The effects of corn silage diets on intestinal morphology in dairy calves

Abstract Text: A calf’s diet in the first few weeks of life is critical for gastrointestinal tract development. Current feed prices are causing producers to experiment with less expensive alternatives. These different feeds may affect the development of the gastrointestinal tract which can further affect feed efficiency and calf performance.  Therefore, evaluating intestinal morphology is an indicator of how well the animal is absorbing nutrients. The objective of the study was to determine the post-weaning effects of calf starter and corn silage fed to pre-weaned dairy calves on jejunal morphology.  A total of 45 calves (n=15/trmt) were fed a diet of whole milk with one of the following treatments: 100% calf starter (C), 60% calf starter and 40% corn silage (CC), or 100% corn silage (CS). Nine calves were sacrificed 8 weeks after birth. Jejunal samples were collected to compare between the three treatment groups. Samples were preserved in formalin and later phosphate buffered saline until further analysis. Using a cryo-microtome, slices of tissue were made into nine slides per calf, and stained with methylene blue. Pictures were taken with a compound light microscope and measured using the ImageJ computer program (NIH, Bethesda, MD). Measurements were recorded including villi length, crypt depth, and villi width. Measurements were averaged per section block and were statistically analyzed using the Mixed Procedure in SAS 9.2.  Significance was determined at P<0.05 and trends at P<0.15.  Least squares means of villi lengths were 97.65, 105.61, and 89.57 um for treatments C, CC, and CS, respectively (P=0.12).  Least squares means of crypt depths were 46.10, 48.58, and 38.69 um for treatments C, CC, and CS, respectively (P=0.03) and villi diameters were 14.51, 15.38, and 17.17 um for treatments C, CC, and CS, respectively (P=0.69).  Results from the study indicated that the calves fed CS had significantly shorter crypt depths and tended to have shorter villi lengths compared with the other treatments.  This may indicate better intestinal development in calves fed either 100% calf starter or a mix of 60% calf starter and 40% corn silage.

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Keywords: calves, corn silage, intestine