Effect of orally administered cimetidine and ranitidine on abomasal luminal pH in clinically normal milk-fed calves.
OBJECTIVE
To characterize the change of pH in the abomasal lumen throughout a 24-hour period, to determine whether pH of the abomasal body differs from pH of the pyloric antrum, and to determine whether oral administration of cimetidine and ranitidine alters pH of the abomasal lumen in milk-fed calves.


METHODS
5 male dairy calves (4 Holsteins-Friesian, 1 Ayrshire), 5 to 15 days old.


METHODS
Cannulas were surgically positioned in the abomasal body and pyloric antrum of each calf. Calves received the following treatments in a randomized crossover design: milk replacer (60 ml/kg of body weight, q 12 h [untreated control calves]), milk replacer and cimetidine (50 or 100 mg/kg, q 8 h), or milk replacer and ranitidine (10 or 50 mg/kg, q 8 h). The pH of the abomasal body and pyloric antrum was measured for 24 hours, using miniature glass pH electrodes.


RESULTS
Suckling of milk replacer immediately increased abomasal luminal pH from 1.4 to 6.0, followed by a gradual decrease to preprandial values by 6 hours. Preprandial and postprandial pH values were not significantly different between the abomasal body and pyloric antrum, indicating lack of pH compartmentalization in the abomasum of milk-fed calves. Administration of cimetidine and ranitidine caused a significant dose-dependent increase in mean 24-hour abomasal luminal pH.


CONCLUSIONS
Abomasal acid secretion in milk-fed calves is mediated in part by histamine type-2 receptors. Cimetidine and ranitidine may be efficacious in the treatment of abomasal ulcers in milk-fed calves.
Ahmed
A F
AF
Faculty of Veterinary Medicine, Assiut University, Egypt.
Constable
P D
PD
Misk
N A
NA
D000018:Abomasum / Q000187:drug effects* / Q000378:metabolism; D000284:Administration, Oral; D000818:Animals; D000831:Animals, Newborn; D002417:Cattle / Q000378:metabolism*; D002927:Cimetidine / Q000008:administration & dosage / Q000494:pharmacology*; D018592:Cross-Over Studies; D006635:Histamine H2 Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D008297:Male; D008892:Milk / Q000378:metabolism*; D011706:Pyloric Antrum / Q000187:drug effects; D011897:Random Allocation; D011899:Ranitidine / Q000008:administration & dosage / Q000494:pharmacology*
D006635:Histamine H2 Antagonists; D002927:Cimetidine; D011899:Ranitidine