Abomasal Emptying Research Articles

Fat composition of milk replacer influences postprandial and oxidative metabolisms in dairy calves fed twice daily

Milk replacers (MR) for calves contain alternative fat sources as substitute for milk fat. This substitution leads to differences in fat properties, such as the fatty acid profile and the triglyceride structure. This study evaluated how fat composition in MR affects gastrointestinal health, blood redox parameters, and postprandial metabolism in calves fed twice daily. Forty-five individually housed male Holstein-Friesian calves (2.3 ± 0.85 d of age) were assigned to 1 of 15 blocks based on the age and the day of arrival. Within each block, calves were randomly assigned to 1 of 3 experimental diets and received their respective diet from arrival until 35 d after arrival. The 3 experimental diets (n = 15 per treatment group) consisted of an MR with a blend of vegetable fats containing rapeseed and coconut (VG), an MR with only animal fats from lard and dairy cream (AN), and an MR containing a mixture of animal and vegetable fats including lard and coconut (MX). The fatty acid profile of each MR was formulated to resemble that of bovine milk fat while using only 2 fat sources. All MR were isoenergetic, with 30% fat (% DM), 24% crude protein, and 36% lactose. Chopped straw and water were available ad libitum from arrival onward but no starter feed was provided. Daily milk allowances were 6.0 L from d 1 to 5, 7.0 L from d 6 to 9, and 8.0 L from d 10 to 35, divided into 2 equal meals and prepared at 135 g/L (13.5% solids). Fecal appearance was scored daily; calves were weighed and blood was drawn on arrival and weekly thereafter. Urine and feces were collected over a 24-h period at wk 3 and 5 to determine apparent total-tract digestibility and assess gastrointestinal permeability using indigestible markers. Postprandial metabolism was evaluated at wk 4 by sequential blood sampling over 7.5 h, and the abomasal emptying rate was determined by acetaminophen appearance in blood. Fat composition in MR did not affect growth, MR intake, gastrointestinal permeability, nor nutrient digestibility. The percentage of calves with abnormal fecal scores was lower at wk 2 after arrival in calves fed VG than MX, whereas AN did not differ from the other treatments. Calves fed AN and MX had higher thiobarbituric acid reactive substances measured in serum than VG, whereas plasma ferric-reducing ability was greater in calves fed MX than VG. Postprandial acetaminophen concentrations did not differ across treatment groups, but the area under the curve was smaller in calves fed VG than in the other 2 treatments, which is indicative of a slower abomasal emptying. Postprandial serum triglyceride concentration was greater in calves fed AN than VG, whereas MX did not differ from the other treatments. Based on these outcomes, all 3 fat blends can be considered suitable for inclusion in MR for calves.

Postprandial metabolism and gut permeability in calves fed milk replacer with different macronutrient profiles or a whole milk powder

Significant differences exist in the composition of current milk replacers (MR) and bovine whole milk. This study investigated how the macronutrient profile of 3 different MR formulations containing varying amounts of fat, lactose, and protein, and a whole milk powder (WP), affect postprandial metabolism and gut permeability in male Holstein calves. Sixty-four calves (45.4 ± 4.19 kg [mean ± SD] and 1.8 ± 0.62 d of age) were blocked in order of arrival to the facility and within each block, calves were randomly assigned to 1 of 4 treatments. Treatments included a high-fat MR (HF: 25.0% dry matter [DM] fat, 22.5% protein, 38.6% lactose; n = 14), a high-lactose MR (HL: 44.6% lactose, 22.5% protein, 18.0% fat; n = 17), a high-protein MR (HP: 26.0% protein, 18.0% fat, 41.5% lactose; n = 17), and WP (26.0% fat, 24.5% protein, 38.0% lactose; n = 16). Calves were fed 3.0 L (135 g/L) 3 times daily at 0600, 1200, and 1800 h with a teat bucket. Milk intake was recorded daily for the first 28 d after arrival, and blood sampling and body weight measurements were performed at arrival and on d 7, 14, 21, and 27. Gut permeability was estimated from fractional urinary excretion of indigestible markers (Cr-EDTA, lactulose, and d-mannitol) administered as a single dose on d 21 instead of the morning milk meal. Digestibility was determined simultaneously from a total collection of feces over 24 h. Postprandial dynamics were measured on d 28 by sequential blood sampling over 7.5 h. Dry matter intake of MR over 28 d was slightly greater in calves fed HL and HP than in WP. Recovery of Cr-EDTA and d-mannitol over a 24-h urine collection was greater in calves fed WP and HP than HL calves. Apparent total-tract digestibility of crude ash, protein, and fat did not differ among treatments; however, DM digestibility was lower in calves fed WP than in other treatment groups. In addition, abomasal emptying, as indicated by the area under the curve (AUC) for acetaminophen, was slower in calves fed WP than in calves fed HF and HL. The AUC for postprandial plasma glucose was lower in calves fed HL than WP and HF and lower in calves fed HP than WP. The AUC for postprandial serum insulin was greater in calves fed HP than WP and HF, whereas calves fed HL did not differ from the other treatments. Postprandial triglycerides were greater in calves fed WP, and postprandial adiponectin was higher in calves fed HL than other treatments. The high content of lactose and protein in MR had a major effect on postprandial metabolism. This raises the possibility of optimizing MR formulations to maintain metabolic homeostasis and influence development.

Effect of erythromycin on abomasal emptying in suckling lambs with experimental endotoxemia

Abomasal hypomotility and consequently a decrease in abomasal emptying rate is one of the most important factors in ruminant abomasal disorders. Endotoxemia is clinically recognized by abnormalities in cardiovascular function, renal failure, decreased gastrointestinal motility and shock. This can lead to bloating and sudden death in lambs that have not received enough colostrum. The aim of the study was to investigate the effect of erythromycin treatment on abomasal emptying rate in endotoxemic lambs. Fifteen suckling lambs arranged in 3 groups (n = 5) were studied in this study. Endotoxemia was induced in two groups (Positive control and Erythromycin) at 0.1 μg/kg body weight LPS in 10 mL normal saline over 5 min IV and erythromycin was injected to erythromycin group at 8.8 mg/kg BW IM. Negative control received 2 mL normal saline IM. Abomasal emptying rate was assessed by acetaminophen absorption test, which was fed with milk at 50 mg/kg BW, 30 min after each treatment. Samples were collected at 15 min intervals up to 240 min and abomasal emptying rate was assessed for each group. Results showed there were significant differences in Cmax, Tmax and AUC among groups (endotoxemia groups and control group) (P < 0.05), confirming a decrease in abomasal emptying rate in lambs with endotoxemia. The results also indicated that compared to affected lambs not treated with erythromycin, abomasal emptying rate was significantly higher in lambs treated with erythromycin that means erythromycin increased abomasal emptying rate (P < 0.05).

Effects of milk replacer feeding rate and frequency of preweaning dairy calves in the southeastern United States: Performance, abomasal emptying, and nutrient digestibility

To evaluate the effects of milk replacer (MR) feeding rate (FR) and frequency (FF) on performance, abomasal emptying, and nutrient digestibility in the southeastern United States, Holstein calves (n = 48/season) were enrolled at 8 d of age (DOA) during summer [June to August, body weight (BW; mean ± SD) = 40.71 ± 4.35 kg] and winter (November to January, BW = 42.03 ± 3.83 kg). Within season, calves were randomly assigned to 1 of 4 treatments in a 2 × 2 factorial arrangement including 2 FR [0.65 (low) or 0.76 kg of solid per day (high) of a 26% crude protein and 17% fat MR], and 2 FF [2× (0700 and 1600 h) or 3× (0700, 1600, and 2200 h) daily]. Calves were housed in polyethylene hutches and managed similarly throughout the trial. Milk replacer (12.5% solids) was fed to calves based on their respective treatments until 42 DOA, when MR allowance was reduced by 50% and offered once a day (0700 h) for the following 7 d until weaning. Calves remained on trial until 63 DOA. Calf starter and water were offered ad libitum. Ambient temperature and relative humidity inside and outside hutches were measured hourly. Starter and MR intakes were recorded daily. Respiration rate and rectal temperature were recorded 3 times a week. Structural growth and BW were measured weekly. Acetaminophen (50 mg/kg of BW) mixed with MR was fed to a subset of calves (0700 h, n = 10/treatment per season) on 20 DOA. Plasma was collected at 15, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 360, 420, and 480 min after feeding, to analyze acetaminophen. The acetaminophen concentration-time curve was modeled to the first derivative of Siegel's modified power exponential equation, and the time for plasma acetaminophen to reach maximum (Tmax) was calculated to evaluate abomasal emptying rate. During the pre- (14.9-17.9 DOA) and postweaning (51.0-54.0 DOA) periods, a subset (n = 8/treatment per season) of calves was used to determine the apparent digestibility of nutrients, using chromic oxide as the external marker. Feeding 3× reduced preweaning respiration rate during summer and reduced rectal temperature during winter. Increasing FR improved BW gain and structural growth. Feeding more times per day tended to improve growth during winter but not summer. We found no effect of treatment on nutrient digestibility. Increasing FR had no effect on Tmax during winter but tended to delay Tmax of plasma acetaminophen during summer. Regardless of season, increasing FF lowered Tmax of plasma acetaminophen. In conclusion, increasing FF accelerated abomasal emptying and might reduce heat load of preweaning dairy calves but improved growth only during winter. Increased MR allowance improved growth in both seasons but delayed abomasal emptying only under heat stress conditions.

Schmallenberg virus infection suspected in a calf born to an imported heifer.

Schmallenberg virus infection suspected in a calf born to an imported heifer.

Effects of energy source in milk replacer on glucose metabolism of neonatal dairy calves

Milk replacers (MR) formulated to contain more lactose than whole milk could potentially reduce insulin sensitivity in dairy calves. This study evaluated how partially replacing lactose in MR with fat on a weight/weight basis affects glucose-insulin kinetics in neonatal dairy calves fed high quantities of MR. Thirty-four Holstein bull calves were blocked by dam parity (1.6 ± 0.3) and randomly assigned to 1 of 2 treatments (n = 17): a high-lactose MR (HL; 46.1% lactose, 18.0% crude fat, and 23.9% crude protein on a dry matter basis) or a high fat MR (HF; 39.9% lactose, 24.6% crude fat, and 24.0% crude protein on a dry matter basis). Calves were individually housed and fed pooled colostrum at 1.5 h and 12 h postnatal at 18 and 9% of metabolic body weight (BW0.75), respectively. From 24 h postnatal until the end of the study (d 7), calves were transitioned to MR (prepared at 150 g/L) at 18% of BW0.75 twice daily at 0700 and 1900 h. On d 4, an insulin-modified intravenous glucose tolerance test was conducted 8 h after the morning meal by intravenous infusion of glucose (0.54 g/kg of BW0.75, min 0) and insulin (3.9 µg/kg of BW0.75, min 20). During postprandial sampling on d 6, abomasal emptying was assessed by dosing acetaminophen (0.13 g/kg of BW0.75) with MR and measuring its appearance within plasma. Sequential blood samples were collected and analyzed for plasma glucose, insulin, and acetaminophen concentrations. Calves were killed on d 7 and liver and pancreatic tissues were collected for histomorphological analysis. Partially replacing lactose in MR with fat increased body weight gain (679.6 vs. 462.0 ± 69.68 g/d) and gain:metabolizable energy intake (186.6 vs. 120.5 ± 20.21 g of body weight/Mcal) compared with feeding HL MR. Furthermore, abomasal emptying rate was reduced in calves fed HF MR. Calculated variables based on postprandial glucose and insulin concentrations, such as maximum concentration or area under the curve, were or tended to be lower in HF than in HL calves. Postprandial insulin sensitivity tended to be reduced in HL compared with HF, although insulin sensitivity estimated from the insulin-modified intravenous glucose tolerance test was not different. Calves fed HF MR showed enhanced glucose-stimulated insulin secretion. In conclusion, partially replacing lactose in MR with fat resulted in smaller fluctuations in postprandial glucose and insulin concentrations and tended to increase postprandial but not fasting insulin sensitivity in neonatal dairy calves.

The Effect of Oral Administration of Turmeric (Curcuma longa) Aqueous Extract on Abomasal Emptying Rate in Neonatal Lambs

زمینۀ مطالعه: کاهش حرکات شیردان نقش مهمی در بیماریزایی برخی اختلالات شیردانی همچون نفخ شیردان ایفاء می‌کند که درمان آن با داروهای سنتتیک عوارضی مانند اسهال و مقاومت آنتی‌بیوتیکی دارد و تجویز داروهای گیاهی راهکار مناسبی برای کاهش این عوارض جانبی است. هدف: تعیین اثر تجویز خوراکی عصاره آبی زرد چوبه برسرعت تخلیه شیردان در بره‌های نوزاد. روش‌کار: این مطالعه بر روی 12 بره ماده پنج روزه نژاد سنگسری انجام گرفت (میانگین وزن 3کیلوگرم). همه بره‌ها به ترتیب پنج درمان خوراکی شامل سالین (30میلی‌لیتر)، اریترومایسین (400میلی‌گرم)، زردچوبه 200 میلی‌گرم بر کیلوگرم، زردچوبه 250میلی‌گرم بر کیلوگرم و زردچوبه 300 میلی‌گرم بر کیلوگرم را دریافت کردند. در دقایق صفر30،60،،120، 150، 180 و 240 پس از هر درمان نمونه پلاسما از بره‌ها اخذ گردید و با استفاده از تست جذب استامینوفن سرعت تخلیه شیردان تعیین شد. نتایج: درمان با اریترومایسین و سه دز متفاوت عصاره آبی زردچوبه (200، 250 و 300 میلی‌گرم بر کیلوگرم) نسبت به درمان کنترل منفی سبب افزایش معنی‌دار سرعت تخلیه شیردان گردید (05/0>P). اثر تحریکی اریترومایسین در تخلیه شیردان به صورت معنی‌داری از عصاره آبی زردچوبه بیشتر بود (05/0>P). هیچ گونه عارضه جانبی‌ بالینی به دنبال تجویز اریترومایسین و زردچوبه در بره‌ها مشاهده نشد. نتیجه‌گیری نهایی: این پژوهش نشان داد که عصاره‌ی آبی زردچوبه اثر تحریکی بر تخلیه شیردان بره دارد اما به مطالعات بیشتری درزمینه‌ی اثر اجزای این گیاه بر تخلیه شیردان نیاز است.

404 Awardee Talk - Healthy gut, healthy calf, productive life

Abstract The calf undergoes major transformations in early life that make it more susceptible to gastrointestinal tract (GIT) disease and disorders compared to all herd-mates. One of the most critical management factors in calf survival and health is feeding a sufficient amount of high-quality colostrum in order to improve passive transfer. However, further benefits to GIT function and health are now also being recognized. It has recently been shown that a delay in colostrum feeding of only six or twelve hours after birth can impact not only passive transfer but also the colonization of healthy bacteria (Bifidobacterium) in the small intestine of newborn calves. In addition, the heat treatment of colostrum has been shown to increase the colonization of Bifidobacterium and decrease the colonization of Escherichia coli in the small intestine of calves during the first 12 hours of life. New research is showcasing how the transition from colostrum to milk in the first days of life is critical to GIT development. For example, calves that transition directly to milk after the first meal of colostrum have less overall GIT mass and small intestinal villi development compared to calves fed transition milk or colostrum at three days of life. Based on these preliminary findings, there is a need to consider other bioactive components in colostrum and transition milk that impact GIT development in order to provide the calf with the best chance to combat GIT ailments later in life. With respect to the pre-weaning period of calf production, the amount of milk to be fed to calves has been a hot topic in the past decade, as it directly impacts pre-weaning average daily gain, which may be associated with lifetime production. Most dairy calves are only fed two meals per day and it is thought that increasing meal sizes may cause milk overflow into the rumen, resulting in digestive upsets and hyperglycemia. What recent research has shown however is that the GIT of the calf has a certain degree of plasticity and can adapt to large meal sizes (10% of birth bodyweight) in the first weeks of life by altering abomasal emptying as a means of controlling nutrient delivery to the intestine, thereby stabilizing blood metabolites such as glucose. In addition, new research investigating milk replacer composition, which is higher in lactose and lower in fat compared to whole milk, shows differences in abomasal function that may lead to a negative impact on insulin sensitivity. This research suggests that we have been underestimating how much milk calves can consume and how new milk replacer formulations may be impacting GIT health. An improved understanding of how diet, microbiota, and biomolecules interact to impact growth and barrier function of the calf’s GIT would greatly benefit the industry. A mechanistic understanding of such adaptations would also aid in the formulation of specific management regimens and the provision of diets that support or enhance gut function in young calves.

Effect of replacing lactose with fat in milk replacer on abomasal emptying and glucose–insulin kinetics in male dairy calves

ABSTRACT Objective Altering energy supply and the relative proportions of energy source in the first weeks of life of dairy calves may influence glycemic and insulinemic responses. The objective of this study was to assess the metabolic responses to high-lactose or high-fat milk replacer. Materials and Methods Forty male calves were fed 7 L of milk replacer per day in 2 meals given 10 h apart, considered either high lactose (44% lactose, HL) or high fat (37% lactose, HF), from the first week of life to 30 d of age. Postprandial blood plasma glucose, insulin, and acetaminophen (an abomasal emptying marker) concentrations were measured up to 420 min and used to fit a mathematical model of abomasal emptying and glucose–insulin dynamics. Additionally, an i.v. glucose tolerance test was used to assess glucose tolerance and insulin sensitivity. Results and Discussion Insulin sensitivity remained unchanged; however, glucose maximal concentration and change from baseline tended to be greater for HL in response to an i.v. glucose challenge. Postprandial glucose was elevated at 30 min for HL and HF at 60 and 90 min. Model parameterization showed no difference in abomasal emptying; however, intestinal glucose absorption tended to be faster with HL. Potentiation of insulin action was greater with HL, and pancreatic responsiveness tended to be greater with HF. Implications and Applications These results suggest HL increased early-phase postprandial glucose appearance, which may influence insulin action. In this study, modifying milk replacer composition to more closely resemble cow’s milk did not negatively affect glucose metabolism.

The sites in the duodenum of receptor areas which affect abomasal emptying in the calf

Calves were prepared with abomasal and duodenal cannulae to assess the effects on abomasal emptying of duodenal infusates at different rates and different sites. In two calves infusions of isotonic NaHCO3 or 60 mM HCl 30 cm distal to the pylorus were as effective in controlling abomasal emptying as infusions of the duodenum from 5 cm distal to the pylorus, and in three other calves they were as effective as perfusing the whole duodenum including the most proximal 5 cm. Reducing the rate of duodenal infusion of 60 mM HCl from 10 to 2.5 ml/min diminished its effect from total inhibition of gastric emptying to slight or negligible inhibition. The stimulation of gastric emptying by duodenal infusion of isotonic NaHCO3 solution was undiminished by reduced rates of infusion. It is proposed that in the calf receptors which activate and inhibit gastric emptying are present throughout the duodenum.

The effect of tube versus bottle feeding colostrum on immunoglobulin G absorption, abomasal emptying, and plasma hormone concentrations in newborn 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.

The effect of the endotoxemia on the abomasal emptying rate in suckling lambs as shown by acetaminophen absorption test

Abomasal hypomotility and a decreased rate of abomasal emptying are believed to play important roles in the etiopathogenesis of abomasal disorders in ruminants. The abomasal emptying rate is potentially influenced by several factors. Effect of endotoxins on contractility of smooth-muscle preparations from the bovine abomasal antrum has been evaluated, and the results showed that endotoxemia has an inhibitory effect on contractility of abomasal smooth-muscle fibers. To evaluate the effect of the endotoxemia on the abomasal emptying rate in suckling lambs, this study was conducted. This study was done on five suckling lambs in two phases. In phase 1 (control group), the first blood sample was obtained in 7 a.m. (time zero). Then a mixture of milk, barium sulfate 70%, and acetaminophen was administered orally to each lamb. Afterwards, blood samples were obtained each 15 min up to 4 h later. Phase 2 (treatment group) was similar to phase 1, but after the first blood sampling in time zero in 7 a.m., endotoxemia was induced by administration of commercial lipopolysaccharide at dose rate of 2 μg/kg. The rest of the processes of phase 2 were similar to phase 1. Cmax, Tmax, and area under concentration curve (AUC) of acetaminophen were measured in the control and treatment groups. The abomasal emptying rate was assessed by comparing Cmax, Tmax, and AUC of acetaminophen between the control and treatment groups. The data from the control and treatment groups were analyzed statistically by SPSS program, using one-way ANOVA. Results indicated that Cmax, Tmax, and AUC in the endotoxemic (treatment) group were significantly different compared with those in the control group, which means endotoxemia decreased abomasal emptying rate. Results of present study indicated that endotoxemia profoundly decreases the abomasal emptying rate in suckling lambs. Thus, administration of drugs which attenuate endotoxemia could enhance the abomasal emptying rate in endotoxemic animals.

Measurement of abomasal conditions (pH, pressure and temperature) in healthy and diarrheic dairy calves using a wireless ambulatory capsule

This study investigated abomasal luminal parameters in healthy and diarrheic calves by using a wireless ambulatory capsule (WAC). The acetaminophen absorption test (APAT) was used to determine abomasal emptying rate. Four healthy and five diarrheic female Holstein-Friesian calves (age < 14 days) were included in the study. For APAT, calves were fed 2L of milk replacer containing 50mg acetaminophen/kg body weight, and blood samples were taken during a 12-h period afterward. Concomitantly, a WAC in the abomasum continuously measured luminal pH, pressure, and temperature. Five hours post suckling, intraluminal temperature was significantly higher in diarrheic calves than in healthy calves. Abomasal pH and pressure were not significantly different, but intraluminal pressure was always numerically lower in diarrheic calves. During APAT no significant differences in maximum acetaminophen concentrations (Cmax) and time to reach maximum acetaminophen concentration (Tmax) were observed. Nonlinear regression findings revealed a longer acetaminophen half-time (AAP t1/2) in diarrheic calves compared to healthy calves [564 ± 96min vs. 393 ± 84min, respectively; P = 0.04] and lower area under the concentration curve values (e.g., 60min postprandial AUC60 681 ± 244 (µg∙min)/mL vs. 1064 ± 23 (µg∙min)/mL, respectively; P = 0.04). In conclusion, abomasal luminal conditions were different between diarrheic and healthy calves. Significant differences in APAT reflected a delay in abomasal emptying in diarrheic calves. Impaired abomasal movement may induce enhanced bacterial fermentation processes as indicated by a higher abomasal temperature in diarrheic calves, which should be considered in management of their feeding.

Short communication: Parameters of abomasal emptying and glucose-insulin dynamics in Holstein-Friesian calves at 2 ages and 2 levels of milk replacer intake

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.

Invited review: Abomasal emptying in calves and its potential influence on gastrointestinal disease

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.

Effect of plane of milk replacer intake and age on glucose and insulin kinetics and abomasal emptying in female Holstein Friesian dairy calves fed twice daily

The objective of this study was to investigate how preweaning plane of milk replacer intake and age can affect insulin and glucose kinetics as well as abomasal emptying rate in dairy calves fed twice a day. A total of 12 female Holstein Friesian calves were blocked by cow parity, paired by colostrum origin, and were randomly assigned to a high plane of milk replacer intake (8 L/d, 1.2kg of milk replacer/d; n=6) or a low plane of nutrition (4 L/d, 0.6kg of milk replacer/d; n=6). All calves received 4 L of colostrum over 2 meals (1 and 6h after birth) and were then directly transferred to their assigned feeding plans until they were stepped-down from milk by 50% during wk 7 and weaned on wk 8. Milk replacer (24% crude protein, 18% crude fat) was fed at 150g/L twice daily (0700 and 1700h) and all calves had ad libitum access to pelleted calf starter, chopped wheat straw, and water. Jugular catheters were placed in all calves at 4, 7, and 10wk of age. Then, postprandial response to plasma glucose, insulin, and acetaminophen (supplied with the meal) were determined to measure abomasal emptying. The next day, a glucose tolerance test was conducted by infusing glucose via the jugular catheter. At 4 and 7wk of age, the rate constant (%/h) for abomasal emptying of the meal was lower in high calves (0.21±0.02 in wk 4; 0.27±0.02 in wk 7) compared with low (0.34±0.02 in wk 4; 0.47±0.02 in wk 7). The postprandial plasma insulin area under the curve over 420min was greater in high calves (18,443±7,329; low=5,834±739 µU/mL) compared with low. We found no differences in glucose tolerance test kinetics between the high and low dairy calves at 4, 7, or 10wk of age. The findings from this study suggest that feeding dairy calves an elevated plane of nutrition in 2 meals of milk replacer per day does not decrease insulin sensitivity.

Effects of wheat protein in milk replacers on abomasal emptying rate in calves.

Diarrhoea is a condition with tremendous impact on calf health. Infectious agents play a dominant role; however, non-infective factors may also contribute to pathogenesis of diarrhoea. One factor, the abomasal emptying rate, is mainly influenced by the composition of feed. The aim of the study was to assess the influence of different protein sources in milk replacers on abomasal emptying rate and clinical parameters. The effect of increasing age of the calves on abomasal emptying was also evaluated. The study compared abomasal emptying rates and clinical parameters in calves, which were fed either milk replacer containing only whey protein or one which partially contained wheat protein. Abomasal emptying rate was estimated by ultrasonography. Ten calves were used in the study over 18days, and each calf was fed 3 periods of 3days length using different milk replacers in an alternating crossover design. The abomasum was emptied significantly faster when the wheat protein containing milk replacer was fed (half-emptying time wheat protein 49.1±4.1min, half-emptying time milk protein 59.1±7.4min); however, clinical parameters and weight gain did not differ between the feeding regimes. Age did not significantly influence abomasal emptying rate. As milk replacers containing wheat proteins increased abomasal emptying rate, they may have a higher potential to initiate diarrhoea, especially if high volumes are fed. Thus, the feeding regimes are likely to be even more important when such milk replacers are used.

Ultrasonographic imaging of abomasal milk clotting and abomasal diameter in healthy and diarrheic calves.

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.

Effect of abomasal emptying rate on the apparent efficiency of colostral immunoglobulin G absorption in neonatal Holstein-Friesian calves

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, 2mL of 0.9% NaCl intramuscularly; erythromycin, 8.8mg/kg of body weight intramuscularly; ivermectin, 200μg/kg intravenously; and gentamicin, 6.6mg/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 3L of pooled cow colostrum containing acetaminophen (50mg/kg of body weight) by oroesophageal intubation at 1h of age and 30min 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 (R2=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.

Change of plasma volume, osmolality, and acid–base status in healthy calves after feeding of milk and water- and milk-based oral rehydration solutions

Oral rehydration solutions (ORS) are a simple and cheap method to treat diarrheal dehydration and acidosis. To maintain the energy supply of diarrheic calves, it is necessary to continue milk feeding. Suckling of milk or milk-based or hypertonic water-based ORS produces a slower rate of abomasal emptying than suckling isotonic water-based ORS. The faster abomasal passage of isotonic water-based ORS implies that efficacious electrolytes reach the gut more quickly, possibly providing a faster rate of rehydration. The aim of the study was to verify when and to what extent milk and water- and milk-based ORS increase plasma volume and affect plasma osmolality and acid–base status in healthy suckling calves. Eleven calves were fed with milk and with an ORS that was prepared in water or milk. Moreover, for one experiment, the calves remained fasting without suckling milk or ORS. During the experimental phase, the calves were deprived of water, hay, and concentrates. Blood samples were taken before and at various time points after feeding. Total plasma protein, osmolality, [Na+], [K+], [Cl−], and albumin were determined. In 6 of 11 experiments, blood gas analysis was also performed. The calculated change in plasma volume after feeding was assessed from the plasma protein concentration before feeding (Pt=0) and the plasma protein concentration after feeding (Pt=x): (Pt=0− Pt=x) × 100/Pt=x. Water- and milk-based ORS produced equal rates of plasma expansion in healthy calves. After milk feeding, the change in plasma volume was decelerated. Because of water influx, we did not observe a significant effect of feeding regimen on plasma osmolality. Acid–base status was little affected by feeding regimen. Feeding of milk-based ORS increased plasma strong ion difference, an alkaline response, which could potentially also reduce acidosis in calves suffering from diarrhea.