Closure Of Oesophageal Groove Research Articles

Ultrasonographic examination of the oesophageal groove reflex in young calves under various feeding conditions.

The oesophageal groove reflex was examined in 6 milk-fed Holstein Friesian calves once weekly during the first 17 weeks of life. Additionally, the effect of different feeding methods (bucket, different nipple positions and openings), different milk temperatures (20, 30, 39, 45°C) and milk replacer concentrations (100, 125, 150 grams/litre of water) on oesophageal groove closure was investigated. The reticulum and abomasum were examined ultrasonographically using a 5.0-MHz convex transducer before, during and after feeding, and the oesophageal groove reflex was considered to be functional when milk was seen entering the abomasum during feeding. The reflex was consistently induced throughout the study period in all calves at all examinations and under all experimental conditions. However, it should not be assumed that feeding technique can be neglected in unweaned calves because suboptimal feeding management has been linked to various digestive disorders.

Fluoroscopic studies of the stimulatory effects of copper sulphate and cobalt sulphate on the oesophageal groove of sheep

Solid radiopaque markers were compared with barium sulphate suspension for the video-taped fluoroscopic investigation of oesophageal groove closure and forestomach bypass in recently-fed Romney hoggets. Oesophageal groove closure was clearly identifiable using both methods, although the 1.5 mm diameter solid markers showed a tendency to become lodged in the oesophageal groove and omasum, limiting their value for the study of forestomach bypass. Forestomach contractions, closure of the oesophageal groove and omasal function could be assessed using the solid radiopaque markers, which are potentially useful for studies of ruminant digestion. Ten ml of a 2% copper sulphate solution, when administered to the back of the oral pharynx 10 s before oral dosing, induced oesophageal groove closure in 55% (11 of 20) of the hoggets. Ten ml of a 2% cobalt sulphate solution had a similar effect (9 of 20), although the numbers of sheep investigated were too small for statistical comparison.

Effect of oesophageal groove closure on the pharmacokinetic behaviour and efficacy of oxfendazole in sheep

Direct intraabomasal oxfendazole (OFZ) administration resulted in the peak plasma OFZ concentration occurring sooner and the area under the plasma OFZ concentration curve being reduced when compared with intraruminal administration. Glucose given directly into the abomasum of fistulated sheep caused a substantially greater elevation of plasma glucose levels than did direct administration into the rumen. This difference was subsequently used to indicate rumen bypass, by oesophageal groove closure, after oral dosing with an OFZ formulation to which glucose had been added. When 17 penned sheep were drenched with OFZ containing added glucose, elevated plasma glucose levels indicated substantial rumen bypass in six of them and was negatively correlated with time to peak plasma OFZ concentration, area under the plasma OFZ curve and efficacy against thiabendazole resistant Haemonchus contortus. Among 60 grazing sheep there were indications of some degree of oesophageal groove closure in 42 per cent of them following drenching with OFZ and in these animals there was a significant reduction in OFZ efficiency as measured by faecal worm egg counts.

Effects of nipple or bucket feeding of milk-substitute on rumen by-pass and on rate of passage in calves

1. Effects of feeding liquid milk-substitute to young calves either by nipple-pail or open-bucket on the rumen by-pass and on the rate of passage were studied.2.Sixteen Holstein calves, aged 1 week initially, were used in three experiments in which calves were slaughtered after they were given liquids (milk-substitute and water) containing chromic oxide and SrCl2 6H2O as a tracer either by the nipple- or bucket-feeding method, and the distribution of tracers to the rumen, abomasum and the lower alimentary tracts was examined.3.When the liquid milk-substitute containing tracers was given by the nipple- or bucket-feeding method to calves having been trained to the corresponding procedures for the preceding 1 week, most of the tracers was directed into the omasum and abomasum. There seemed no difference in the functioning of oesophageal groove closure between the two feeding procedures. Even when the liquid milk-substitute containing tracers was given by the nipple-or bucket-feeding method to calves which had been accustomed to different procedures for the preceding week, the majority of tracers were found in the abomasum immediately after administration, though a slightly greater proportion of the tracers entered the reticulo-rumen.4.Continuing bucket feeding of liquid milk-substitute effected an efficient closure of the oesophageal groove at least up to 16 weeks of age. After calves were accustomed to consume liquid milk-substitute from the bucket from 1 to 4 weeks of age, drinking warm water from the bucket also caused efficient closure at least up to 16 weeks of age.When tracers were administered with warm water, Cr2O3 and strontium, especially the latter, transferred much more rapidly to the lower gut than when they were administered with liquid milk-substitute, probably reflecting the curd formation of the milk-substitute in the abomasum. When liquid milk-substitute with tracers was fed by the bucket-feeding method, Sr transferred more rapidly to the lower gut than when the milk-substitute was fed by the nipple-feeding method, indicating that the feeding procedure of liquid milk-substitute has an apparent effect on the rate of passage.

Effects of liquid feeding of concentrate from a pail on growth and on the digestibility of the diet in young calves.

1. Studies were done on the effects of giving calves two types of concentrate diet, both in a liquid form from an open pail or in a dry pelleted form, on the closure of oesophageal groove, body-weight gains and the digestibility of rations. 2. Twenty-four Holstein calves were used in an experiment by dividing into two groups of twelve calves each. The 'dry-fed' group (DFG) was given a pelleted concentrate, F1, from 25 to 42 d of age, and then given another type of pelleted concentrate, F2, from 43 to 87 d of age, and again given F1 from 88 to 112 d of age. The 'liquid-fed' group (LFG) was given from a pail a liquid suspension of the equivalent amount of the same concentrates as those fed to DFG calves, for the same periods. F1 contained skim milk and glucose with lower levels of maize and soya-bean meal than F2 which did not contain skim milk or glucose; F1 and F2 were both supplemented with 10 g methionine/kg and also supplemented with lysine at 5 and 10 g/kg respectively. All calves were allowed free access to roughage, and digestibilities were measured at 12 and 16 weeks of age. 3. Wet weights of reticulo-rumen and abomasal tissues (% whole stomach weight) were respectively 69.8 and 17.6 in DFG, and 59.0 and 26.4 in LFG at 42 d of age; at 87 d of age, the corresponding values were 68.0 and 16.3 in DFG, and 52.8 and 36.6 in LFG, and further, LFG had significantly more developed caecums and large intestines as well as significantly less developed reticulo-rumens and omasums than DFG. 4. Free amino acid patterns in plasma did not vary in DFG, but varied in LFG in response to the change in diet from F1 to F2 and to the difference between diets in lysine supplementation. 5. Feeding F1 in a liquid form and F2 in a dry form significantly improved calf gains. The intake of roughage in DFG exceeded that in LFG especially when F2 was fed. 6. The digestibility of diethyl ether extracts did not vary with feeding procedures, but that of crude protein (nitrogen x 6.25) was significantly higher in DFG independent of the type of diet. Digestibilities of dry matter and N-free extracts were significantly higher in LFG for F1, while higher in DFG for F2. The digestibility of acid-detergent fibre did not differ significantly between groups at 12 weeks of age, but was significantly higher in LFG at 16 weeks of age, suggesting a possible compensatory contribution of the large intestine to the digestion of fibre in LFG. 7. The efficiency of liquid feeding of a concentrate diet to ruminants compared with that of dry feeding is discussed.