. Cyclopedia of farm animals. Domestic animals; Animal products. PHYSIOLOGY OF DOMESTIC ANIMALS 19 The mechanism of rumination is as follows: A churning movement by the paunch forces the con- tents toward the orifice of the gullet. A deep inspiration followed by compression of the paunch by the diaphragm and the abdominal muscles forces the macerated contents of the paunch into the funnel-shaped orifice of the gullet, which cuts off a bolus and by reverse peristalsis conveys it into the mouth. The water-bag (second stomach) also shares in this contraction and supplies water to saturate the mas
. Cyclopedia of farm animals. Domestic animals; Animal products. PHYSIOLOGY OF DOMESTIC ANIMALS 19 The mechanism of rumination is as follows: A churning movement by the paunch forces the con- tents toward the orifice of the gullet. A deep inspiration followed by compression of the paunch by the diaphragm and the abdominal muscles forces the macerated contents of the paunch into the funnel-shaped orifice of the gullet, which cuts off a bolus and by reverse peristalsis conveys it into the mouth. The water-bag (second stomach) also shares in this contraction and supplies water to saturate the mass. After swallowing the second time, the bolus either passes into the rumen again or reaches the third stomach through the esophageal gutter. The formation of the bolus and its ascent require three seconds, mastication fifty seconds and the descent one and one-half seconds. A given amount of water in the rumen and a certain degree of dis- tention are necessary. After a meal cattle may not begin to ruminate unless watered. At least seven out of twenty-four hours are given to rumination. It is a voluntary act. " Losing the cud " is a myth. During sickness rumination ceases; when the appetite returns the cud returns of its own accord. This imaginary disease belongs to the same cate- gory as the "hollow horn" and "wolf in the ; All horned cattle, excepting the very young, nor- mally have hollow horns. Vomiting.—Vomiting is a reflex act caused by stimulation of the vomiting center in the brain, inducing spasmodic contraction of the stomach, diaphragm and abdominal muscles. The pig, dog and cat vomit readily; it is nature's method of relief. Cattle vomit infrequently, and horses only in extreme circumstances for the following rea- sons : (1) The esophagus, where it enters the stomach, has a thick and contracted wall. (2) There are spiral muscular fibers in its wall at this. Fig. 21. The stomach of a sheep. point. A stomach inflated artificially wi
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