Outbreaks of dermatopathy caused by Tephrosia noctiflora intoxication in Brazilian cattle.

This study aims to update the knowledge concerning the intoxication by Tephrosia noctiflora in Brazilian cattle herds by reporting new cases of intoxication in lactating cows, their calves and bulls and highlight the epidemiology, clinical signs, pathogenesis, gross, and microscopic lesions. The morbidity and mortality of this intoxication in the farms studied was low. Gross lesions in all affected cattle consisted of dermatitis with hyperpigmentation, crusts, ulceration, erythema, and lichenification in the skin of limbs, ventral abdomen, perianal and perineal areas of lactating calves and adult cattle. Microscopically, the main lesion observed consisted of severe dermatitis with parakeratotic hyperkeratosis, papillated proliferation, and diffuse, accentuated lymphoplasmacytic inflammatory infiltrate in the epidermis and dermis. The presence of skin lesions mainly in the limbs and ventral abdomen of cattle implies the pathogenesis of intoxication is related to a primary contact dermatitis, and the occurrence of similar lesions on the skin of nursing calves reinforces this hypothesis. The putative toxins of T. noctiflora have been thought to be rotenoids. Additional work is needed to define better if these compounds are the main toxin responsible for the dermatopathy observed in these herds.

MNQ derivative D21 protects against LPS-induced inflammatory damage in bovine ovarian follicular GCs in vitro via the steroid biosynthesis signaling pathway.

Bacterial infections of the reproductive system of dairy cows lead to inflammation, and lipopolysaccharide (LPS) of the cell wall of Gram-negative bacteria is the main pathogenic component of inflammation. LPS inhibits follicular growth and development and alters the expression of follicular granulosa cells (GCs) genes in the ovary, leading to their functional disorders. Naphthoquinones have anti-inflammatory effects. In this experiment, 2-methoxy-1,4-naphthoquinone (MNQ), an extract of Impatiens balsamina L, and its derivative D21 were used to eliminate the inflammatory response of GCs exposed to LPS in vitro and to restore functional disorders in GCs. The anti-inflammatory effects of the two compounds were compared and their mechanism of action was investigated. The cytotoxicity of MNQ and its derivative D21 on follicular GCs was determined by MTT method. The relative expression of inflammatory factors and steroid synthesis-related genes were determined by qRT-PCR. The protective effects of MNQ and D21 on cellular inflammatory damage were observed by TEM. ELISA were performed to detect the levels of estradiol (E2) and progesterone (P4) in the culture supernatant. The expression of differential genes was analyzed by RNA-seq, and GO and KEGG enrichment analysis of differential genes were performed to investigate the mechanism of anti-inflammatory effect of D21. The results showed that the maximum no-cytotoxic concentrations of MNQ and D21 acting on GCs for 12 h were 4 µM and 64 µM, respectively. LPS concentration of 10 µg/mL had little effect on the survival of follicular GCs, but the relative expressions of IL-6, IL-1ß and TNF-α were significantly higher (P < 0.05). The results of qRT-PCR, ELISA and TEM observations showed that the anti-inflammatory effect of D21 was stronger than that of MNQ. RNA-seq analysis revealed a total of 341 differential genes between the LPS vs CK group (Control group) and the D21+L vs LPS group, which were mainly enriched in signaling pathways such as steroid biosynthesis. Nine genes in this signaling pathway were analyzed, and the RNA-seq and qRT-PCR results were found to be basically consistent. In this study, we confirmed that derivative D21 has stronger in vitro anti-inflammatory effects and better efficacy in protecting bovine follicular GCs from inflammatory damage than MNQ and acts through the steroid biosynthesis signaling pathway.

Lantana camara poisoning in cattle that took refuge during a storm in a forest invaded by this plant.

An outbreak of poisoning by Lantana camara occurred in cattle when a herd sought refuge in a Eucalyptus forest heavily infested by this plant. The animals showed apathy, elevated serum activities of hepatic enzymes, severe photosensitivity, jaundice, hepatomegaly and nephrosis. After a clinical manifestation period of 2-15 days, 74 out of 170 heifers died. The main histological changes were random hepatocellular necrosis, cholestasis, biliary proliferation and, in one animal, centrilobular necrosis. Immunostaining for Caspase 3 detected scattered apoptotic hepatocytes.

Eucalcemia during lipopolysaccharide challenge in postpartum dairy cows: II. Calcium dynamics.

Hypocalcemia induced by immune activation is a conserved response among mammals. Early postpartum cows will experience decreased circulating Ca concentrations following acute immune activation; however, the cause for decreased Ca concentration is unknown. Our objectives were to (1) describe Ca dynamics following an intravenous (IV) LPS challenge in early postpartum cows, and (2) compare inflammatory-induced changes in Ca dynamics between IV Ca-treated cows and control cows. Cows (n = 14, 8 ± 1 d in milk) were enrolled in a matched-pair randomized controlled design to receive IV Ca (IVCa) in a eucalcemic clamp for 12 h, or 0.9% NaCl (CTRL) following an IV LPS infusion (0.040 or 0.045 µg of LPS/kg of body weight over 1 h). During the 24 h following LPS infusion, circulating concentrations of parathyroid hormone and serotonin were measured, serum and urine samples were collected to calculate urinary fractional excretion of Ca (FECa), and fecal samples were collected to calculate Ca apparent digestibility (ADCa) using amylase-treated and ash-corrected undigested neutral detergent fiber after 240 h (uNDFom240) as an internal marker. Changes in Ca intake and milk Ca secretion were also quantified and compared with baseline values. Cows were fasted during challenge and dry matter intake was 20 ± 5% less than baseline values on the day of challenge and did not differ between groups. On the day of challenge, milk Ca concentration increased, but milk yield decreased such that total Ca secreted in milk did not change from baseline. Urine FECa was low overall, but an interaction of treatment and time was identified such that FECa increased in IVCa but decreased in CTRL. Concentrations of parathyroid hormone increased and serotonin decreased following challenge. Fecal dry matter decreased from baseline, but did not differ between 6, 12, and 24 h, and did not differ between groups. An interaction of treatment and time was identified for ADCa and apparent digestibility of dry matter such that digestibility was decreased in CTRL but not IVCa at 6 h. Acute immune activation induced hypocalcemia in CTRL, and although urinary Ca excretion was not a primary cause, it is unclear to what degree hypocalcemia was due to altered ADCa. Eucalcemia appeared to alter adaptations in Ca homeostasis during immune activation as FECa was increased in IVCa animals.

Forsythin inhibits ß-hydroxybutyrate-induced oxidative stress in bovine macrophages by regulating p38/ERK, PI3K/Akt, and Nrf2/HO-1 signaling pathways.

Ketosis is a metabolic disease of dairy cows in the perinatal period, ß-hydroxybutyrate (ß-HB) is the main component of ketosis. High levels of ß-HB can trigger oxidative stress and inflammatory response in dairy cows, leading to decreased milk yield and multiple postpartum diseases. Forsythin (FOR), the major constituent of the herbal medicine Forsythia, has anti-inflammatory, anti-oxidant, and antiviral effects. FOR was demonstrated to have an antioxidant effect on PC12 cells. However, the effects of FOR on ß-HB-stimulated bovine macrophages (BMs) has not been reported. Thus, the aim of the present study was to investigate the effects of FOR on ß-HB-stimulated BMs. Firstly, the CCK8 test confirmed that FOR (50, 100, 200 µg/mL) has no effect on BMs activity, and we selected these concentrations for subsequent experiments. Secondly, through detecting the oxidation indexes ROS, MDA and antioxidant indexes CAT and SOD, we confirmed the antioxidant effect of FOR on BMs. Next, qRT-PCR confirmed that FOR dramatically reduced the mRNA levels of IL-1ß and IL-6. Furthermore, the western blotting confirmed that FOR observably down-regulated ß-HB-stimulated phosphorylation of p38, ERK and Akt and up-regulated expression of Nrf2, and HO-1. Above results suggested that FOR plays antioxidant effects on ß-HB-induced BMs through p38, ERK and PI3K/Akt, Nrf2 and HO-1 signaling pathways. Therefore, we speculated that FOR may be a potential medicine to alleviate ß-HB-induced inflammatory response and provide a preliminary reference for the research and development of FOR.

An acute case of Pimelea elongata toxicity in cattle in western New South Wales.

In May 2019, 96 cattle died from Pimelea toxicity in a period of 19 days after potential exposure, with the first deaths occurring within 5 days. After examining the circumstances, we suspect that several factors contributed to the deaths. These included that recently purchased stock and transported had access to flooded land containing Pimelea elongata. This weed species contains simplexin and 18 other compounds. Roots, flowers and seeds are significantly more toxic than the stem, branches and leaves. We suspect that thirsty and hungry stock consumed seed and roots from flooded pastures and consumed lethal doses of simplexin. Blood tests were not good indicators of the conditions. Management strategies are suggested.

Ethylene glycol toxicosis in milk-fed dairy calves.

BACKGROUND: Ethylene glycol (EG) (antifreeze) toxicosis has mostly been reported in dogs and cats, while reports on EG toxicosis in cattle are sparse. We report EG toxicosis in 25 milk-fed calves associated with a leak in the cooling pipes in a milk taxi. The milk taxi was connected to a geothermal heating system in which EG was used as antifreeze. CASE PRESENTATION: Although the assistant responsible for feeding milk to the calves observed a few blue-colored droplets of liquid on the surface of the milk in the milk taxi and suspected EG contamination, the milk was fed to the calves. Within hours, the calves became depressed and some died within the next 2 days. Necropsy and histopathology revealed widespread severe acute renal tubular necrosis with numerous birefringent crystals in the tubular lumen. Biochemical analysis of serum showed severe damage to the kidneys (marked azotemia) and hypochloremia, hyponatremia and hyperkalemia; findings consisting with metabolic acidosis. After feeding the calves, the assistant inspected the milk taxi and found a leaking cooling pipe. CONCLUSIONS: The suspected EG toxicosis was confirmed by the observation of renal tubular necrosis, numerous intratubular crystals, and metabolic acidosis. EG toxicosis due to leaking pipes connected to a geothermal heating system has not been reported previously. Alternative antifreeze products that are less toxic than EG are recommended for use if there is a risk of contamination of human and animal foodstuffs in case of a leak in the system.

Acute hemorrhage and death in calves following chlorophacinone exposure.

Three calves were submitted to the Iowa State University Veterinary Diagnostic Laboratory for diagnostic evaluation following an abrupt increase in morbidity and mortality in a calf herd associated with epistaxis and widespread hemorrhage. Each of the submitted calves had moderate-to-severe hemorrhage within various tissues and body cavities, including the thymus, subcutaneous region of the neck, mediastinum, lungs, pericardial sac, heart, spleen, perirenal fat, urinary bladder, and skeletal muscle, including the diaphragm. An anticoagulant rodenticide screen was performed on the livers of each calf. Significant concentrations of chlorophacinone were detected at 4.2, 3.6, and 2.9 ppm in liver. Multiple piles and an open pail of white powdery material were present within the facility in which the calves were housed and were identified as the sources of chlorophacinone. Acute hemorrhage and death occurred in fourteen 1.5-mo-old, crossbred calves following ingestion of the vitamin K antagonist chlorophacinone.

Nierembergia rivularis poisoning in cattle.

Nierembergia rivularis causes enzootic calcinosis (EC) in sheep. In this work, we describe EC caused by N. rivularis in cattle. For 3 years cattle grazing in 7 paddocks were evaluated. Cows with clinical signs compatible with EC were detected in only one paddock with a morbidity of 9.4%, 24.5%, and 34.5% during the summer of 2019, 2020, and 2021, respectively. Affected cows weighed 55 kg less (p < 0.01) than cows without signs of the same paddock, and 19.6% of these cows had hypercalcemia and/or hyperphosphatemia. Typical soft tissue calcification was observed in 3 autopsied cows. Additionally to the arterial calcification, 2 cows had multiple mineralized foci in several veins. In the Paddock A where EC occurred, the pasture contained 7-12% N. rivularis. In the other 6 paddocks (Paddocks B-G) where EC had not occurred, the pasture had 0.2-3.5% N. rivularis. Cows grazing in Paddock A had ∼30% lower pregnancy rates than cows from Paddocks B-G. At the slaughterhouse, the carcasses of 45 cows from Paddock A weighed 17.6% (p < 0.01) less than 93 carcasses of cows from Paddocks B-G. Furthermore, the carcasses of cows from Paddock A were classified as low quality. Eight cows with EC signs from Paddock A and 10 cows without EC signs from Paddocks B-G were removed to a Lolium multiflorum pasture. After 120 days of grazing, the cows from Paddock A gained 45.2% less (p < 0.01) live weight than cows from Paddocks B-G. Poisoning with N. rivularis may cause significant economic losses in Uruguay due to low fertility rates and weight gain of affected cattle.

Poisoning of calves reared with cows treated with abamectin.

The aim of the present study was to describe an outbreak of poisoning by abamectin in calves less than four months of age whose mothers were treated with a pour-on product containing this ingredient. The diagnosis was based on the history, clinical signs, absence of macroscopic and histopathological findings (characteristic of this type of poisoning) and the detection of abamectin in tissues of the animals submitted to necropsy. Based on this report, the recommendation is the use with caution of pour-on formulations containing abamectin on cows having given birth less than four months earlier.

The prevalence of gross pathological damage in the livers of dairy cattle at processing plants in autumn in the North Island of New Zealand and an assessment of the gross liver pathology score as a method for estimating the prevalence of facial eczema.

AIM: To measure the prevalence of gross pathological damage in the livers of dairy cows at slaughter in the North Island of New Zealand in 2018 and 2019 and to determine, using Bayesian latent class analysis, the specificity and sensitivity of gross liver pathology score (GLS) as a method for detecting moderate to severe facial eczema (FE) at processing plants. METHOD: Meat inspectors at four processing plants located in the Northland, Waikato, Bay of Plenty and Taranaki regions of New Zealand graded all dairy cattle livers on particular days in April and May of 2018 and 2019 using a gross liver pathology score (GLS) from 0-5 (0 = no damage, 1= fatty liver, 2 = cholangitis and early cirrhosis, 3 = cirrhosis, 4 = extensive cirrhosis, 5 = regeneration). Forty livers from each grade were selected for histopathology. Sections from the apical margin of the right and the left lobes were scored using a histology biliary score (HBS; scored from 1-16) based on the classical histological lesions of FE focussing on changes that differentiate FE from fasciolosis. Mean HBS was collapsed into scores 2-6 (no and mild damage) and score 7-12 (moderate and severe) and GLS was collapsed into grades 0-2 (no or mild damage) and grades 3-5 (moderate, severe and chronic damage). A Bayesian latent class model was developed to estimate sensitivity and specificity of HBS and GLS. The diagnostic target was moderate or severe, gross and/or histological changes in the liver consistent with FE. RESULTS: A total of 2,899 dairy cow livers were graded at the four plants over the two study periods. There were 700/2,899 (24.1%) livers with at least some form of gross pathology damage (GLS≥1) and 130/2,899 (4.5%) livers with moderate, severe or chronic gross pathology damage (GLS≥3). The estimates (posterior median) for the sensitivity and specificity of GLS to liver damage were 0.844 (95% credible interval (CrI) = 0.757-0.905) and 0.932 (95% CrI = 0.866-0.973) respectively. Estimates for HBS were 0.834 (95% CrI = 0.765-0.892) and 0.778 (95% CrI = 0.707-0.854), respectively. CONCLUSION AND CLINICAL RELEVANCE: GLS is a useful means of estimating liver damage consistent with FE at slaughter. Increased use of liver scoring at slaughter could be useful for monitoring the likely impacts of FE at the country and regional levels.

Evaluation of Resistance to Fescue Toxicosis in Purebred Angus Cattle Utilizing Animal Performance and Cytokine Response.

Fescue toxicosis is a multifaceted syndrome common in cattle grazing endophyte-infected tall fescue; however, varying symptomatic responses potentially imply genetic tolerance to the syndrome. It was hypothesized that a subpopulation of animals within a herd would develop tolerance to ergot alkaloid toxicity. Therefore, the goals of this study were to develop selection criteria to identify tolerant and susceptible animals within a herd based on animal performance, and then examine responsive phenotypic and cytokine profiles to fescue toxicosis. Angus cows grazed endophyte-infected tall fescue at two locations for 13 weeks starting in mid-April 2016. Forage measurements were collected to evaluate ergot alkaloid exposure during the study. A post hoc analysis of animal performance was utilized to designate cattle into either tolerant or susceptible groups, and weekly physiological measurements and blood samples were collected to evaluate responses to chronic exposure to endophyte-infected tall fescue. Findings from this study support the proposed fescue toxicosis selection method formulated herein, could accurately distinguish between tolerant and susceptible animals based on the performance parameters in cattle chronically exposed to ergot alkaloids, and provides evidence to warrant additional analysis to examine the impact of ergot alkaloids on immune responsiveness in cattle experiencing fescue toxicosis.

Plant and Fungal Hepatotoxicities of Cattle in Australia, with a Focus on Minimally Understood Toxins.

Plant- and fungus-derived hepatotoxins are a major cause of disease and production losses in ruminants in Australia and around the world. Many are well studied and described in the literature; however, this is not the case for a number of hepatotoxicities with economic and animal welfare impacts, such as acute bovine liver disease (ABLD), brassica-associated liver disease (BALD) and Trema tomentosa, Argentipallium blandowskianum and Lythrum hyssopifolia toxicity. Additionally, significant overlap in the clinical presentation and pathology of these conditions can present a diagnostic challenge for veterinarians. This review summarizes the current and most recently published knowledge of common plant- and fungus-associated hepatotoxins affecting cattle in Australia, with a focus on the mechanisms of toxicity and distinguishing diagnostic features. Consolidation of the current understanding of hepatotoxic mechanisms in cattle provides insight into the potential mechanisms of lesser-known toxins, including cellular and subcellular targets and potential metabolic pathways. In the absence of specific etiological investigations, the study of epidemiological, clinical and pathological features of hepatotoxicity provides valuable insights into potential toxic mechanisms and is integral for the successful diagnosis and management of these conditions.

Ionophore Use and Toxicosis in Cattle.

Ionophores are a commonly used feed additive for animals and when used properly are safe. When feed mis-mixing occurs and an elevated dose of ionophore is given, a toxicosis can develop. Myocardial and skeletal muscles are the targets of a toxicosis. In many species there is a delay from the time of ingestion of a toxic dose in feed to when clinical signs occur. This makes it difficult to collect the feed in question that was at an elevated concentration. Cardiac troponins in serum can be used to make a diagnosis of an ionophore toxicosis.

Biofuels Co-Products Tolerance and Toxicology for Ruminants: An Update.

Corn co-products are a co-product of the dry and wet corn-milling ethanol manufacturing industry. The dry mill corn co-product is distiller's grains. Distillers grain can be further categorized into dry distillers grains (DDG), DDG with solubles, wet distillers grains with solubles (WDGS), modified WDGS, and corn syrup (solubles). Wet mill ethanol production produces 2 main feed stuffs: corn gluten (wet and dry) and heavy steep water.

Water Quality for Cattle: Metalloid and Metal Contamination of Water.

Water is the most important nutrient for rangeland livestock. However, competition with municipalities, industry, and other water users often results in grazing livestock being forced to use water supplies that are less than perfect. Surface water in western rangleands are often contaminated by mineral extraction, irrigation runoff and other human activities. Mineral contaminants in drinking water are additive with similar contaminants in feedstuffs. The goal of this article is to provide producers and veterinarians with the basic background to make informed decisions about whether a given water supply is "safe" for livestock.

Evaluating acute inflammation's effects on hepatic triglyceride content in experimentally induced hyperlipidemic dairy cows in late lactation.

Inflammation appears to be a predisposing factor and key component of hepatic steatosis in a variety of species. Objectives were to evaluate effects of inflammation [induced via intravenous lipopolysaccharide (LPS) infusion] on metabolism and liver lipid content in experimentally induced hyperlipidemic lactating cows. Cows (765 ± 32 kg of body weight; 273 ± 35 d in milk) were enrolled in 2 experimental periods (P); during P1 (5 d), baseline data were obtained. At the start of P2 (2 d), cows were assigned to 1 of 2 treatments: (1) intralipid plus control (IL-CON; 3 mL of saline; n = 5) or (2) intralipid plus LPS (IL-LPS; 0.375 µg of LPS/kg of body weight; n = 5). Directly following intravenous bolus (saline or LPS) administration, intralipid (20% fat emulsion) was intravenously infused continuously (200 mL/h) for 16 h to induce hyperlipidemia during which feed was removed. Blood samples were collected at -0.5, 0, 4, 8, 12, 16, 24, and 48 h relative to bolus administration, and liver biopsies were obtained on d 1 of P1 and at 16 and 48 h after the bolus. By experimental design (feed was removed during the first 16 h of d 1), dry matter intake decreased in both treatments on d 1 of P2, but the magnitude of reduction was greater in LPS cows. Dry matter intake of IL-LPS remained decreased on d 2 of P2, whereas IL-CON cows returned to baseline. Milk yield decreased in both treatments during P2, but the extent and duration was longer in LPS-infused cows. Administering LPS increased circulating LPS-binding protein (2-fold) at 8 h after bolus, after which it markedly decreased (84%) below baseline for the remainder of P2. Serum amyloid A concentrations progressively increased throughout P2 in IL-LPS cows (3-fold, relative to controls). Lipid infusion gradually increased nonesterified fatty acids and triglycerides in both treatments relative to baseline (3- and 2.5-fold, respectively). Interestingly, LPS infusion blunted the peak in nonesterified fatty acids, such that concentrations peaked (43%) higher in IL-CON compared with IL-LPS cows and heightened the increase in serum triglycerides (1.5-fold greater relative to controls). Liver fat content remained similar in IL-LPS relative to P1 at 16 h; however, hyperlipidemia alone (IL-CON) increased liver fat (36% relative to P1). No treatment differences in liver fat were observed at 48 h. In IL-LPS cows, circulating insulin increased markedly at 4 h after bolus (2-fold relative to IL-CON), and then gradually decreased during the 16 h of lipid infusion. Inducing inflammation with simultaneous hyperlipidemia altered the characteristic patterns of insulin and LPS-binding protein but did not cause fatty liver.

Use of aspirin to intentionally induce gastrointestinal tract barrier dysfunction in feedlot cattle.

Stress negatively affects the gastrointestinal tract (GIT) barrier function, resulting in compromised animal health. A deeper understanding of how diet and stress impacts the GIT barrier function in feedlot cattle is needed. Aspirin decreases mucus production and mucosal repair in the GIT and could be used as a model for GIT barrier dysfunction research. The objective of this study was to evaluate the effectiveness of aspirin to induce GIT barrier dysfunction in beef cattle. In experiment 1, sixteen crossbred heifers (425.0 ± 8.6 kg) were allotted to 0, 50, 100, or 200 mg/kg body weight (BW) aspirin doses based on BW. Experiment 1 consisted of two periods separated by 4 wk where four heifers per treatment received the same aspirin dose during each period. Heifers were fed a 49.4% corn silage and 50.6% concentrate diet. The 200 mg/kg BW aspirin treatment was dosed as a 100 mg/kg BW aspirin oral bolus 36 and 24 h prior to Cr-ethylenediaminetetraacetic acid (EDTA) dosing (1 liter; 180 mM). The 50 and 100 mg/kg BW aspirin treatments were dosed as an oral bolus 24 h prior to Cr-EDTA dosing. Urine was collected every 3 h for 48 h and analyzed for Cr. Serum was collected at 0 and 48 h and analyzed for lipopolysaccharide-binding protein (LBP), interleukin-6, serum amyloid A (SAA), haptoglobin, and aspartate aminotransferase. In experiment 2, sixteen crossbred steers (576.0 ± 14.2 kg) fed a similar diet were allotted by BW to the 0 and 200 mg/kg BW aspirin treatments (eight steers/treatment) and were slaughtered 24 h after the last dose. Jejunal tissues were collected, and claudin (CLDN) 1, 2, and 3, occludin, and zonula occludens tight junction messenger ribonucleic acid (mRNA) expression was determined. Data were analyzed using the MIXED procedure of SAS. Urinary Cr excretion increased linearly at hours 3, 6, 9, and 12 (P ≤ 0.04) as aspirin dose increased from 0 to 200 mg/kg. Aspirin linearly increased Cr absorption (P = 0.02) and elimination (P = 0.04) rates and linearly decreased mean retention time of Cr (P = 0.02). Aspirin increased SAA (P = 0.04) and tended to increase LBP (P = 0.09) in serum but did not affect any other serum inflammatory marker (P ≥ 0.19). Aspirin tended to increase jejunal CLDN-1 mRNA expression (P = 0.10) but did not affect the mRNA expression of other genes regulating tight junction function (P ≥ 0.20). Results from this study indicate that aspirin disrupts the GIT barrier function in beef cattle and has a potential as a model in GIT permeability research.

Short communication: Hypernatremia in diarrheic calves associated with oral electrolyte administration in water and milk replacer in absence of access to water.

A major goal in treatment of calves with diarrhea is to restore hydration and to correct metabolic acidosis. This can be achieved by the administration of oral electrolyte solutions (OES). However, the composition of OES products and the administration protocols in practice vary widely, which can potentially compromise the efficacy and safety of these treatments. In particular, administration of OES in milk replacer (MR) and the absence of water supply in young calves are not unusual and these conditions could compromise calf health. In this light, the objective of this study was to evaluate the efficacy and safety of OES administered in MR and in water without access to water. Forty-five male Holstein calves (16.6 ± 1.6 d of age and 45.4 ± 2.2 kg at arrival) were purchased from a collection center located in the Netherlands. After arrival, calves went through an adaptation period of 4 d. Calves that developed diarrhea within 6 d after the end of the adaptation period were enrolled in the study, and the remaining calves were sold after being weaned. Upon morning detection of abnormal fecal scores (d 1 starting point), calves were blocked based on initial BW. Within each block, calves were randomly assigned to 1 of 2 treatments, including a control consisting of a small dose of whey (CON; n = 12) and an OES treatment (OES; n = 14). Treatments were blinded to the farm staff by randomly assigning a letter to each treatment. Treatments were simultaneously administered for 4 d in MR (2.5 L at 0800 and 1730 h) and in water (3 L at 1300 and 2200 h). Calves had no supplemental access to plain water. Blood samples were taken at 0600 h for 4 d, and fecal scores (0 = normal; 1 = watery feces) were assessed daily at 0900 h for 15 consecutive days. Additionally, skin turgor and degree of enophthalmos were assessed at 1000 h from d 1 to 4 using a 3-level scoring system. Calves fed OES had a higher prevalence of diarrhea on d 3, 4, and 5 as well as higher prevalence of delayed skin turgor and increased degree of enophthalmos over the 4 monitoring days. Diarrhea duration was longer in calves receiving OES than in calves receiving CON (4.2 d vs. 2.1 d, respectively). The OES treatment resulted in hypernatremia (serum Na+ >145 mmol/L) within 48 h after the first OES administration. Hypernatremia was linked with higher serum Cl- and urea concentrations and thus higher serum osmolarity in OES calves compared with CON calves. Administered under these conditions, OES resulted in various degrees of hypernatremia and a delayed recovery from diarrhea, thus defeating the purpose of OES administration.