B. Atony of the Forestomachs

Affected animals usually show a pronounced fall in milk yield caused probably by the sharp fall in volatile fatty acid pro­duction in the atonic rumen. Rumen contractions appear to play the same role as hunger contractions in simple stomachs and the decreased food intake is probably due to the ruminal atony.

Clinical Findings. A reduction in appetite is the first sign and is followed clo­sely in milking cows by a slight drop in milk production. Both occur suddenly, the anorexia may be partial or complete but the fall in milk yield is relatively slight. The animal's posture is unaffected but there is mild depression and dullness. Rumi­nation ceases and there is constipation with scanty, firm feces in most cases although diarrhea may occur on damaged feeds. Ruminal movements are depressed in frequency and force or are absent. There may be moderate tympany, especially with frozen and damaged feeds or in allergy but the usual finding is a firm doughy rumen without obvious distension.

There is no systemic reaction and the pulse, temperature and respiration rates are unaffected. Pain cannot be elicited by percussion of the abdominal wall. Most cases recover spontaneously or with simple treatments in about 48 hours. The disease is not a fatal one.

Secondary ruminal atony occurs in many diseases especially when septicemia or toxemia is present but there are usually additional clinical signs to indicate their presence.

Exercise 4. Read and translate the text B, determine the verb forms and their function and retell in English according next questions:

1 Какова причина резкого снижения молочной продуктивности­ у больных животных?

2 Какие симптомы характерны для атонии преджелудков?

3 Наблюдаются ли изменения в пульсе и температуре при
этом заболевании?

4 Часто ли заболевание приводит к смерти животного?

5 В каких случаях развивается вторичная атония рубца?

Lesson 16