Abstract: The dynamics of the intraruminal and intraabomasal pH in adult goats and cows was compared 15 min before and seven hours after unlimited hay and concentrated mixed feed based on barley, wheat and sunflower meal (goats – 0.5 kg and bulls - 2 kg) feeding. Five bulls (n=5) in the age of 1.5 and one year old goats (n=5) were included in this study. To investigate the changes of reaction of abomasum and rumen in animals before and after feeding, the uninterrupted long-lasting intragastric pH measurement method was applied together with a chronic fistula method. For the purposes of intraruminal and intraabomasal pH measurements a special pH-meter for two measurements. In conclusion it was established that in case of adult bulls pH did not significantly changed in rumen and abomasum after the feeding of the concentrated mixes feed and hay, but in case of goats pH level in the rumen and abomasum after the similar feeding decreased significantly during the two hours’ period. Thereby these functional processes in rumen and abomasum are different in these ruminants. The established pH indicators in various parts of abomasum of adult bulls and kids after feeding of hay can differ considerably, therefore upon establishing the pH value it is important to indicate its location as precisely as possible. For goats this difference is not significant.