Oesophageal Groove Reflex 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.

Estimation of milk leakage into the rumen of milk-fed calves through an indirect and repeatable method

In milk-fed calves, quantification of the milk that enters the rumen (ruminal milk volume, RMV) because of malfunction of the esophageal groove reflex may explain part of the variability observed between animals in their growth performance. The RMV can directly be quantified by adding an indigestible marker to the diet and measuring its recovery in the rumen at slaughter, but this technique cannot be repeated in time in the same animal. The objective of the study was to evaluate three indirect methods for estimating RMV. The first method was based on the assumption that ruminal drinking delays and limits acetaminophen appearance in blood after ingestion of milk supplemented with acetaminophen. The second method was based on a negative linear relationship between RMV and urinary recovery of non-metabolizable monosaccharides (3-O-methylglucose, l-rhamnose and d-xylose) added to the milk, owing to rumen fermentation. In the third method, RMV was calculated as the difference between total milk intake and the increase in abomasal milk volume (AMV) at feeding, measured through ultrasonography shortly after feeding, or estimated from the mathematical extrapolation of AMV to feeding time, based on consecutive measurements. These methods were tested in three experiments where calves (n=22, 10 and 13) were bucket fed or partly tube fed (i.e. by inserting milk replacer into the rumen via a tube to mimic ruminal drinking). In addition, Co-EDTA and Cr-EDTA were used as an indigestible marker in one experiment to trace bucket-fed or tube-fed milk replacer, respectively, to measure RMV. The relationship between AMV measured by ultrasonography and AMV measured at slaughter improved when kinetics of AMV were extrapolated to the time of slaughter by mathematical modeling (error between predicted and measured AMV equaled 0.49 l). With this technique, RMV during feeding averaged 17% and 24% of intake in Experiments 2 and 3, respectively. Plasma acetaminophen kinetics and recovery of non-metabolizable monosaccharides in urine were partly associated with ruminal drinking, but these techniques are not considered quantitatively accurate without further information of rumen degradation and absorption. The recovery of indigestible marker measured at slaughter gave a quantitative estimate of RMV (2% in Experiment 3), but improper measurement of emptying rate of fluid from the rumen may lead to underestimation. In conclusion, measuring changes in AMV by ultrasonography, in response to milk feeding, was the most promising indirect method to quantify RMV in veal calves.

In vivo assessment of the ability of condensed tannins to interfere with the digestibility of plant protein in sheep

To assess the effect of condensed tannin (CT) astringency on the digestibility of protein post-ruminally, CT were purified from four types (accessions) of Mulga ( Acacia aneura), and a Leucaena pallida and dosed into sheep as complexes with 15N-plant protein (tannin–protein complexes, TPC), together with an indigestible marker, chromium-EDTA (Cr-EDTA). Each CT treatment dose comprised 12 mg CT, 10 mg 15N-protein, and 2.77 mg of Cr. A protein-only control (same as the other TPC solutions but without any CT) treatment was also included to make a total of six treatments. Treatments were applied in two 6 × 6 Latin Square designs with 72 h between each infusion for each sheep. In the first, the solutions were infused post-ruminally via an abomasal cannula. In the second they were dosed directly into the mouth following an intra-nasal dose of an analogue of vasopressin in an attempt to stimulate the oesophageal groove reflex to direct the solutions more efficiently toward the small intestine. Results showed no detectable effect of CT type on the in vivo digestibility of the 15N-protein. Protein digestibilities were uniformly high, indicative of complete dissociation of the TPC. There was no correlation between protein digestibility, mouth to faeces, and protein digestibility, abomasum to faeces ( P > 0.05). In vivo digestibility was also uncorrelated with CT astringencies defined in vitro ( P > 0.05). Astringency in vitro was defined as the mg of CT required to achieve half-maximal precipitation of 0.5 mg of protein (bovine serum albumin). In vitro, the most astringent CT ( A. aneura 883558), had at least 1.6 times the astringency of the weakest CT, ( A. aneura 842394). The A. aneura with the weakest CT also contained less than 1/3 the total amount of CT/g leaf dry matter than that with the strongest, highlighting the scope for selection of more nutritionally useful types of A. aneura. Limitations of the in vivo protocol used are discussed and it is concluded that the effect of CT astringency on the availability of protein post-ruminally is minimal.

Colostrum management in calves: effects of drenching vs. bottle feeding

The objective was to examine whether the administration of colostrum by a drencher is a safe method to achieve satisfying immunoglobulin concentrations in newborn Holstein Friesian (HF)-calves. Twenty-one calves were fed 1 h postnatum with 2 l colostrum from their dam using a nipple bottle (group I); 15 calves were drenched with 4 l colostrum from their dam 1 h postnatum (group II). Thereafter, all calves were fed milk replacer exclusively. Serum concentration of total immunoglobulin [analysed by Sandwich-enzyme-linked immunosorbent assay (ELISA)] 24 h postnatum was higher in drenched calves (25.2 g/l; 12.8/52.2; median and 10/90 percentiles) compared with bottle-fed calves (14.1 g/l; 9.2/24.7). To characterize the kinetics of immunoglobulin absorption, 17 blood samples were taken frequently within 72 h postnatum using a jugular catheter in five calves fed 2 l colostrum by nipple bottle and five calves drenched with 4 l colostrum 1 h postnatum. A slightly delayed increase of serum immunoglobulin concentration (approximately 3 h) was obvious in drenched calves compared with bottle-fed calves, but drenched calves reached significantly higher immunoglobulin concentrations compared with bottle-fed calves. It is concluded that the proper application of colostrum by a drencher is a useful method for adequate colostral supply in newborn calves. The failure of the oesophageal groove reflex in drenched calves caused no clinical consequences.

Alimentação de bezerros ruminantes com dieta sólida ou líquida, via goteira esofageana: formação da goteira e escape ruminal

Efeitos da alimentação de proteína texturizada de soja (PTS), fornecida tanto na forma líquida (via goteira esofageana) como sólida (via concentrados), foram estudados em um delineamento em quadrado latino 4 x 4. Quatro novilhos da raça Holandês dotados de cânulas ruminais e com 100 kg de peso ao início do experimento, foram empregados para avaliar proteína texturizada de soja fornecida em quatro níveis crescentes na forma líquida 0/0, 1/3, 2/3 e 3/3, oferecida em mamadeira, conjuntamente com níveis decrescentes de PTS na mistura concentrada de forma a manter o mesmo nível de proteína na dieta. Os subperíodos experimentais contaram 21 dias, sendo os dezesseis primeiros para adaptação à dieta, constituída de feno de coast-cross (Cynodon dactylon), mistura concentrada e porção líquida. No vigésimo dia foi colhido material para análise de N-NH3 do líquido ruminal,bem como controle do pH, às 0, 2, 3, 4, 5 e 6 h após a primeira refeição. Também foi estimada a eficiência de formação da goteira esofageana com o emprego de marcador de fase líquida polietilenoglicol (PEG), colhido diretamente do rúmen. O reflexo da formação da goteira esofageana foi mais eficiente no tratamento de mais alto nível de suplemento protéico líquido mostrando menores concentrações de PEG no rúmen. As medições de nitrogênio amoniacal concordaram com essa observação, pois houve decréscimo em sua concentração com o aumento do nível de suplementação líquida. Não ocorreram efeitos da forma de suplementação protéica sobre os ganhos de peso dos bezerros.

Time course of changes in the fatty acid composition of plasma in the milk fed pre-ruminant calf supplemented with a palm/rapeseed oil mixture or fish oil

In pre-ruminant calves the oesophageal groove reflex allows milk to bypass the developing rumen and is a mechanism by which dietary fatty acids can be delivered directly to the small intestine. This experiment was a pilot study carried out to establish the extent and time course of the changes in plasma fatty acid composition in calves fed milk supplemented with oils of differing fatty acid composition and allowed minimal access to roughage (straw bedding). The work was carried out to provide baseline data for a longer study with calves in which rumen development will be encouraged by feeding solid food but the oesophageal groove reflex will be maintained through long term milk feeding and used as a means of delivering polyunsaturated fatty acids (PUFA) directly to the small intestine.

尿中アラントイン排泄量に及ぼす飼料由来核酸の影響

The objective of this experiment was to evaluate the contribution of dietary nucleic acids to the urinary allantoin excretion. Four Japnaese Saanen kids, which were daily given cow's milk to maintain esophageal groove reflex, were used. The experiment consisted of 3 consecutive periods of 7 days each. In the 1st period, they were given a hay wafer, a concentrate mixture and cow's milk. In the 2nd period, they were given Tolura yeast dispersing with cow's milk as the source of nucleic acids (nucleic acids content: 11.0%, purine base content: 176μmole/g). It was assumed that all of the yeast was rumen-bypassed by esophageal reflex. In the 3rd period, the yeast was given as the dry diet. All of the ingested yeast was assumed to enter the rumen. During the last 5 days of each period, total urine was collected daily, and allantoin was determined. Daily urinary allantoin excretions (mmole/day) were 2.50, 6.32 and 4.42 for periods 1, 2 and 3, respectively. From these results, it was assumed that of the nucleic acids ingested as dry diet, over 45% was not degradaded in the rumen. It was considered that sometimes dietary nucleic acids may have a considerble effect on the urinary allantoin excretion.

Oesophageal groove dysfunction as a complication of neonatal diarrhea in the calf

In a study of 249 calves up to 2 weeks of age, with acute catarrhal enteritis, disturbance of the oesophageal groove contraction was demonstrated in 28 (11.2%) calves, 11 of which died, and was suspected in a further 29 (11.6%), 12 of which died. In 37 calves with oesophageal groove disturbance (30 with neonatal diarrhoea, 7 with other disorders), the acid status of the rumen was examined several times. The following types of fermentation were detected: (1) predominant butyric acid fermentation; (2) predominant lactic acid fermentation; (3) biphasic (type 1 changing to type 2, or vice versa). In milk fed calves with neonatal diarrhoea, oesophageal groove reflex dysfunction can be the cause of a fatal outcome and should be considered during clinical examination.

THE EFFECTS OF WEANING SCHEDULE, DURATION OF MILK FEEDING AND FISHMEAL ON CALF PERFORMANCE

Two experiments were conducted to measure the effects of weaning procedure and duration of milk feeding on calf performance and overall milk consumption. In exp. 1, compared with calves weaned when consuming 500 g d−1 of starter (control), those weaned when intake reached 1000 gd−1 (delayed) consumed 2.5 times as much milk and those fed gradually diminishing milk levels until weaned at 1500 g d−1 of starter intake (gradual) consumed about 1.5 times as much milk. Both the control and delayed groups experienced a growth setback of up to 8 d at weaning. There was no change in growth rate for the gradual weaning group. In exp. 2, the calves were gradually weaned over 7 d commencing at 28 d of age and were fed either supplemental milk, wet fishmeal, dry fishmeal or no protein supplement (control) for an additional 140 d. Calves fed milk grew fastest and had the best feed:gain ratio (P < 0.01). Those fed fishmeal grew faster than the controls and had better feed:gain ratios (P < 0.01). There was no difference between the wet and dry fishmeal suggesting that any increased rumen by-pass through the esophageal groove reflex did not result in improved animal gain. The potential value to the producer of feeding over quota milk to calves marketed at 168 d was calculated to be $15.22 hL−1 on the basis of dry feed replaced and increased weight gain by the milk-fed calves. Key words: Calves, milk, weaning, by-pass protein, fishmeal

The failure of the oesophageal groove reflex, when fluids are given with an oesophageal feeder to newborn and young calves.

The fate of colostrum and other fluids given with an oesophageal feeder was studied in newborn calves and in young calves up to 3 weeks by means of radiological techniques. Any fluid given with an oesophageal feeder was found in the forestomachs, since it apparently did not induce an oesophageal groove reflex. Also when suckling was induced during feeding with the oesophageal feeder, the oesophageal groove reflex did not occur. The outflow of colostrum and other fluids from the forestomachs to the abomasum and small intestine occurred for the most part within 3 hours. Only the emptying of the ventral ruminal sac was sometimes delayed for 24 or 48 hours. The results obtained in calves up to 3 weeks old did not differ from those obtained in newborn calves. It was concluded that although colostrum given by oesophageal feeder entered the forestomachs, the rapid flow to the abomasum and small intestine created the conditions for a sufficient absorption of immunoglobulins. Application of colostrum with an oesophageal feeder in newborn calves promises to be a timesaving and effective method for creating an optimum passive immunity of the calves.

Feeding Cholesterol and Tallow in Liquid Diets to Veal Calves

Thirty-six Holstein bull calves were raised to 16 wk on five liquid diets containing skim milk plus either 3.5% milk fat, 3.5% tallow, 3.5% tallow and .2% cholesterol, 7.0% tallow, or 7.0% tallow and .2% cholesterol. Diets were fed at 10% of body weight by nipple pail to preserve the esophageal groove reflex. Intakes of dry matter, gains of body weight, and feed refusals were greater for calves fed 7.0% tallow. Concentrations of lipid and cholesterol in blood plasma increased markedly (2 to 3 times) in calves fed cholesterol. Thyroxine and triiodothyronine concentrations in plasma were highest in calves showing the most growth response. Weight of liver was elevated both by feeding high tallow and by feeding cholesterol. Liver fat was elevated more by feeding .2% cholesterol than by doubling dietary fat. Yield of trimmed veal was 14% greater when diets included cholesterol and 7.0% tallow or 7.0% tallow than when they were 3.5% tallow or milk fat. Feeding liquid tallow can be successful in veal production when ingredient costs are advantageous. Economics of ingredient selection is discussed. Further research utilizing different concentrations of tallow and higher intake is needed.

The functioning of the oesophageal groove reflex and comparison of the performance of lambs fed individually and in groups.

1. Two experiments involving 106 lambs were conducted to study the functioning of the oesophageal groove reflex in lambs sucking from either individual feeders or from a bulk dispenser. The effects on the performance of lambs given either a high-protein or a low-protein creep feed in conjunction with either a ewe's milk substitute, Ewelac, or a homogenate of calcium caseinate, Casilan, were studied. Two milk substitutes, one with a long and one with a short clotting time were compared in terms of their effects on the incidence of diarrhoea.2. The location of the liquid feeds in the stomach was studied radiologically.3. In both experiments the sucking behaviour of the lambs was closely related to thefunctioning of the oesophageal groove reflex and performance of the lambs. In the first experi-ment the milk substitute consistently entered the abomasum in seven of the ten individually fed lambs and in twelve of the twenty-two group-fed lambs. The corresponding figures for the second experiment were twenty-two of the twenty-four individually fed and thirty-four of the fifty group-fed lambs.4. When the milk substitute entered the abomasum it always did so throughout the fattening period even in those instances where the milk had been withheld for 1 month.5. Poor sucking, low milk consumption and the entry of the milk into the rumen resulted in very poor performance by the lambs. Such lambs demonstrated a non-specific unthriftiness similar to the ‘tail enders’ sometimes observed with lambs reared with ewes.6. Continued feeding with either the milk substitute or casein homogenate with a low-protein creep feed did not improve performance.7. The clotting time of the milk substitute did not appear to influence the incidence of diarrhoea among the lambs.

Studies on the oesophageal groove reflex in sheep and on the potential use of the groove to prevent the fermentation of food in the rumen.

1. Fluids were given by mouth in various ways to young sheep. The extent to which closure of the oesophageal groove operated to direct the fluid to the abomasum was assessed by radiography.2. Salt solutions and milk given as a drench did not produce complete closure of the groove. However, when the animals were accustomed to sucking from a teat before weaning, any liquid suspension and also water, sucked from a bottle, passed entirely to the abomasum even in 12-month-old sheep.3. This technique may be useful when it is desirable to cause protein or other nutrients to by-pass fermentation in the rumen.

Studies on the Alterations In Blood Sugar and Rumen Fluid Following Peroral Administration of Readily Available Carbohydrates to Dairy Cows

After peroral administration of 10 % NaHCO3 solution + glucose the rise in blood sugar was greater than after glucose alone. This indicates that the oesophageal groove reflex can be released also in adult cattle. By this means part of the glucose administered probably passed direct to the abomasum — small intestine without first being converted into volatile fatty acids in the rumen. The blood sugar rise was diphasic, the first coming after 1 and 2 hrs. and the second after 12 and 24 hrs. Six hrs. after the ration there was no rise. After administration of NaHCO3 + fructose most of the cows had severe diarrhoea and the blood sugar value was unaffected. The changes in composition of the rumen fluid after NaHGO3 + glucose and after NaHCO3 + fructose were similar with the exception that the rumen pH was lower after the fructose ration. In another experiment a comparison was made between the effects on blood sugar level and rumen fluid of molasses (saccharose) and whey (lactose) administered perorally. Molasses caused a manifest rise in blood sugar 6, 12 and 24 hrs. after the administration, whereas after whey the blood sugar level had risen only slightly at the same time. The molasses were quickly converted in the rumen, and the molar proportions of the volatile fatty acids formed were unaffected. The whey was broken down considerably more slowly and under formation of considerably more HAc and HBu than in the case of molasses. This is interpreted in the manner that the whey concentrate used should have a potentially positive effect on the milk fat content.