Effects Of Different Feeding Patterns On Growth And Digestive Tract Development In Preweaning Calves

Two different experiments were conducted to evaluate the effect of different feeding patterns (traditional and modern) on preweaning calves. It explored the effects of different feeding patterns on the average daily gain, body measurement indexes, feed nutrient digestive coefficient rumenal fermentation parameters, serum biochemistry indexes,enzyme activity of small intestine, rumen and duodenal growing developmental physiology indexes of holstein calves.Experiment 1 Forty-six Holstein calves (10 heifers+36 bulls) with the similar BW and birthday were selected and allotted randomly to two groups. Calves in groupⅠ(5 heifers+18 bulls) were fed in traditional feeding pattern (alfalfa hay+powder starter+milk). Calves in groupⅡ(5 heifers+18 bulls) were fed in the modern feeding pattern (pellet starter+milk). All the calves were weaned at 60d. The result indicated that dry matter intake (DMI) of groupⅠwas significantly higher than that of groupⅡ(P<0.05). Average daily gain (ADG), average height, average body length, average heart girth, and average circumference of cannon bone of calves was no significant different between the two feeding modes (P>0.05).The apparent digestibilities of crude protein (CP), Crude fat (EE) of the calves in groupⅡwere obviously higher 8.76% (P<0.05), 21.84% (P<0.05) than that of groupⅠ. The glucose and triglycerides contents were similar (P>0.05). At 45d and 60d, serum total protein content in groupⅡwas significantly higher 18.84% (P<0.05), 9.23% (P<0.05) than that of groupⅠ. Serum urea nitrogen content in groupⅠwas significantly higher 22.34% (P<0.05) than that of groupⅡat 45d. Lactate dehydrogenase (LDH) and alkline phosphatase (AKP) of serum was no significant different between the two feeding patterns. At 15d, serum glutamic-oxalacetic transaminease (AST) and lysonzyme (LZM) in groupⅡwas significantly higher 12.17% (P<0.05), 10.46% (P<0.05) than that of groupⅠ. Serum glutamate pyruvate transaminase (ALT) in groupⅡwas significantly higher 15.60% (P<0.05) than that of groupⅠat 30d. At 45d, the total antioxidant capacity (TOAC) in groupⅡwas significantly higher 8.44% (P<0.05) than that of groupⅠ. Serum NO and cortisol (CORT) of calves was no significant different between the two feeding modes (P>0.05), Serum IgG and IgM in groupⅡwas significantly higher 7.23% (P<0.05), 6.44% (P<0.05) than that of groupⅠat 30d. At 15d, serum T3, T4 in groupⅡwas significantly higher than that of groupⅠ(P<0.05). Serum growth hormone (GH) of calves was no significant different between the two feeding modes(P>0.05), At 30d and 45d, serum Insulin-like growth factor (IGF-1) in groupⅡwas significantly higher than that of groupⅠ(P<0.05). At 60d, serum interferon-γ(IFN-γ) in groupⅡwas significantly higher than that of groupⅠ(P<0.05). During the whole trial, diarrhea rate in groupⅡ(2.38%) was lower 23.47% than that of groupⅠ(3.11%).Experiment 2 Twenty-four Holstein bulls with the similar BW and birthday were selected and allotted randomly to two groups. Feeding patterns and trial period were same to the Experiment 1. The results indicated that the amylase activity in the middle jejunum in groupⅡwas significantly higher 36.74% (P<0.05) than that of groupⅠat 60d. In the underside jejunum in groupⅡwas significantly higher 10.68% (P<0.05), 11.19% (P<0.05) than that of groupⅠat 15d and 60d. The amylase activity in pancreas in groupⅡwas significantly higher 17.32% (P<0.05) than that of groupⅠa t 60d. At 60d, the chymotrypsin activity in duodenum, the foreside jejunum and the middle jejunum in groupⅡwas significantly higher 10.34% (P<0.05), 62.89% (P<0.05), 80.47% (P<0.05) than that of groupⅠ. At 30d and 60d, the chymotrypsin activity in the underside jejunum in groupⅡwas significantly higher 23.83% (P<0.05), 8.45% (P<0.05) than that of groupⅠ. The chymotrypsin activity in the pancreas in groupⅡwas significantly higher 19.69% (P<0.05), 7.67% (P<0.05) than that of groupⅠ. At 15d, 30d and 60d, the trypsase activity in duodenum in groupⅡwas significantly higher 144.30% (P<0.05), 26.31% (P<0.05), 48.80% (P<0.05) than that of groupⅠ. the trypsase activity in foreside jejunum in groupⅡwas significantly higher 99.40% (P<0.05), 38.17% (P<0.05), 216.22% (P<0.05) than that of groupⅠ. The trypsase activity in middle jejunum in groupⅡwas significantly higher 61.37% (P<0.05), 23.61% (P<0.05), 70.92% (P<0.05) than that of groupⅠ. The trypsase activity in pancreas in groupⅡwas significantly higher 84.48% (P<0.05), 73.06% (P<0.05), 116.30% (P<0.05) than that of groupⅠ. The lipase activity in the foreside jejunum in groupⅡwas significantly higher 27.43% than that of groupⅠat 15d (P<0.05). The lipase activity in middle jejunum in groupⅡwas significantly higher 43.33% (P<0.05), 74.24% (P<0.05) than that of groupⅠat 30d and 60d. The lipase activity in pancreas in groupⅡwas significantly higher 84.76% (P<0.05), 39.02% (P<0.05) than that of groupⅠat 30d and 60d. The lactase activity in duodenum in groupⅡwas significantly higher than that of groupⅠat 15d (P<0.05). The lactase activity in the foreside jejunum and underside jejunum in groupⅡwas significantly higher than that of groupⅠat 15d and 60d (P<0.05). The lactase activity in the middle jejunum in groupⅡw as significantly higher than that of groupⅠat 15d and 60d (P<0.05). Along with the growth of calves, the concentration of volatile fatty acids in the rumen has significant changes. The concentration of valerate in the rumen in groupⅡwas significantly higher 59.69% (P<0.05), 119.35% (P<0.05) than that of groupⅠat 30d and 60d. the concentration of acetate in the rumen in groupⅠwas significantly higher17.06% (P<0.05)%, 105.44% (P<0.05) than that of groupⅡat 30d and 60d. The concentration of propionate and butyrate in the rumen in groupⅡwas significantly higher 43.24% (P<0.05), 33.46% (P<0.05) than that of groupⅠat 60d. At 15d and 30d, the concentration of NH3-N in the rumen in groupⅠwas significantly higher than that of groupⅡ(P<0.05), the concentration of NH3-N in the rumen in groupⅡwas significantly higher than that of groupⅠat 60d (P<0.05). The protozoa in rumen of groupⅠwas significantly higher than that of groupⅡat 30d (P<0.05), but at 60d the protozoa in rumen of groupⅡwas significantly higher than that of groupⅠ(P<0.05). The thymus and pancreas relative proportion of groupⅡwas significantly higher than that of groupⅠat 30d (P<0.05). The splenic organ relative proportion of groupⅡwas significantly higher than that of groupⅠa t 30d (P<0.05). The cranial dorsal sac papillae and cranial ventral blind sac papilla number of unit rumen area in groupⅡwas more 20.14% (P<0.05), 21.82% (P<0.05) than that of groupⅠat 60d (P<0.05). The length of rumen papillaes in groupⅡwas higher than 52.68% (P<0.05), 22.25% (P<0.05) than that of groupⅠat 30d and 60d(P<0.05). The rumen, jejunum and duodenum villus development level in groupⅡwas better thanⅠgroup.In summary, modern pattern for preweaning calves could help to promote its rumen and reticulum development, strengthen the enzyme activity of intestinum tenue and pancreas, which was beneficial to the the balance of ruminal microbes region, increease the apparent digestibility, enhance immunity of calves, reduce the diarrhea rate and enhance the adaptation to the solid feed. Therefore, the modern pattern could decrease the costs of feeding.