Search

This study was designed to determine the rumen outflow of fatty acids (FA) and biohydrogenation (BH) extent using alternative sampling sites (reticulum and omasum) to abomasum in dry cows fed different sources of FA. Four Holstein non-pregnant dry cows (≥3 parturitions, and 712 ± 125 kg BW), cannulated in the rumen and abomasum, were randomly assigned to a 4 × 4 Latin square design experiment, containing the following treatments: 1) control (CON); 2) soya bean oil (SO), dietary inclusion at 30 g/kg; 3) whole raw soya beans (WS), dietary inclusion at 160 g/kg; and 4) calcium salts of FA (CSFA), dietary inclusion at 32 g/kg. Rumen outflow of nutrients was estimated using the three markers reconstitution system (cobalt-EDTA, ytterbium chloride, and indigestible neutral detergent fibre [NDF]). Diets with FA sources decreased feed intake and increased FA intake. No differences in nutrient intake and digestibility were detected among cows fed diets supplemented with different FA sources. Diets with FA sources reduced the rumen outflow of DM and NDF, hence decreasing their passage rates. In addition, SO diet reduced the ruminal outflow of DM and NDF in comparison with WS and CSFA. Omasal sampling yielded the highest values of rumen outflow of NDF and potentially degradable NDF (pdNDF), whereas the reticular and abomasal samplings yielded intermediate and least values, respectively. The interaction effect between diet and sampling site was observed for rumen outflow of majority FA (except for C16:0, C18:0, and C18:2 trans-10, cis-12) and BH extension of C18:1 cis, C18:2, and C18:3. Calculations derived from abomasal sampling revealed that WS and CSFA diets had lower BH extent of C18:1 cis and C18:2 in comparison with SO, whereas cows fed CSFA had greater BH extent of C18:3 and lower BH extent of C18:1 cis compared to those fed WS. However, the latter results were not similar when calculations were performed based on the reticular and omasal samplings. Thus, there is evidence that neither reticular nor omasal samplings are suitable for estimating rumen outflow of FA in dry cows. In addition, WS and CSFA diets can increase the abomasal flow of polyunsaturated FA in dry cows.

Several manufacturers recommend to feed mixture comprising equal amounts of oral rehydration salt (ORS) solution and milk for diarrheic calves after milk withdrawal. Such a feeding method is expected to supply more nutrients and energy compared to feeding only the ORS solution. However, little is known about the effects of feeding milk diluted with ORS solution on calves' digestive process. This study examined the abomasal contents, volumes, and emptying rates in calves fed whole milk, milk diluted by 50% with ORS solution (50% ORS-milk), and ORS solution. Ultrasonography identified curds in the milk-fed calves, but not in the 50% ORS-milk-fed or the ORS-fed calves. The abomasal fluid of the 50% ORS-milk-fed calves contained not only β-lactoglobulin but also α-casein (CN), β-CN, and κ-CN, which were used for curd formation and undetectable in the milk-fed calves. Abomasal pH was relatively higher in the 50% ORS-milk-fed than that in the milk-fed calves. Abomasal emptying rates were significantly faster in the ORS-fed than in the 50% ORS-milk-fed and the milk-fed calves. These data indicate that the formation of abomasal curd is inhibited in the 50% ORS-milk-fed calves due to the resultant high abomasal pH and low κ-CN concentration. The 50% ORS-milk may not provide rehydration as quickly as the ORS solution. In conclusion, we do not recommend feeding 50% ORS-milk to calves.

The objective of this study was to determine if feeding colostrum to newborn calves through an esophageal tube, compared with a nipple bottle, would delay abomasal emptying, which would in turn decrease passive transfer of IgG and plasma glucose, insulin, and glucagon-like peptide (GLP) 1 and GLP-2 concentrations. Twenty newborn Holstein bull calves were fed 3 L of colostrum replacer (200 g of IgG) through either an esophageal tube or nipple bottle at 2 h after birth followed by feeding pooled whole milk every 12 h after birth. Acetaminophen was mixed into the colostrum meal as a marker for abomasal emptying. A jugular catheter was inserted 1 h after birth and blood was sampled frequently to analyze serum for IgG and acetaminophen and plasma for glucose, insulin, GLP-1, and GLP-2. Feeding method did not affect abomasal emptying, and as a result no treatment effect was present on serum IgG concentrations. Maximum concentration of serum IgG was 24.4 ± 0.40 mg/mL (± standard error), which was reached at 14.6 ± 1.88 h after the colostrum meal for both groups. Apparent efficiency of absorption at maximum concentration of IgG was 52.9%, indicating high efficiency of passive transfer of IgG for both treatments. Tube feeding increased glucose and insulin area under the curve before the first milk meal, most likely due to the decreased time to consume the colostrum meal. In addition, tube-fed calves consumed 0.5 ± 0.13 L more milk in their first milk meal than bottle-fed calves. No treatment effect on plasma concentrations of GLP-1 or GLP-2 was present, but both hormones increased after colostrum feeding. These findings confirm that there is no effect on absorption of IgG from colostrum when feeding good-quality colostrum at a volume of 3 L through either an esophageal tube or nipple bottle., (Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Effects of continuous isomolar infusions of acetic acid (AcA) or sodium acetate (NAc) infused into the rumen (RU) or into the abomasum (AB) on feeding behavior, dry matter intake (DMI), and metabolic response of cows in the early postpartum period were evaluated. Six rumen-cannulated multiparous Holstein cows (11.8 ± 3.9 d in milk; mean ± SD) were utilized in a 6 × 6 Latin square design experiment balanced for carryover effects with a 2 × 3 factorial arrangement of treatments. Treatments were AcA and NAc, with sodium chloride (CON) as a control, infused at a rate of ˜0.75 mol/h (0.5 L/h) into the RU or AB for the first 8 h following feeding, with a rest day between infusion days. Treatment sequences were assigned randomly to cows. Feeding behavior was recorded by a computerized data acquisition system and blood was sampled at 0, 4, and 8 h relative to the start of infusion. We hypothesized that AcA is more hypophagic than NAc, and that infusion into the AB is more hypophagic than infusion into the RU. Dry matter intakes (DMI) for the CON treatments were similar at 6.2 kg/8 h for RU and 6.1 kg/8 h for AB, and the AcA and NAc treatments interacted with site of infusion to affect DMI. The NAc-RU treatment did not reduce DMI (7.0 kg/8 h), whereas AcA-RU (2.6 kg/8 h), AcA-AB (3.7 kg/8 h), and NAc-AB (4.0 kg/8 h) decreased DMI compared with CON. Following infusions of AcA compared with NAc, there was a residual effect on DMI for the remainder of the day, but treatments did not affect DMI during the rest day. Treatments increased plasma acetate and β-hydroxybutyrate concentrations over time (interaction) and decreased plasma insulin concentration compared with CON. Plasma glucose concentration decreased over time after AcA-AB infusion compared with other treatments and CON. Plasma nonesterified fatty acid concentration increased over time for AcA compared with NAc and CON, suggesting an increase in lipolysis to compensate the decrease in DMI. In contrast to the other treatments, NAc-RU did not decrease DMI compared with control but we cannot determine the reason for this from the data available from the current study., (Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to determine the time course for adaptation of the reticulo-rumen, omasum, abomasum, and small intestine in response to an abrupt increase in the proportion of grain in the diet. Adaptive responses include tissue and digesta mass, small intestinal length, and brush border enzyme activity in the duodenum, proximal jejunum, and ileum. Twenty-five Holstein steers (213 ± 23 kg; 5 to 7 mo of age) were blocked by body weight, and within block were randomly assigned to 1 of 5 treatments: the control diet (CTRL; 92% chopped grass hay and 8% mineral and vitamin supplement on a dry matter basis) or a moderate grain diet (MGD; 50% chopped grass hay, 42% rolled barley grain, and 8% mineral and vitamin supplement) that was fed for 3 (MGD3), 7 (MGD7), 14 (MGD14), or 21 d (MGD21). Dry matter intake was limited to 2.25% of body weight to ensure that changes in dry matter intake did not confound the results. On the last day of the dietary exposure, steers were slaughtered 2 h after feeding. Reticulo-rumen tissue mass and ruminal epithelium mass in the ventral sac of the rumen were not affected by the MGD. Wet reticulo-ruminal digesta mass decreased from CTRL to MGD7 and then increased, but reticulo-ruminal digesta dry matter mass did not differ between treatments. Omasal mass, omasal tissue mass, and omasum digesta mass decreased linearly with the number of days fed MGD, but abomasal tissue mass tended to increase linearly. Duodenal tissue mass tended to increase linearly, and ileal length increased linearly with the number of days fed MGD. Lactase activity in the proximal jejunum increased linearly and maltase activity in duodenum tended to increase linearly with days fed MGD. Aminopeptidase N activity in the proximal jejunum increased cubically with days fed MGD, and dipeptidylpeptidase IV activity in ileum tended to decrease from CTRL to MGD14 and then tended to increase. Adaptation to a diet with a greater proportion of concentrate involves changes in the mass and length of regions of the gastrointestinal tract and brush border enzyme activity. These changes take place gradually over at least 3 wk., (Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Elevated planes of nutrition in the preweaning period of dairy calf management can increase average daily gain, shorten age at puberty, and increase milk yield. In a previous study, 12 Holstein calves were fed 2 meals/d of 4 or 2 L milk replacer up to 7 wk of age. The objective of the current study was to estimate parameters of abomasal emptying and glucose-insulin dynamics in these calves by fitting a mechanistic model to postprandial appearances of plasma glucose, insulin, and the abomasal emptying marker acetaminophen measured at 4 and 7 wk of age. Higher intake of milk replacer resulted in longer bouts of abomasal emptying at a slower rate. Parameters of glucose and insulin dynamics were not affected by milk replacer intake. However, older calves had decreased insulin-stimulated glucose utilization indicating impaired insulin sensitivity, as well as increased pancreatic responsiveness. Neither of these effects were apparent from i.v. glucose tolerance tests on the calves and may have been related to postprandial gut hormone release. Effects of age on parameters of glucose-insulin dynamics were larger than effects of milk replacer intake. Conversely, effects of milk replacer intake on abomasal emptying were larger than effects of age., (Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Creating the ideal nutrition program for calves is a demanding task that has undergone tremendous change in recent years. Products and technologies including novel milk replacers and automated calf feeding systems have been developed to facilitate the ability of dairy producers to feed for higher growth rates before weaning. The creation of new feeding programs and milk replacers has to be looked at carefully, not only from a nutrition point of view but also from the perspective of a potential effect on physiologic digestion and calf health. Abomasal emptying is a critical factor that may link nutrition and disease. The purpose of this article is to review both intrinsic and extrinsic factors that are responsible for abomasal emptying. Predominant extrinsic factors controlling abomasal emptying include meal volume, energy density, and osmolality along with the content and source of protein. This article also reviews experimental methods used to measure abomasal emptying in the calf including those that would be appropriate for use under field conditions. Among these methods, the use of ultrasonography and different absorption tests (d-xylose, acetaminophen) as tools to measure abomasal emptying are discussed. The relationship between abomasal emptying and disease is explored, particularly as it relates to abomasal bloat. Abomasal bloat is a complex syndrome that seems to be increasing in frequency and whose etiology likely at least partially involves slowing of abomasal emptying. Suggestions for minimizing the effect of feeding programs on abomasal emptying are explored as well as needs for future research., (Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The aim of the research was to determine the relationship between the acidity and temperature of the contents of the reticulorumen and abomasum in the first 10 days after calving and to evaluate these factors as predictive traits for the diagnosis of subclinical acidosis. The acidity and temperature of the contents of the reticulorumen and abomasum were measured using specific smaXtec boluses manufactured for animal care. According to the directions of the manufacturer, the boluses were inserted into the reticulorumen of the cows researched with the help of a specific tool. The boluses were inserted into the abomasa by way of surgery, laparotomy and abomasotomy through the right flank. The readings of 7 cows were taken on a total of 10 days, twice a day (at 9 a.m. and at 9 p.m.). In total, 140 measurements were taken. The acidity of the reticulorumen is associated with the acidity of the abomasum. The acidity of the rumen increases, if the acidity of the reticulorumen increases also. A negative correlation was observed between the pH of the contents of the abomasum and this temperature. The increase in the acidity (decrease of pH) of the contents of the reticulorumen increases its temperature and also increases the temperature of the contents of the abomasum. There is a positive statistically significant dependence between the reticulorumen content temperature and the rectal temperature. Through measurement of the ruminoreticular temperature, it is possible to predict the health status of a cow's stomach in regard to acidosis.

Flavonoid supplementation is likely to be beneficial in improving rumen fermentation and in reducing the incidence of rumen acidosis and bloat. Flavonoids are also said to increase the metabolic performance during the peripartum period. Ruminants are constantly exposed to flavonoids present in feed. However, it is not clear if these phytochemicals can affect the activity of the gut smooth muscle. Therefore, the aim of the study was to verify the effect of three flavonoids on bovine isolated abomasum smooth muscle. The study was carried out on bovine isolated circular and longitudinal abomasal smooth muscle specimens. All experiments were conducted under isometric conditions. The effect of apigenin, luteolin and quercetin (0.001 to 100 µM) was evaluated on acetylcholine-precontracted preparations. The effect of multiple, but not cumulative, treatment and single treatment with each flavonoid on abomasum strips was compared. Apigenin (0.1 to 100 µM) dose-dependently showed myorelaxation effects. Luteolin and quercetin applied in low doses increased the force of the ACh-evoked reaction. However, if used in high doses in experiments testing a wide range of concentrations, their contractile effect either declined (luteolin) or was replaced by an antispasmodic effect (quercetin). Surprisingly, the reaction induced by flavonoids after repeated exposure to the same phytochemical was not reproducible in experiments testing only single exposure of abomasum strips to the same flavonoid used in a high concentration. Taking into account the physicochemical properties of flavonoids, this data suggests the ability of flavonoids to interfere with cell membranes and, subsequently, to modify their responsiveness. Assuming ruminant supplementation with luteolin or quercetin or their presence in daily pasture, a reduction of the likelihood of abomasum dysmotility should be expected.

Aim: To determine whether the retention time of curd in the abomasum of calves was influenced by supplementing milk with a plant-derived carbohydrate and amino acid supplement, evaluated non-invasively using ultrasonography., Methods: Female dairy calves aged between 2-6 days of age were sourced from a commercial farm in March 2013. All calves were fed whole milk until weaning (4 L per day); 21 calves were supplemented with a probiotic until 18 days of age, and thereafter with a plant-derived complex carbohydrate and amino acid supplement until weaning, and 22 calves were just fed whole milk. Treatment groups were balanced for age, weight and breed. At 9-14, 24-29 and 52-57 days of age, the abomasum of each calf was examined using ultrasonography immediately before and after feeding, 1 and 2 hours after feeding, and then at 30 minute intervals until curd was no longer visible in the abomasum. Abomasal volume and curd size were recorded to assess retention time of curd in the abomasum., Results: At 9-14 days of age, mean retention time of curd in the abomasum was similar (4.6 hours) in both groups. At 24-29 days of age, when the supplemented calves had been receiving the supplement for approximately 10 days, mean curd retention time was longer by 1.4 (SE 0.28) hours in supplemented compared with unsupplemented calves (p<0.001). At 52-57 days of age, mean retention time was longer by 0.7 (SE 0.34) hours compared to unsupplemented calves (p=0.05)., Conclusion: Using ultrasonography, changes in abomasal content could be followed non-invasively over time and it was demonstrated that the plant-derived complex carbohydrate supplement increased the curd retention time in the abomasum. We speculate that the increased retention time enables an increased availability of nutrients following a more complete digestion of milk, thereby improving animal performance.

The objectives were to assess the use of nicotinic acid (NA) to chronically (i.e., 74 h) manipulate plasma nonesterified fatty acid (NEFA) concentrations in partially feed-restricted lactating cows, determine whether the reduction of plasma NEFA altered responses to i.v. glucose tolerance test (ivGTT) and whether NA would attenuate an acute lipolytic stimuli of a β-agonist challenge (ivBAC). Eight lactating dairy cows [244 ± 31 d in milk; 696 ± 63 kg of body weight (BW)] were blocked by breed and body condition score (3.2 ± 0.4) and randomly assigned to a sequence of 2 treatments in a crossover design. Treatments were 74-h continuous abomasal infusion of NA solution (3mg/h per kg of BW) as an antilipolytic agent to decrease plasma NEFA concentrations or the same volume of water (200 mL/h), concomitant with partial feed restriction. From 0 to 74 h of each experimental period, cows were feed-restricted to 33% of the ad libitum intake recorded during the prior 5 d. An ivGTT (0.25 g/kg of BW of glucose i.v.) and an ivBAC (4 nmol/kg of BW of isoproterenol hydrochloride, i.v.) were performed at 48 and 72 h, respectively. Intake was 24.1, 8.2, 8.0, and 8.0 kg of dry matter/d before restriction, on d 1, 2 and 3, respectively. Nicotinic acid decreased plasma NEFA and increased insulin and glucose concentrations during feed restriction. Nicotinic acid also led to greater glucose and insulin response areas under the curve during ivGTT [glucose: 6,562 vs. 5,056 (mg/dL) × 180 min; insulin: 6,042 vs. 2,502 (µIU/mL) × 180 min] and ivBAC [glucose: 535 vs. 240 (mg/dL) × 120 min; insulin: 1,283 vs. 222 (µIU/mL) × 120 min], and enhanced NEFA area under the curve during ivBAC [45,521 vs. 22,862 (µEq/L) × 120 min]. Milk, fat, and protein yields (29.1, 1.2, and 0.93 kg on d -2, respectively) decreased to 17.9, 0.81, and 0.56 kg for control, and 11.5, 0.54, and 0.39 kg for NA on d 3, respectively. Nicotinic acid may have decreased production by inhibiting the supply of NEFA for energy and milk fat synthesis. Milk urea nitrogen was increased by NA on d 2 (12.8 vs. 19.1mg/dL) and d 3 (11.6 vs. 17.8 mg/dL), probably due to a greater reliance on mobilized amino acids. Somatic cell count was increased by NA on d 3 (187 vs. 848 × 1,000 cells/mL). Patterns of glucose and insulin concentration observed during 74 h of NA infusion reflect a state of insulin resistance, which contrasts with shorter-term responses in nonlactating cows. Data suggest that long-term supraphysiological infusion of NA affected intermediary metabolism beyond antilipolysis and did not inhibit acute lipolytic stimuli of ivBAC., (Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

In case of diarrhea calves are treated with oral rehydration solutions (ORS), which are known to increase abomasal pH and inhibit milk clotting in vitro. Nevertheless, recent studies have shown that ORS with HCO3(-) ≤ 62 mmol/L do not interfere with abomasal milk clotting in healthy calves. However, in diarrheic calves, feeding ORS and milk simultaneously may disturb abomasal curd formation and exacerbate diarrhea due to faster abomasal passage of ingesta. Therefore, the aim of the present study was to ultrasonographically examine abomasal milk clotting and diameter after feeding milk and milk replacer (MR) with and without ORS to healthy and diarrheic calves. Abomasal curd formation and diameter in healthy and diarrheic calves were ultrasonographically imaged before and after feeding milk, MR and ORS prepared in milk or MR. Feeding mixtures of milk or MR with ORS did not cause any remarkable differences in the ultrasonographic images of abomasal content. Moreover, abomasal milk clotting was not disturbed due to diarrhea. Statistically significant differences of abomasal diameter after feeding between healthy and diarrheic calves indicated that abomasal emptying is delayed in diarrheic calves. Hence, further studies are needed to determine reasons for decelerated abomasal passage in calves suffering from diarrhea., (© 2015 Japanese Society of Animal Science.)

This study examined mean retention time (MRT) of particulate and liquid matter in different segments of the gastrointestinal tract (GIT) of growing Saanen goats of different sexes and subjected to different levels of feed restriction. In addition, feeding behavior and total tract digestibility were determined for all animals ahead of slaughter. In total, 54 Saanen goats (18 each of females, castrated males, and intact males) with initial BW 15.3 ± 0.4 kg were used in a 3 × 3 factorial arrangement comprising the 3 sexes and 3 levels of feed restriction (unrestricted/ad libitum, moderate, and severe restriction). Six blocks per sex group, each consisting of 3 goats, were randomly formed and the goats within each block were randomly allocated to 1 of 3 different feed restrictions. The daily amounts of feed offered to animals subjected to moderate and severe feed restriction (approximately 75% and 50% of ad libitum rate, respectively) were determined within block based on the DMI by ad libitum fed goats on the previous day. The MRT of particulate matter was determined either using Yb-labeled diet or indigestible NDF (iNDF) determined in situ as markers. Mean retention time of the liquid phase was determined by Cr-EDTA. Orthogonal polynomial contrasts were used to determine linear and quadratic effect of feed restriction, while the effect of sex was compared by Tukey test. The effects of sex and the interaction between sex and feed restriction were not significant on most of variables evaluated. Eating, ruminating, and total chewing time per g DM and NDF intake increased linearly as feed restriction increased (P ≤ 0.03). Diet digestibility increased quadratically for DM and OM, and linearly for NDF as feed intake decreased (P ≤ 0.03). The MRT of iNDF in the reticulorumen, omasum, abomasum, colon, and total GIT increased linearly with increased feed restriction (P ≤ 0.01). Mean retention time in the cecum varied quadratically, being greatest for animals with moderate feed restriction. The MRT of liquid was quadratically (P ≤ 0.04) affected by feed restriction in the reticulorumen, cecum, and total GIT, with the greatest MRT observed for animals subjected to moderate feed restriction. In conclusion, the level of feed restriction increased the MRT of particulate and liquid matter. The MRT was an important mechanism to increase nutrient supply when animals were subjected to feed restriction, as indicated by increased total tract digestibility.

The effects of various selective phosphodiesterase (PDE) inhibitors on carbachol (CCh)-induced contraction in the bovine abomasum were investigated. Various selective PDE inhibitors, vinpocetine (type 1), erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA, type 2), milrinone (type 3), Ro20-1724 (type 4), vardenafil (type 5), BRL-50481 (type 7) and BAY73-6691 (type 9), inhibited CCh-induced contractions in a concentration-dependent manner. Among the PDE inhibitors, Ro20-1724 and vardenafil induced more relaxation than the other inhibitors based on the data for the IC50 or maximum relaxation. In smooth muscle of the bovine abomasum, we showed the expression of PDE4B, 4C, 4D and 5 by RT-PCR analysis. In the presence of CCh, Ro20-1724 increased the cAMP content, but not the cGMP content. By contrast, vardenafil increased the cGMP content, but not the cAMP content. These results suggest that Ro20-1724-induced relaxation was correlated with cAMP and that vardenafil-induced relaxation was correlated with cGMP in the bovine abomasum. In conclusion, PDE4 and PDE5 are the enzymes involved in regulation of the relaxation associated with cAMP and cGMP, respectively, in the bovine abomasum.

Impaired abomasal motility is common in cattle with abomasal disorders. The macrolide erythromycin has been demonstrated to be an effective prokinetic agent in healthy calves and in adult cattle with abomasal volvulus or left displaced abomasum. We hypothesized that 2 structurally related macrolides, spiramycin and tulathromycin, would also be effective prokinetic agents in cattle. Six milk-fed, male, Holstein-Friesian calves were administered each of the following 4 treatments: spiramycin, 75 000 IU/kg BW, IM, this dose approximates 25 mg/kg BW, IM; tulathromycin, 2.5 mg/kg BW, SC; 2 mL of 0.9% NaCl (negative control); and erythromycin, 8.8 mg/kg BW, IM (positive control). Calves were fed 2 L of cow's milk containing acetaminophen (50 mg/kg body weight) 30 min after each treatment was administered and jugular venous blood samples were obtained periodically after the start of sucking. Abomasal emptying rate was assessed by the time to maximal plasma acetaminophen concentration. Spiramycin, tulathromycin, and the positive control erythromycin increased abomasal emptying rate compared to the negative control. We conclude that the labeled antimicrobial dose of spiramycin and tulathromycin increases the abomasal emptying rate in healthy milk-fed calves. Additional studies investigating whether spiramycin and tulathromycin exert a prokinetic effect in adult cattle with abomasal hypomotility appear indicated.

In this pilot study, the effects of phosphorus (P) supply on inorganic phosphorus (Pi ) net absorption in dairy cows were investigated. Three non-lactating, non-pregnant, rumen-fistulated Swedish Red breed dairy cows were studied in a 3 × 3 Latin square design. Monosodium dihydrogen orthophosphate dihydrate (NaH2 PO4 *2H2 O) was continuously infused into the abomasum for 4 days. The solutions provided 0, 14.4 or 28.8 g Pi /day. Rumen fluid volume and outflow rate were estimated at day four of each experimental period using cobalt-lithium EDTA as an external marker. Acid insoluble ash in feeds and faecal samples was used to quantify P faecal excretion. Concentrations of Pi in collected samples of rumen fluid, blood, faeces and urine were determined. Pi flow into the small intestine increased (p < 0.05) with Pi infusion. Pi net absorption tended to increase (p = 0.08) but proportion of absorbed Pi tended to decrease (p = 0.08). Urinary Pi excretion was negligible and did not affect P homoeostasis (p = 0.50). There was no change in plasma Pi concentration (p = 0.45) in response to Pi infusion. The increase in total faecal P excretion (p < 0.05) with increasing level of infused Pi was solely because of increased soluble faecal Pi (p < 0.05). It is suggested that at P overfeeding, intestinal Pi net absorption is saturable in dairy cows., (© 2012 Blackwell Verlag GmbH.)

Cows with left displaced abomasum (LDA), a costly disease occurring primarily in multiparous dairy cows during early lactation, have been reported to have 40% lower circulating concentrations of vitamin E. It is unknown, however, whether the lower circulating α-tocopherol concentrations precede LDA or remain after LDA. Using a nested case-control design, blood samples taken at d -21, -14, -7, -3, -1, 0, 1, 3, 7, 14, 21, 28, 35, 42, and 49 postpartum from 7 multiparous Holstein cows diagnosed with LDA between d 6 and 32 postpartum and 10 healthy Holstein cows from the same herd were analyzed for serum concentrations of α-tocopherol and indicators of energy and nutrient status and inflammation. In addition to indicators of negative energy balance and inflammation, lower serum α-tocopherol concentrations preceded LDA and persisted after LDA correction. At the last blood sampling before LDA diagnosis, cows had serum α-tocopherol concentrations 45% lower (5.0 ± 0.9 vs. 9.1 ± 0.9 µM) and α-tocopherol to cholesterol molar ratios 39% lower (1.90 ± 0.19 vs. 3.09 ± 0.26) than those of healthy cows. Serum α-tocopherol concentrations remained lower (<10 vs. ~15 µM) up to d 49 postpartum in cows that had LDA. These findings indicate that lower serum α-tocopherol concentrations are a potential early indicator for the development of LDA in multiparous cows., (Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The effects of abomasal infusion of oligofructose in lactating dairy cows on the relationship between hindgut fermentation and N metabolism, and its effects on NH(3) absorption and transfer of blood urea-N across the portal-drained viscera versus ruminal epithelia were investigated. Nine lactating Holstein cows fitted with ruminal cannulas and permanent indwelling catheters in major splanchnic blood vessels were used in an unbalanced crossover design with 14-d periods. Treatments were continuous abomasal infusion of water or 1,500 g/d of oligofructose. The same basal diet was fed with both treatments. Eight sample sets of arterial, portal, hepatic, and ruminal vein blood, ruminal fluid, and urine were obtained at 0.5h before the morning feeding and at 0.5, 1.5, 2.5, 3.5, 4.5, 5.5, and 6.5 h after feeding. It was hypothesized that an increased supply of fermentable substrate to the hindgut would increase the uptake of urea-N from blood to the hindgut at the expense of urea-N uptake to the forestomach. The study showed that abomasal oligofructose infusion decreased the total amount of urea-N transferred from the blood to the gut, NH(3) absorption, and arterial blood urea-N concentration. Subsequently, hepatic NH(3) uptake and urea-N production also decreased with oligofructose infusion. Additionally, urea-N concentration in milk and urinary N excretion decreased with oligofructose treatment. The oligofructose infusion did not affect ruminal NH(3) concentrations or any other ruminal variables, nor did it affect ruminal venous - arterial concentration differences for urea-N and NH(3). The oligofructose treatment did not affect milk yield, but did decrease apparent digestibility of OM, N, and starch. Nitrogen excreted in the feces was greater with the oligofructose infusion. In conclusion, the present data suggest that increased hindgut fermentation did not upregulate urea-N transfer to the hindgut at the expense of urea-N uptake by the rumen, and the observed reduction in arterial blood urea-N concentration appeared not to be due to increased urea-N transport, but rather could be explained by reduced NH(3) input to hepatic urea-N synthesis caused by increased sequestration of NH(3) in the hindgut and excretion in feces. Increasing the hindgut fermentation in lactating dairy cows by abomasal infusion of 1,500 g/d of oligofructose shifted some N excretion from the urine to feces and possibly reduced manure NH(3) volatilization without impairing rumen fermentation., (Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Inadequate absorption of colostral IgG in calves increases the risk of morbidity and death and is an important source of economic loss to the dairy industry. We hypothesized that an increased rate of abomasal emptying in colostrum-fed calves would be associated with an increased apparent efficiency of absorption (AEA) of colostral IgG. This is because an increase in abomasal emptying rate causes IgG to reach the site of absorption in the small intestine earlier and at a higher luminal concentration. The main objective was, therefore, to determine the association between the AEA of colostral IgG and abomasal emptying rate in neonatal calves. Twenty-four neonatal Holstein-Friesian calves were randomly assigned to one of the following treatments: control, 2 mL of 0.9% NaCl intramuscularly; erythromycin, 8.8 mg/kg of body weight intramuscularly; ivermectin, 200 μg/kg intravenously; and gentamicin, 6.6 mg/kg intramuscularly. These treatments were selected because we have previously demonstrated that erythromycin and ivermectin increase, and gentamicin decreases, the rate of abomasal emptying in milk-fed calves. Calves were fed 3 L of pooled cow colostrum containing acetaminophen (50mg/kg of body weight) by oroesophageal intubation at 1h of age and 30 min after each treatment was administered. Jugular venous blood samples were obtained periodically after the start of feeding. Abomasal emptying rate was assessed by the time to maximal plasma acetaminophen concentration. Erythromycin increased and gentamicin decreased the abomasal emptying rate and AEA of colostral IgG compared with control, respectively, whereas ivermectin had no effect. Using data from all 24 calves, the AEA of colostral IgG was linearly and negatively associated with abomasal emptying rate (R(2)=0.22). We conclude that the abomasal emptying rate is an important determinant of the AEA of colostral IgG. Identifying a non-antimicrobial method for increasing abomasal emptying rate will provide a practical and effective method for facilitating transfer of passive immunity in colostrum-fed dairy calves., (Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Objective: To determine the effects of 3 commercially available, orally administered electrolyte solutions (OAEs) on abomasal luminal pH and emptying rate in dairy calves, compared with the effect of orally administered milk replacer., Design: Randomized crossover study., Animals: 6 male dairy calves (age, 12 to 31 days)., Procedures: Calves were surgically instrumented with an abomasal cannula and were administered 4 treatments in randomized order: all-milk protein milk replacer, high-glucose high-bicarbonate OAE, high-glucose high-bicarbonate OAE containing glycine, and low-glucose OAE containing acetate and propionate. Abomasal luminal pH was measured with a miniature glass pH electrode prior to treatment administration and every second afterward for 24 hours., Results: Feeding of orally administered milk replacer resulted in a rapid increase in mean abomasal luminal pH from 1.3 to 5.8, followed by a gradual decrease to preprandial values by 8 hours afterward (mean 24-hour pH, 3.2). High-glucose high-bicarbonate OAEs caused a large and sustained increase from 1.3 to 7.5 (mean 24-hour pH, 4.1 for the solution without glycine and 3.5 for the solution with glycine). In contrast, feeding of the acetate-containing OAE was followed by only a mild and transient increase (mean 24-hour pH, 2.1); luminal pH returned to preprandial values by 3 hours after ingestion., Conclusions and Clinical Relevance: Ingestion of a bicarbonate-containing OAE resulted in sustained abomasal alkalinization in dairy calves. Because persistently high abomasal luminal pH may facilitate growth of enteropathogenic bacteria, administration of OAEs containing a high bicarbonate concentration (> 70mM) is not recommended for calves with diarrhea.

The left displacement of the abomasum (LDA) is a common disease in periparturient dairy cows. Plasma β-hydroxybutyrate (BHBA) levels above the reference range are regarded as risk factors for the occurrence of LDA. Additionally, hypokalemia and hypocalcemia have been observed in LDA cows. The aim of the present study was to characterize the membrane potential and the slow waves in abomasal smooth muscle cells by a microelectrode technique and to determine possible effects of BHBA and of various calcium and potassium concentrations on the membrane potential. Subsequently, the results obtained by the microelectrode technique were combined with in vitro motility experiments of abomasal smooth muscles. Strips of the abomasal circular smooth muscles were prepared and incubated in different buffer solutions. For the microelectrode technique, healthy bulls and cows that underwent surgery for LDA were sampled. These measurements showed a frequency of the slow waves between 3.5 and 10.9 per minute (for amplitudes ≥ 3mV) and between 0.6 and 4.5 per minute (for amplitudes ≥ 5mV). The frequency of contractions (1.8 to 3.1 per minute) were in the same order as the frequency of the slow waves with amplitudes ≥ 5 mV. Blocking potassium conductance with barium chloride induced a depolarization of the basal membrane potential (from -43±2.9 to -37±4.1mV; mean ± standard error of the mean) without affecting the frequency or the height of the slow waves. The reduction in the potassium concentration from 5.4 to 2 mmol/L resulted in a nominal decrease in the activity of contractions (from 22.2 to 18.6 mN/min). The subsequent addition of 1 mmol of KCl/L induced a nominal increase in contraction activity (from 18.6 to 25.7 mN/min). An effect of BHBA (5 mmol/L) could not be demonstrated, neither on the electric nor on the motility parameters. A simulated hypocalcemia (1.2 mmol/L total, 0.9 mmol/L ionized Ca) did not change slow waves and motility. In conclusion, changes in membrane potential ≥ 5 mV correlated with contractions of abomasal muscles. Hypokalemic conditions may reduce abomasal contraction activity via an effect on the membrane potential. An exclusive increase in BHBA or a slight hypocalcemia (0.9 mmol/L ionized Ca) had no effects on the motility of healthy abomasal smooth muscle cells. A prolonged or severe exposition of muscles to a combination of low Ca and high BHBA concentrations might nevertheless be able to affect abomasal motility., (Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The objective of this study was to determine the fatty acid (FA) profile and assess desaturase indices of nonesterified fatty acids (NEFA) in the blood, as well as in the abdominal (ABD) and subcutaneous (SUBC) fat stores, in dairy cows with left displacement of the abomasum (LDA). Blood, ABD, and SUBC samples were taken from 50 Holstein cows offered for surgery to correct LDA. The FA profile of the 3 compartments was determined by gas chromatography after lipid extraction, methylation, and, in the case of blood plasma, separation of lipid classes. The most abundant FA in all 3 compartments were 16:0, 18:0, and 18:1 cis-9, with a total proportion of 82.5, 68.0, and 74.1g/100 g of FA in ABD, NEFA, and SUBC, respectively. A principal component analysis was performed on the entire FA profile as well as on the Δ(9)-desaturase indices (14:1 cis-9/14:0, 16:1 cis-9/16:0, 18:1 cis-9/18:0). The principal component analysis extracted 2 principal components (PC), representing 51.6% (PC1) and 21.1% (PC2) of the total variance in FA composition of the 3 compartments. The loading plot for the regression factors revealed a strong positive correlation between PC1 with the Δ(9)-desaturase indices and the proportions of 14:1 cis-9 and 16:1 cis-9, and revealed a negative correlation with the proportion of 18:0 and saturated FA. The correlation with PC2 was positive for the proportion of unsaturated FA, 18:2n-6, and 18:3n-3, and negative for the proportion of 14:0, 16:0, and saturated FA. The SUBC could be distinguished from the NEFA and ABD by a positive score for PC1, whereas differentiation among the latter 2 compartments could be made by a positive (NEFA) or negative (ABD) score for PC2. The Δ(9)-desaturase indices for C14 and C16 differed between all compartments but were numerically closer for NEFA and ABD versus NEFA and SUBC. The desaturase indices of the main FA (18:1 cis-9 and 18:0) did not differ between NEFA and ABD. These results support the existence of a different FA composition in ABD compared with SUBC. The greater similarity between the FA profiles of ABD and NEFA compared with SUBC and NEFA and the closer desaturase indices of ABD and NEFA support the hypothesis of a preferential mobilization of ABD fat in dairy cows with LDA., (Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The experiment was designed to study the importance of early rumen development and of the composition of solid feed intake on growth performance and abomasal health in milk-fed veal calves. One hundred and six Holstein-Friesian male calves were included in the experiment, and studied during 2 successive 12-wk periods (period 1 and period 2). In a 2 × 2 factorial arrangement, effects of partially replacing milk replacer by solid feed during period 1 and partially replacing dry matter (DM) intake from maize silage and barley straw by concentrate during period 2 were tested. Solid feed during period 1 consisted of maize silage, barley straw, and concentrate (25:25:50 on a DM basis). Solid feed during period 2 consisted of maize silage and barley straw (50:50 ratio on DM basis) for the nonconcentrate groups, and maize silage, barley straw and concentrates (25:25:50 on a DM basis) for the concentrate groups. At the end of period 1 (n=16) and at the end of period 2 (n=90), parameters of animal performance, rumen development, rumen fermentation, ruminal drinking, and abomasal damage were examined. Partially replacing milk replacer by solid feed during period 1 resulted in early rumen development (ERD) at the end of period 1, characterized by increased rumen weight, and an increased epithelial and absorptive surface area. Both ERD and partially replacing roughage by concentrates in period 2 increased the rumen development score at the end of period 2. Although ERD calves consumed more solid feed and less milk replacer during period 1 and 2 than non-ERD calves, carcass weight gains at 25 wk were identical, and utilization of the solid feed provided appeared similar to that of milk replacer. Partially replacing roughage by concentrates in period 2 increased dressing percentage and warm carcass weight. Plaque formation at the rumen mucosa was unaffected by ERD or partially replacing roughage by concentrates and generally low in all calves. The prevalence of large scars in the abomasum in ERD calves was decreased compared with non-ERD calves. This may indicate that ERD provided protection against abomasal lesions. In conclusion, early compared with late rumen development improves feed utilization and may be beneficial for abomasal health., (Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Objective: To assess the suitability of the modified acetaminophen absorption test for evaluation of abomasal emptying rate in ruminating cattle., Animals: 7 Holstein-Friesian heifers., Procedures: In a crossover study design, heifers consecutively underwent an IV infusion of 1 L of saline (0.9% NaCl) solution (control treatment), 1 L of saline solution containing metoclopramide (0.1 mg/kg), and 1 L of saline solution containing atropine (0.1 mg/kg), with an interval of 15 days between treatments. Immediately after each treatment, acetaminophen diluted in ethanol (50 mg/kg) was infused transcutaneously into the abomasum. Blood samples were obtained repeatedly for measurement of plasma acetaminophen concentration, and pharmacokinetic data were obtained., Results: Maximum plasma acetaminophen concentration was significantly lower after atropine treatment than after control or metoclopramide treatment, whereas no difference was identified between control and metoclopramide treatments. The interval to maximum plasma acetaminophen concentration was significantly longer in atropine-treated versus metoclopramide-treated heifers. The interval to maximum acetaminophen concentration obtained from a pharmacokinetic model was significantly longer for atropine than for control and metoclopramide treatment. Similarly, areas under the plasma acetaminophen concentration-time curves for the first 60, 90, 120, and 240 minutes after administration were significantly lower for atropine versus metoclopramide or control treatment, whereas differences between metoclopramide and control treatments were not identified., Conclusions and Clinical Relevance: The modified acetaminophen absorption test was a practical, minimally invasive, and reliable method to assess abomasal emptying in cattle. Metoclopramide administered at a dose of 0.1 mg/kg did not increase the abomasal emptying rate.

To better understand the mechanism of excessive gas accumulation in the abomasum in bovine abomasal displacement, we performed gastric fluoroscopy in vagotomized cattle. Fifteen 6-month-old Holstein steers were divided into three groups: a non-vagotomized control group (Group C; n=5), a ventral thoraco-vagotomized group (Group V; n=5), and a dorsal and ventral thoraco-vagotomized group (Group DV; n=5). These groups were examined by fluoroscopy before and during a 5-week observation period after surgery. In Group C, no change was observed throughout the observation period. In Group DV, immediately after surgery, reticuloruminal motility was completely absent and ruminal distention was seen. Two weeks after surgery, abnormal reticulum motility and increased gas accumulation in the abomasal body were noted. Abomasal dilatation was also observed. In Group V, 1 week after surgery, gas inflow into the abomasum and relatively normal reticulum motility were observed along with a rapid increase in abomasal gas. Abomasal dilatation was also observed. In addition, left-displaced abomasum occurred in one of the steers in this group. From these results, we concluded that one of the mechanisms of excessive gas accumulation in the abomasum is reticulum-mediated gas inflow from the rumen combined with vagotomy-induced hypomotility.

This experiment was conducted to investigate the difference between ruminal (solid feed, SF) and abomasal (liquid feed, LF) feeding on the plasma leptin concentration in sheep. The experiment consisted of 2 weeks to adapt the animals to SF, 4 weeks of feeding on SF, 2 weeks adaptation to LF, 8 weeks of feeding on LF, 2 weeks of adaptation to SF, and 4 weeks of feeding on SF. The LF directory flowed into the abomasums of sheep by bottle feeding. Plasma leptin concentration before morning feeding was almost constant in the SF periods, whereas it showed between-day variations when measured during the LF periods. Mean plasma leptin levels were higher for LF (7.77 ± 0.76 ng/mL; mean ± SE) than for SF periods (3.95 ± 0.16 ng/mL; mean ± SE). Although plasma leptin concentration did not show any change after feeding in the SF and LF periods, plasma insulin and glucose levels increased within 15 min after liquid abomasal feeding, but not after solid ruminal feeding. The high plasma leptin concentration during the LF periods in weaned sheep could be due to change of digestible energy intake and changes in plasma insulin and glucose levels accompanying the changes in digestive processes and nutrient supply., (© 2010 The Authors. Journal compilation © 2010 Japanese Society of Animal Science.)

Abomasal displacement is a frequent and important disease of high yielding dairy cows. Although several factors are related to its occurrence, the pathogenesis of the condition is still inadequately understood, particularly in regard to K(+) and insulin homeostasis. For this reason the aim was to investigate the effects of K(+) and insulin concentrations on in vitro motility of abomasal smooth muscle. The second aim was to determine whether the in vivo change in K(+) and insulin levels might be sufficient to induce reduced abomasal motility. Muscle strips were isolated from the abomasum of slaughtered cows and incubated in buffer solution under isometric conditions. Results show that a decrease in extracellular K(+) (between 5 and 1 mmol/L) or an increase in extracellular insulin concentrations (to 21 mU/L or higher) were able to affect the contraction activity of abomasal muscles. Contraction activity given as median (25th, 75th percentiles) changed from 28.1 mN/min (2.5, 49.9) at 5 mmol/L of K(+) to 9.4 mN/min (0.6, 35.7) at 1 mmol/L of K(+), and from 34.5 mN/min (10.8, 112.4) at 0 mU/L of insulin to 12.0 mN/min (7.6, 49.8) at 120 mU/L of insulin. Because the effect of insulin could be abolished by barium, glybenclamide, or ouabain, the underlying mechanisms of the insulin action could be an increased K(+) conductance or an increased Na/K-ATPase activity or both. Low K(+) or high insulin concentrations both reduced the activity of the circular muscle of the abomasal corpus (i.e., of the part that is responsible for the propulsion of abomasal chymus) and might play an important role in the pathogenesis of abomasal displacement., (Copyright (c) 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The objective of the study was to measure net AA flux rates across the portal-drained viscera (PDV) and liver in the presence and absence of abomasal glucose infusion. Decreasing the fraction of AA metabolized by the mucosal cells may increase the fraction of AA being released into the blood. A potential mechanism to reduce AA catabolism by mucosal cells is to provide an alternative source of energy. We hypothesized that increasing glucose flow to the small intestine would increase net appearance of AA across the PDV. Eighteen mature ewes with sampling catheters were placed on study. The experimental design was a split-plot with a complete randomized design on the whole-plot and a Latin-square subplot with 5 periods and incremental levels of protein infusion. One-half of the ewes received abomasal glucose infusions (3.84 g/h), and all ewes received each of 5 protein abomasal infusion levels over 5 periods (0, 2.6, 5.2, 7.8, and 10.5 g/h). Net PDV release of isoleucine, leucine, methionine, phenylalanine, aspartate, glutamate, glutamine, proline, serine, and tyrosine increased linearly with increased protein infusion, and net PDV release of histidine, lysine, threonine, valine, alanine, and glycine did not differ with protein infusion. Net hepatic glucose release decreased with glucose infusion. With the exception of histidine, phenylalanine, and valine, net hepatic AA uptake increased linearly with increased delivery of AA to the liver. Glucose infusion increased the hepatic lysine and valine uptake and decreased phenylalanine uptake. Based on the observations in the current study, we reject our hypothesis that glucose can spare AA metabolism by PDV tissue. Our findings suggest that hepatic gluconeogenesis can be increased in the presence of increased AA delivery to the liver and that hepatic gluconeogenesis can be decreased with increased absorption of dietary glucose. Our findings support the concept that for most AA, hepatic transport of AA can be described by mass action kinetics; however, the rates of hepatic uptake of specific AA are upregulated directly or indirectly by elevated glucose.

Eight Holstein bull calves were divided into two groups; a non-treated control group and a famotidine treated group. Fresh milk was fed twice a day. The experiment was conducted between 7 and 14 days of age. During the experimental period the control group was injected with physiological saline, and the famotidine group was injected with famotidine, a histamine-H2-receptor blocker, into the jugular vein 30 minutes prior to each feeding. The control group showed maximum curd formation 2 h after feeding at both 7 and 14 days of age. Curd scores of 7-day-old and 14-day-old calves were significantly lower in the famotidine than in the control group at 2 and 4 h after feeding. Most fecal samples from the famotidine group exhibited an acidic smell. The famotidine group showed significantly lower values for both average weight gain and the rate of weight gain from 7 to 14 days of age. The inhibition of gastric acid secretion decreased curd formation in the abomasum as well as daily weight gain compared to non-treated control calves. This suggested that curd formation in the abomasum is important for the weight gain of newborn calves.

OBJECTIVE-To evaluate the effect of parenteral administration of ivermectin and erythromycin on abomasal emptying rate in suckling calves. ANIMALS-6 male Holstein-Friesian calves < 15 days old. PROCEDURES-In a crossover study, calves were administered each of 3 treatments (control treatment, 2 mL of saline [0.9% NaCl] solution, IM; erythromycin, 8.8 mg/kg, IM; and ivermectin, 200 microg/kg, IV). Thirty minutes later, calves were bottle-fed 2 L of fresh cow's milk containing acetaminophen (50 mg/kg). Blood samples were collected from a jugular vein at various periods after suckling of milk. Abomasal emptying rate was assessed by use of the time to pharmacokinetically determined maximal plasma acetaminophen concentration. RESULTS-Administration of erythromycin and ivermectin caused a significant increase in abomasal emptying rate, compared with results for the control treatment, as determined on the basis of time to maximal plasma acetaminophen concentration. CONCLUSIONS AND CLINICAL RELEVANCE-Parenteral administration of erythromycin and ivermectin increased the abomasal emptying rate. The macrolide erythromycin can be an effective prokinetic agent in calves and other animals. Ivermectin is classified as a macrolide but has a number of structural differences from erythromycin. The clinical importance of a slight increase in abomasal emptying rate after IV administration of ivermectin remains to be determined because ivermectin is only labeled for SC, oral, and topical administration.

Objective: To determine and compare the effects of 4 oral replacement therapy (ORT) solutions on acid-base balance, abomasal emptying rate, and plasma volume expansion in calves with naturally acquired diarrhea and moderate dehydration., Design: Prospective study., Animals: 20 calves., Procedures: 20 calves up to 45 days of age were randomly allocated (n = 5/group) to receive 2 L of 1 of 4 treatments via oroesophageal intubation: sodium bicarbonate (150 mmol/L or 300 mmol/L) or sodium acetate (150 mmol/L or 300 mmol/L). The 4 test solutions contained acetaminophen (50 mg/kg [22.7 mg/lb]) and 50 g of glucose monohydrate. Jugular venous blood samples were obtained periodically before and after administration of the ORT solution. Abomasal emptying rate was determined by use of the time to maximal plasma acetaminophen concentration., Results: Plasma bicarbonate concentration increased more rapidly in calves administered bicarbonate-containing ORT solutions, whereas the rate of systemic alkalinization, as assessed via blood pH, did not differ consistently among treatments. The 300 mmol/L ORT solutions were emptied at a significantly slower rate from the abomasum than 150 mmol/L ORT solutions, with no difference in emptying rate between acetate and bicarbonate-containing ORT solutions of similar molality. The 300 mmol/L sodium acetate ORT solution significantly increased plasma volume., Conclusions and Clinical Relevance: Clinically important differences in the resuscitative response to 300 mmol/L or 150 mmol/L ORT solutions of sodium acetate or sodium bicarbonate were not identified.

Inadequate milk curd formation in the abomasum of newborn calves causes malnutrition and diarrhea. In order to define the factors of inadequate curd formation, we compared the curd forming ability among 9 kinds of milk replacers, bulk milk (raw milk), and skim milk both in vitro and in vivo. When rennet was added, the raw milk and one milk replacer formed firm curds. The rest of the milk replacers and skim milk did not form any curd. When a solution of HCl was added, raw milk, three milk replacers and skim milk formed the curd at pH 4.5, but the other milk replacers did not. When HCl was added following the rennet, raw milk, one milk replacer and skim milk formed the curd. In vivo, raw milk, two milk replacers and skim milk showed good curd formation whereas the other milk replacers showed poor curd formation inside the abomasums of the calves. This study showed that most of the milk replacers sold in Japan could not form the curd with rennet.

We examined the physiological role of nitrergic nerves in the regulation of omasal and abomasal motility in conscious healthy sheep and omasal muscle specimens. Nitric oxide (NO)-donor, S-nitroso-acethyl-dl-penicillamine (SNAP, 3-30 nmol/kg per min, i.v.) significantly inhibited omasal electromyographic (EMG) activity, whereas it did not alter EMG activity in the abomasal antrum. However, NO synthase inhibitor, Nomega-nitro-l-arginine-methyl ester (L-NAME, 0.3-3.0 micromol/kg per min, i.v.) did not alter EMG activity of the omasum and abomasum. In the in vitro experiments, SNAP application (6-200 micromol/l) significantly inhibited bethanechol (10 micromol/l)-induced contraction of longitudinal and circular muscles of the omasum. L-NAME application (0.03-3.0 mmol/l) enhanced electric field stimulation-induced contractions of the circular muscles. The results suggest that the omasal muscles are responsive to exogenous NO and that nitrergic nerves innervate the circular muscle layer of the omasum, however, nitrergic nerves are not or scarcely involved the physiological regulation of omasal and possibly abomasal motility in healthy sheep.

The nutritional cost of, and the sequential cellular changes associated with the developing immune response to the abomasal parasite Teladorsagia circumcincta were investigated using corticosteroid-induced immune-suppression. Six-month-old lambs with minimal nematode experience were either infected with 4000 L3 T. circumcincta per day (group IF), similarly infected and concurrently immune-suppressed with methylprednisolone acetate (group ISIF), immune-suppressed only (group IS) or remained as controls (group C). Food intake, faecal egg count (FEC) and antibody titres in plasma were recorded weekly, worm burden at necropsy on day 63 p.i. and body composition by X-ray computed tomography on days -2 and 62 p.i. Furthermore, sequential immunological changes at the site of parasite infestation in the abomasal mucosa were measured from serial biopsy tissue samples taken from additional animals that were fitted with an abomasal cannula and either infected with the same regime as IF animals above (group CnIF) or concurrently infected and immune-suppressed as above (group CnISIF). Corticosteroid treatment resulted in greater FECs (P<0.01) and worm burdens (P<0.01) in both ISIF and CnISIF compared with IF and CnIF sheep, respectively. Infection reduced feed intake by 17% between 14 and 28 days p.i. (P<0.05) and efficiency of energy utilisation by 20% (P=0.07) in IF animals but not in ISIF animals. Mast cells, globule leukocytes and IgA in tissue biopsy samples were elevated in CnIF from 42 days p.i., all of which were abrogated by corticosteroid treatment. The ability to regulate the worm population appeared to be associated with a rise in tissue IgA concentration and numbers of globule leucocytes (GL). The results support the hypothesis that a majority of the production losses that occur during infection of lambs with T. circumcincta in lambs are a consequence of the host immune response. These findings may have implications for regimes that promote the development of a strong host immune reaction to gastrointestinal parasites in lambs.

Abomasal displacement has been associated with gastric hypomotility. The supply of prokinetic drugs available to address this problem is insufficient. The goal of the study was to investigate the effect of the muscarinic agonist bethanechol (BeCh) on contractility parameters of smooth muscle preparations from several regions of the bovine abomasum (fundus, corpus, and antrum). Cumulative concentration-response curves were constructed using BeCh in vitro with and without pre-incubation with antagonists targeted at M(2) and M(3) muscarinic acetylcholine receptor (mAChR) subtypes. In all preparations investigated, BeCh induced a significant and concentration-dependent increase in all contractility parameters investigated. The maximal attainable effect (V(max)) was more pronounced in circular specimens, and V(max) of antral specimens in circular orientation were significantly lower when compared to the other preparations. Both antagonists caused a rightward shift of the concentration-response curve, suggesting that the effect of BeCh is mediated at least partly by M(2) and M(3) AChRs.

Background: Commonly used dosage protocols for antimicrobial agents may alter the rate of gastric emptying., Hypothesis: Parenteral administration of erythromycin increases and gentamicin decreases the rate of abomasal emptying., Animals: Five male Holstein-Friesian calves (8-15 days of age)., Methods: Calves received each of the following 4 IM treatments in random order: control, 2 mL of 0.9% NaCl; erythromycin, 8.8 mg/kg; low-dose gentamicin, 4.4 mg/kg; high-dose gentamicin, 6.6 mg/kg. Abomasal emptying rate was assessed by acetaminophen and glucose absorption. Calves were fed 2 L of cow's milk containing acetaminophen (50 mg/kg body weight) 30 minutes after each treatment was administered, and jugular venous blood samples were obtained periodically after suckling. The maximum observed plasma acetaminophen concentration (actual C(max)) and time of actual C(max) (actual T(max)) were determined, and pharmacokinetic modeling was used to calculate model C(max) and model T(max)., Results: Erythromycin increased abomasal emptying rate, as indicated by a shorter time to actual T(max) and model T(max) (P < .05). Abomasal emptying rate after injection of low-dose gentamicin was similar to that of control. Administration of high-dose gentamicin resulted in a longer time to actual T(max) (P= .021) but did not change model T(max) (P= .62)., Conclusions and Clinical Relevance: IM injection of erythromycin increased abomasal emptying rate in dairy calves, whereas low-dose and high-dose gentamicin did not alter the rate of abomasal emptying as measured by acetaminophen kinetics and glucose absorption. The clinical relevance of these findings remains to be determined.

Objective: To determine the effect of parenteral administration of erythromycin, tilmicosin, and tylosin on abomasal emptying rate in suckling calves., Animals: 8 male Holstein-Friesian calves < 35 days old., Procedures: Calves received each of 4 treatments in random order (2 mL of saline [0.9% NaCl] solution, IM [control treatment]; erythromycin, 8.8 mg/kg, IM; tilmicosin, 10 mg/kg, SC; and tylosin, 17.6 mg/kg, IM). Calves were fed 2 L of milk replacer containing acetaminophen (50 mg/kg) 30 minutes later. Jugular venous blood samples and transabdominal ultrasonographic abomasal dimensions were obtained periodically after suckling. Abomasal emptying rate was assessed on the basis of the time to maximal plasma acetaminophen concentration and ultrasonographic determination of the halftime of abomasal emptying. One-tailed Dunnett post tests were conducted whenever the F value for group was significant., Results: Emptying rate was faster for erythromycin, tilimicosin, and tylosin than for the control treatment, as determined on the basis of time to maximal plasma acetaminophen concentration. Ultrasonography indicated that the half-time of abomasal emptying was significantly shorter for erythromycin than for the control treatment. Tylosin and tilmicosin accelerated the abomasal emptying rate, but not significantly, relative to the emptying rate for the control treatment., Conclusions and Clinical Relevance: Administration of erythromycin, tilmicosin, and tylosin at the label dosage increased abomasal emptying rate in calves. The clinical importance of an increase in abomasal emptying rate in cattle remains to be determined.

The effects of intravenous infusion of proglumide on regular ruminal contractions were examined in conscious sheep using doses that inhibit pancreatic exocrine secretion. After a control period of 20 min, proglumide was infused intravenously for 40 min at a dose of 15, 30 or 60 micromol/kg per min and venous blood was collected. The intravenous infusion of proglumide significantly increased the frequency of ruminal contractions at 15 micromol/kg per min without altering the amplitude, while it significantly decreased the frequency and amplitude of ruminal contractions at 30 and 60 micromol/kg per min in a dose-dependent manner. Proglumide did not increase contractile activity of the omasum, abomasum and duodenum or the plasma concentration of immunoreactive cholecystokinin (CCK). Application of proglumide at 1-30 mmol/L inhibited bethanechol-induced contraction in both longitudinal and circular muscle strips of the dorsal sac of the rumen. These results suggest that proglumide at a low dose acts indirectly on the rumen as a CCK receptor antagonist to increase the frequency of contractions, whereas at higher doses it inhibits cholinergic-induced contraction of the ruminal muscles or acts as an agonist to inhibit contractions in sheep. Hence, proglumide at high doses seems unsuitable for research or therapeutic use as a CCK receptor blockade in sheep.

Modification of milk fat composition might be desirable to alter manufacturing characteristics or produce low saturated fat dairy products that more closely meet consumer dietary preferences. The aim of this research was to evaluate functional properties of butter oil obtained from milks with fat composition modified by altering the profile of long-chain fatty acids (FA) absorbed from the small intestine of cows. A control and 5 mixtures of long-chain free FA were infused into the abomasum of lactating dairy cows in a 6 x 6 Latin square design with 21-d periods. Treatments were 1) control (no FA infused), 2) mostly saturated FA (C16:C18 = 0.72), 3) low-linoleic palm FA (C16:C18 = 0.85), 4) palm FA (C16:C18 = 0.72), 5) soy FA (C16:C18 = 0.10), and 6) high-palmitic soy FA (C16:C18 = 0.68). All treatments included meat solubles and Tween 80 as emulsifiers. Solid fat content (from 0 to 40 degrees C), melting point, and force at fracture were determined in butter oil. Milk fat from cows infused with palm FA (treatment 4) exhibited functionality equal to or better than control butter oil. Infusion with palm FA increased amounts of triglyceride (TG) fractions with 48, 52, and 54 carbon numbers but decreased TG with 32, 34, 36, and 42 carbon numbers. Infusion with soy FA increased TG with 26, 38, 40, 52, and 54 carbon numbers but decreased TG with 34, 42, and 46 carbons. Infusion of the mostly saturated FA increased TG with 38, 50, 52, and 54 carbon numbers but decreased TG with 32, 34, and 42 carbon numbers. These TG groups were consistently correlated with functional properties of butter oils from different treatments. The content of palmitic acid is important for maintaining functionality in the presence of increased polyunsaturated FA. The composition of milk fat may be able to be optimized through nutritional manipulation of diets for dairy cows if the optimal composition of FA and TG is defined for a particular dairy product.

The rumen has several important physiological functions: absorption, transport, metabolic activity, and protection. To clarify the molecular basis underlying the physiological function of the rumen, reticulum, omasum, and abomasum, we used mRNA differential display to isolate and identify differentially expressed genes in these tissues. We isolated 18 transcripts that coexpressed in the rumen, reticulum, and omasum. Five genes, ribosomal protein 19 (RPS19), basic helix-loop-helix domain containing class B2 (BHLHB2), NADH dehydrogenase flavoprotein 2 (NDUFV2), exosome component 9 (EXOSC9), and ribosomal protein 23 (RPS23), were highly expressed in the rumen of adult Holstein and Japanese Black cattle. Significant differences of expression were observed in the abomasum compared with the rumen, reticulum, and omasum. To investigate the expression pattern of these genes during the neonatal growth stage, the relative levels of gene expression were analyzed in the rumen and abomasum of 3-wk-, 13-wk-, and 18- to 20-mo-old Holstein cattle. The expression level of RPS19 did not change with age in the rumen and abomasum. The levels of BHLHB2, NDUFV2, and EXOSC9 mRNA in the abomasum decreased (P < 0.05) after weaning and declined (P < 0.05) further in adults; in contrast, expression in the rumen was not altered. Interestingly, the levels of RPS23 mRNA in the rumen increased (P < 0.05) after weaning and further increased in the adult; however, the level of expression of this gene decreased (P < 0.05) in the abomasum with weaning and age. This indicates that the 4 tissues, especially the rumen and abomasum, have different developmental pathways after birth and subsequent onset of rumination.

Objective: To determine and compare the abomasal emptying rates in calves suckling milk replacer or an isotonic or hypertonic solution of NaHCO(3) or glucose., Animals: 5 male Holstein-Friesian calves that were < 30 days of age., Procedures: Calves were fed 2 L of milk replacer or isotonic (300 mOsm/L) or hypertonic (600 mOsm/L) solutions of NaHCO(3) or glucose containing acetaminophen (50 mg/kg). Venous blood samples and transabdominal ultrasonographic abomasal dimensions were obtained periodically after feeding, and abomasal luminal pH was continuously monitored by placement of a luminal pH electrode through an abomasal cannula. Abomasal emptying rate was assessed by the time to maximal plasma acetaminophen concentration, ultrasonographic determination of the half-time of abomasal emptying, and the time for luminal pH to return to within 1 pH unit of the preprandial value., Results: Hypertonic NaHCO(3) solution was emptied slower than an isotonic NaHCO(3) solution, isotonic glucose solution was emptied slower than an isotonic NaHCO(3) solution, and hypertonic glucose solution emptied slower than an isotonic glucose solution., Conclusions and Clinical Relevance: An electrolyte solution for oral administration with a high osmolarity and glucose concentration may lead to a slower resuscitation of dehydrated diarrheic calves because such solutions decrease the abomasal emptying rate and therefore the rate of solution delivery to the small intestine. Whether slowing of the abomasal emptying rate in dehydrated diarrheic calves suckling an oral electrolyte solution is clinically important remains to be determined.

Dehydrated calves with diarrhea are routinely given an oral electrolyte solution (OES) by suckling or esophageal intubation. An important issue related to rehydration therapy is the rate of OES delivery to the small intestine. It is widely assumed that the glucose content of the OES does not impact the speed of resuscitation and that fluid administered by esophageal intubation provides a similar resuscitative response to that obtained by suckling. The aims of this study were to compare the abomasal emptying rate in calves suckling an OES containing a high or low glucose concentration and in calves administered a high-glucose OES by suckling or esophageal intubation. Seven male Holstein-Friesian calves were given the following treatments in random order: 2 L of a commercially available high-glucose OES ([glucose] = 405 mM) by suckling or esophageal intubation or 2 L of a commercially available low-glucose OES ([glucose] = 56 mM) by suckling. Abomasal emptying rate was determined by acetaminophen absorption, ultrasonography, and glucose absorption. High-glucose OES rapidly increased plasma glucose concentration after suckling but produced a slower rate of abomasal emptying than did low-glucose OES. Esophageal intubation of high-glucose OES produced the same initial change in abomasal volume as did suckling, but delayed the rate of OES delivery to the small intestine. Our results suggest that suckling a low-glucose OES provides the fastest rate of abomasal emptying and plasma volume expansion, whereas a high-glucose OES provides the most appropriate oral solution for treating hypoglycemic calves.

We determined the abomasal emptying rates of Holstein-Friesian cows at different stages of lactation, with left displaced abomasum (LDA), or immediately after surgical correction of LDA or abomasal volvulus (AV). D-xylose (0.5 g/kg body weight [BW], 50% solution) was injected into the abomasum in healthy cows (group 1, 4-7 days in milk [DIM], n = 7; group 2, 90-120 DIM, n = 7; group 3, > 300 DIM, n = 7) and in cows with LDA (n = 10; group 4). D-xylose was injected into the abomasum during right flank laparotomy in cows with LDA (n = 22; group 5) and cows with AV (n = 15; group 6). The time to maximal serum D-xylose concentration was used as an index of emptying rate. The abomasal emptying rates for cows in groups 1, 2, and 3 were similar, whereas emptying was slower in cows with LDA and in cows after surgical correction of LDA or AV. The abomasal emptying rate of cows with LDA was slowed to a greater extent immediately after surgery, when compared to the rate obtained before surgery. There was no difference in abomasal emptying rate immediately after surgical correction between cows with LDA or AV. The results indicate that the increased incidence of LDA in the first month of lactation is not associated with an intrinsic decrease in abomasal emptying rate in healthy cows. Our findings also demonstrate that surgical correction further slows the emptying rate in cows with LDA.

Background: The gut hormone, ghrelin, is involved in the neuroendocrine and metabolic responses to hunger. In monogastric species, circulating ghrelin levels show clear meal-related and body weight-related changes. The pattern of secretion and its role in ruminant species is less clear. Ghrelin acts via growth hormone secretagogue receptors (GHSR-1a) to alter food intake, fat utilization, and cellular proliferation. There is also evidence that ghrelin is involved in reproductive function. In the present study we used immunohistochemistry to investigate the presence of ghrelin and GHSR-1a in sheep reproductive tissues. In addition, we examined whether ghrelin and GHSR-1a protein expression is developmentally regulated in the adult and fetal ovine testis, and whether there is an association with markers of cellular proliferation, i.e. stem cell factor (SCF) and proliferating cell nuclear antigen (PCNA)., Methods: Antibodies raised against ghrelin and its functional receptor, GHSR-type 1a, were used in standard immunohistochemical protocols on various reproductive tissues collected from adult and fetal sheep. GHSR-1a mRNA presence was also confirmed by in situ hybridisation. SCF and PCNA immunoexpression was investigated in fetal testicular samples. Adult and fetal testicular immunostaining for ghrelin, GHSR-1a, SCF and PCNA was analysed using computer-aided image analysis. Image analysis data were subjected to one-way ANOVA, with differences in immunostaining between time-points determined by Fisher's least significant difference., Results: In adult sheep tissue, ghrelin and GHSR-1a immunostaining was detected in the stomach (abomasum), anterior pituitary gland, testis, ovary, and hypothalamic and hindbrain regions of the brain. In the adult testis, there was a significant effect of season (photoperiod) on the level of immunostaining for ghrelin (p < 0.01) and GHSR-1a (p < 0.05). In the fetal sheep testis, there was a significant effect of gestational age on the level of immunostaining for ghrelin (p < 0.001), GHSR-1a (p < 0.05), SCF (p < 0.05) and PCNA (p < 0.01)., Conclusion: Evidence is presented for the presence of ghrelin and its receptor in various reproductive tissues of the adult and fetal sheep. In addition, the data indicate that testicular expression of ghrelin and its receptor is physiologically regulated in the adult and developmentally regulated in the fetus. Therefore, the ghrelin ligand/receptor system may have a role (endocrine and/or paracrine) in the development (cellular proliferation) and function of the reproductive axis of the sheep.

Abomasal emptying plays an important role in the incidence of digestive problems in calves. Our aim was to evaluate the acetaminophen absorption test (APAT) for characterization of the oroduodenal transit (ODT) of liquid meals in unweaned calves. Six healthy, unweaned Simmental x Red Holstein crossbred calves were involved in the project. The study was performed in three blocks at 3, 6 and 9 weeks of the calves' age. Within blocks, APAT was performed twice at an interval of at least 24 h. Once per each block, liquid transit was carried out with non-coagulating electrolyte solution (NES). The second test within a block was performed either while atropine sulphate was administered (block I), or by feeding a coagulating milk replacer (block II), or by administration of NES by ruminal tube (block III). Data were compared within and among blocks. Significant differences of several APAT traits were present for the different types of feeding, the different types of meals, the administration of atropine sulphate and the different ages of the calves. The emptying index T(max)/C(max) was suggested to be a valuable kinetic parameter for the characterization of ODT in these calves. We conclude that APAT represents a valid technique for characterization of ODT of liquid meals in healthy unweaned calves and may be a valuable tool for the evaluation of the reticular groove mechanism, the abomasal emptying and the absorption capacity of the duodenum.

The objective of this study was to determine whether oral administration of omeprazole, a proton-pump inhibitor, increased abomasal luminal pH in calves fed milk replacer. Four male dairy calves with cannulae in the abomasal body suckled milk replacer (60 ml/kg body weight every 12 h) and were administered a non-enteric-coated omeprazole (4 mg/kg body weight every 24 h) in a paste formulation for five successive days. Abomasal luminal pH was continuously measured using miniature glass pH electrodes. On the first day of omeprazole administration, there was a significant (P<0.05) increase in mean 24-h pH from 2.89 to 4.17. The mean 24-h pH on days 2, 3, 4 and 5 of omeprazole administration were 3.85, 4.02, 3.97 and 3.39 respectively. We conclude that oral administration of non-enteric-coated omeprazole increased abomasal luminal pH in calves fed milk replacer, but that the effect may decrease over time.

Objective: To develop nuclear scintigraphic and acetaminophen absorption methods for measuring abomasal emptying rate in suckling calves., Animals: 9 male Holstein-Friesian calves < 30 days old., Procedure: Calves were fed 2 L of milk replacer, fresh cow's milk, or an isoosmotic (150mM) solution of NaCl, NaHCO3, or sodium acetate containing technetium TC 99m-diethylenetriamine-pentaacetic acid (370 MBq) and acetaminophen (50 mg/kg). Right lateral scintigraphic images and venous blood samples were obtained periodically after feeding. Two power exponential equations were fitted to the scintigraphic data, and 3 pharmacokinetic models were fitted to the acetaminophen concentration-time data., Results: Data from 32 feedings were analyzed, with half emptying time for scintigraphic evaluation ranging from 29 to 202 minutes. Siegel's modified power exponential equation provided a better description of the scintigraphic data than did Elashoff's power exponential equation. The first derivative of Siegel's modified power exponential formula provided the best pharmacokinetic model for the acetaminophen absorption data. Time to maximal acetaminophen concentration (Tmax) provided the most accurate index of abomasal emptying rate from the acetaminophen concentration-time data., Conclusions and Clinical Relevance: Abomasal emptying rate is best determined in healthy suckling calves by use of Siegel's modified power exponential equation to model the scintigraphic data. Pharmacokinetic calculation of Tmax from the acetaminophen absorption curve provides an alternative method for determining abomasal emptying rate in healthy suckling calves that is accurate, inexpensive, practical, and safe. However, it is unclear whether diarrhea would alter the acetaminophen absorption curve in calves.