. Therefore, this indicator was lowest in calves fed with the control treatment. The molar ratio of propionate in the rumen is related to the non-fiber carbohydrates in the concentrate starter. Hence, calves with the highest dry matter intake (Treatment 3) showed higher concentrations of propionate and butyrate. It has been reported that butyrate, and to some extent propionate, serve as energy sources for the rumen epithelium and subsequently have the greatest impact on rumen epithelial development. Thus, the higher feed intake in Treatment 3 in this study justifies the increased empty rumen weight as well as the length, width, thickness, and density of the papillae.
Changes in body weight over different periods
Although Treatment 3 involved higher feed intake compared to Treatment 2, and consequently higher protein consumption, the ruminal ammonia concentration was greater in Treatment 2. Higher ammonia levels in the rumen of Treatment 2 indicate less microbial utilization and absorption of ammonia for recycling purposes. In addition to ammonia, branched-chain volatile fatty acids (BCVFA), which are indicators of protein fermentation in the rumen, were also highest in Treatment 2 calves. The lack of ammonia utilization or absorption in the rumen, likely due to inadequate development of this organ, leads to ammonia passing into the intestine. Correspondingly, calves in Treatment 2 exhibited a lower villus-to-crypt ratio in the duodenum, jejunum, and ileum compared to other groups.
CONCLUSIONS:
This study demonstrated that using steam-flaked corn combined with extruded soybean as the sole feed for calves can be considered an ideal diet. Replacing milk with this combination not only produces similar body weight results but also promotes better morphological development due to the fermentation of solid feed in the digestive tract, compared to feeding milk alone or simultaneously feeding milk and solid feed.
https://doi.org/10.2527/jas.20125731
REFERENCES:
Xie, X., et al., Effects of a mixture of steam-flaked corn and extruded soybeans on performance, ruminal development, ruminal fermentation, and intestinal absorptive capability in veal calves. Journal of animal science, 2013. 91(9): p. 4315-4321.