Thiamine ameliorates inflammation of the ruminal epithelium of Saanen goats suffering from subacute ruminal acidosis.

This study aimed to examine the role of thiamine in the local inflammation of ruminal epithelium caused by high-concentrate diets. Eighteen mid-lactating (148 ± 3 d in milk; milk yield = 0.71 ± 0.0300 kg/d) Saanen goats (body weight = 36.5 ± 1.99 kg; body condition score = 2.73 ± 0.16, where 0 = emaciated and 5 = obese) in parity 1 or 2 were selected. The goats were randomly divided into 3 groups (n = 6/group): (1) control diet (concentrate:forage 30:70), (2) high-concentrate diet (HC; concentrate:forage 70:30), and (3) high-concentrate diet with 200 mg of thiamine/kg of dry matter intake (THC; concentrate:forage 70:30). Goats remained on experimental diets for 8 wk. On the last day of 8 wk, ruminal and blood samples were collected to determine ruminal parameters, endotoxin lipopolysaccharide, and blood inflammatory cytokines. Goats were slaughtered to collect ruminal tissue to determine gene and protein expression of toll-like receptor 4 (TLR4) signaling pathways. Thiamine supplementation increased ruminal pH (6.03 vs. 5.42) compared with the HC group. Propionate (21.08 vs. 31.61 mM), butyrate (12.08 vs. 19.39 mM), lactate (0.52 vs. 0.71 mM), and free lipopolysaccharide (42.16 vs. 55.87 × 103 endotoxin units/mL) concentrations in ruminal fluid were lower in THC goats compared with HC goats. Similar to plasma interleukin 1ß (IL-1ß) concentration (209.31 vs. 257.23 pg/mL), blood CD8+ percentage (27.57 vs. 34.07%) also decreased in response to thiamine. Compared with HC goats, THC goats had lower ruminal epithelium activity of the enzymes myeloperoxidase and matrix metalloproteinase (MMP) 2 and 9. In contrast to HC, THC had downregulated mRNA expression of nuclear factor-κB (NFKB), TLR4, IL1B, MMP2, and MMP9 in ruminal epithelium. Thiamine supplementation led to lower relative protein expression of IL-1ß, NF-κB unit p65, and phosphorylated NF-κB unit p65 in ruminal epithelium. Taken together, these results suggest that thiamine supplementation mitigates HC-induced local inflammation and ruminal epithelial disruption.

Rumenolith formation in a Bapedi ram.

During a routine flock visit, a farmer observed that one of the eight tooth Bapedi rams had been losing body condition despite being separated from the flock and fed supplementary feed. The ram's body condition score was assessed as 2 out of 5 (one point less than the average of the rest of the rams) and the teeth appeared normal with no excessive wear. The rumen was assessed by auscultation, palpation and ballottement where a foreign body (approximately 20 cm × 5 cm - 10 cm) was clearly palpated and ballotted. A rumenotomy was performed and a large mass of tightly compacted foreign matter and plant material was removed. The mass consisted of synthetic fibre, plant material and calcium phosphate (50.5%). It appeared to have formed as the result of the ingestion of a synthetic fibre which formed the nidus of a concretion. This was probably the result of deficient nutrition, with the rams eating the synthetic fibre in an attempt to increase feed intake. The ram recovered uneventfully after the rumenotomy was performed and supplementary feeding.

Aspectos clínicos da indução experimental de acidose láctica ruminal em zebuínos e taurinos / Clinical evaluation of zebuine and taurine cattle with acute rumen lactic acidosis

Utilizaram-se cinco garrotes Jersey (J) (Bos taurus) e cinco Gir (G) (Bos indicus) para comparar a susceptibilidade racial, por meio do quadro clínico, à acidose láctica ruminal aguda (ALRA), induzida experimentalmente. A ALRA foi caracterizada por taquicardia, redução dos movimentos ruminais, diarreia, desidratação e depressão no estado geral. Embora os bovinos G apresentassem maior taquicardia e uma tendência a uma desidratação mais severa, assim como estase ruminal, foram os J que manifestaram maior depressão no estado geral, requerendo um tratamento mais intenso para a recuperação. A normalização do apetite após o tratamento da ALRA foi mais demorada nos bovinos J. O conjunto de resultados indicou que os bovinos J são mais susceptíveis a desenvolverem quadros mais graves de ALRA, que os G. Quanto maior o déficit do volume plasmático, mais intensa a taquicardia (r = 0,67); não ocorreu influência do pH sanguíneo sobre a frequência cardíaca (r = - 0,25).

To compare the clinical signs and the susceptibility to acute rumen lactic acidosis (ARLA), experimentally induced, five Jersey (J) (Bos taurus) and five Gir (G) (Bos indicus) steers were used. The ARLA caused in all animals tachycardia, decreased rumen movement, diarrhoea, and dehydration; Although G steers presented higher tachycardia and tendency to a more severe dehydration, the J steers exhibited a pronounced depression in the general state, requiring an intense treatment to recover. J steers needed more time to recover the normal appetite. Thus, regarding clinical picture, was observed that J steers are more susceptible to ARLA than G. Positive correlation was found between plasma volume deficit and tachycardia (r = 0.67); blood pH did not influence heart rate (r= - 0.25).

Clinical findings and treatment in 63 cows with haemorrhagic bowel syndrome.

The clinical, haematological and biochemical findings, treatment and outcome of 63 cows with haemorrhagic bowel syndrome are described. The general condition and demeanor were moderately to severely abnormal in all the cows. Signs of colic occurred in 27 cows, decreased rectal temperature in 46 and tachycardia in 44. With the exception of one cow, intestinal motility was decreased or absent. Transrectal palpation revealed dilatation of the rumen in 47 cows and dilatation of the small intestine in 18. Faecal output was markedly reduced or absent, and the faeces were dark brown to black and contained blood. Nine cows were euthanized immediately after physical examination. Conservative medical therapy was instituted in two cows; however, both were euthanized a few days later because of deterioration in condition. Exploratory right flank laparotomy was carried out in 52 cows. Of these, 22 were euthanized intraoperatively because of severe lesions. In 27 cows, intestinal massage to reduce the size of blood clots was carried out; 11 were euthanized several days postoperatively because of deterioration in condition. In three other cows, intestinal resection was carried out and all survived. Of the 63 cows, 19 (30.2%) survived and were healthy at the time of discharge from the clinic.

Rumen distension and contraction influence feed preference by sheep.

Distension of the rumen limits feed intake by livestock. Ruminal dysfunctions due to bloat, which causes distension by accumulation of excessive gas within the rumen, also reduce feeding. We hypothesized that excessive levels of rumen distension cause feed aversions and that preference increases for feeds eaten in association with recovery from bloat. To test these hypotheses, we determined whether 12 commercial crossbred lambs (average initial BW of 43 +/- 2 kg) could associate ingestion of specific feeds with the consequences of increased intraruminal pressure and its subsidence. Six of the lambs were fitted with rumen cannulas and offered ground alfalfa for 30 min after a rubber balloon was inserted into the rumen of each animal and distended with air to volumes of 1.8, 2.5, or 4.5 L. Subsequently, balloons were deflated and alfalfa was offered again for a second period of 30 min. Feed intake was not affected when the balloon was not distended (P = 0.45 to 0.93), but distension reduced feed intake (P < 0.001) in direct proportion to the magnitude of distension at all 3 volumes (R(2) = 0.70). Relief from distension promoted a compensatory increase in feed intake (P = 0.006). During conditioning to determine if lambs acquired a preference for a feed associated with recovery from distension, fistulated lambs were offered novel feeds: wheat bran (group 1; n = 3) and beet pulp (group 2; n = 3), and the balloon was distended for 30 min. Feeds were then switched and the balloons were deflated (recovery). Control lambs (n = 6) received the same feeding protocol without the balloons. Lambs formed strong aversions to feeds associated with distension and preferred feeds associated with recovery (P = 0.001 to P = 0.10). No preferences or avoidances were observed in control lambs conditioned without rumen distension (P = 0.17 to P = 0.87). Thus, rumen distension and recovery from distension induced feed aversions and preferences, respectively, which may be critical in learning avoidance of bloat-inducing plants and preferences for plants and supplements that relieve the incidence of bloat.

Impact of Bacillus thuringiensis toxin Cry1Ab on rumen epithelial cells (REC) - a new in vitro model for safety assessment of recombinant food compounds.

The growing use of genetically modified crops necessitates viable screening methods for safety evaluation of recombinant feed, particularly for ruminants. A new sheep rumen epithelial cell culture is introduced as an in vitro cell system for safety evaluation especially focussing on feed and food compounds. We used lactate dehydrogenase (LDH) release, WST-1 conversion, ATP content and caspase 3/7 activity to evaluate cytotoxicity of Cry1Ab, one of the newly expressed Bt-proteins in transgene maize. The results were compared to the effects of valinomycin, a potassium ionophore known to induce cytotoxic effects on a wide range of cells. Whereas no toxicity of Cry1Ab was observed in short as well as in long term experiments, even at non-physiological high concentrations, exposure to valinomycin induced apoptosis and a significant response of all viability parameters after a number of hours. The ATP content and the WST-1 conversion reflecting the energy metabolism of the cells appear to be more sensitive indicators of valinomycin toxicity than the LDH release, a parameter which reflects the membrane integrity. This study presents an in vitro model system, that may be useful as a supplementary tool in toxicity screening before testing substances on animals in vivo.

Feeding high proportions of barley grain stimulates an inflammatory response in dairy cows.

The objective of this study was to evaluate effects of feeding increasing proportions of barley grain on acute phase response in lactating dairy cows. Eight cannulated primiparous (60 to 140 d in milk) Holstein dairy cows were assigned to 4 diets in a 4 x 4 Latin square experimental design. The experimental period lasted for 21 d, with 11 d of adaptation and 10 d of measurements. Cows were fed the following diets: 1) no barley grain in the diet, 2) 15% barley grain, 3) 30% barley grain, and 4) 45% barley grain, as well as barley and alfalfa silage and alfalfa hay at 85, 70, 55, and 40% [dry matter (DM) basis]. All cows were supplemented with a 15% concentrate mix. Blood and rumen fluid samples were collected on d 1, 3, 5, 7, and 10 of the measurement period, and pH and endotoxin content were measured in rumen samples. Concentrations of serum amyloid A, lipopolysaccharide-binding protein, haptoglobin, and C-reactive protein in plasma were measured by ELISA. Feeding high proportions of barley grain at 0, 15, 30, and 45% of DM was associated with lower feed intake (32.6, 32.9, 27.34, and 25.18 kg/d +/- 1.30, respectively), lower ruminal pH (6.8, 6.7, 6.7, and 6.5 +/- 0.03, respectively), and higher DM intake (13.33, 15.28, 14.68, and 16.04 +/- 0.63 kg/d, respectively) and milk production (27.2, 28.2, 29.0, and 31.0 +/- 1.2 kg/d, respectively). Ruminal endotoxin increased in cows receiving 30 and 45% barley grain (5,021, and 8,870 +/- 393 ng/mL, respectively) compared with those fed no grain or 15% barley grain (654 and 790 +/- 393 ng/mL, respectively). Plasma concentrations of serum amyloid A, lipopolysaccharide-binding protein, and C-reactive protein increased in cows given higher (30 and 45%) proportions of grain. Plasma haptoglobin was not affected by treatments. In conclusion, feeding dairy cows high proportions (30 and 45% DM basis) of barley grain was associated with lower feed intake and rumen pH, increased endotoxin in the rumen fluid, and stimulation of an inflammatory response.

Intoxication of sheep with quebracho tannin extract.

This experiment was carried out to study the toxicity of quebracho tannin extract (containing 760 g of condensed tannins [CTs] per kg), with the aim of validating its use as a feed additive for improving the digestive utilization of protein-rich feeds. Four groups (Q(0), Q(1), Q(2) and Q(3)) of four sheep were dosed intra-ruminally once daily, for up to 21 days with, respectively, 0, 0.5, 1.5 or 3.0 g quebracho tannin extract/kg live-weight (LW). Feed intake, live-weight changes, plasma biochemistry, indicators of hepatic detoxification function, gross lesions and histopathology were examined. Animals in groups Q(0), Q(1) and Q(2) consumed all the offered feed. In contrast, feed intake was practically nil after 6 days of quebracho dosing in group Q(3), this being associated with a loss of 4.7+/-1.30 kg LW in 10 days (P<0.05). Sheep from groups Q(0), Q(1) and Q(2) remained healthy throughout the experiment. Ewes from group Q(3) became weak and depressed on day 5 and after 8 days of dosing remained recumbent. They were humanely killed after 10 days to avoid suffering. In general, neither gross lesions nor microscopical changes were observed in animals from groups Q(0), Q(1) and Q(2). However, Q(3) sheep showed striking lesions in the digestive tract (well-demarcated ulcers filled with necrotic material in the mucosa of the rumen and reticulum, distension of abomasum and small intestine, and dense mucous material in the caecum), and changes in plasma biochemistry. Cytochrome P-450 and glutathione concentrations were significantly reduced in Q(3) sheep (P<0.05). It is concluded that quebracho tannin extract is not toxic for ruminants, except in concentrations too high to be encountered under practical conditions.

The influence of different fibrous supplements in the diet on ruminal histology and histometry in veal calves.

The aim of this study was to determine whether the administration of four different solid feeds would influence selected morphological and morpho-functional aspects of the rumen mucosa in veal calves. The fibrous supplementation of the liquid diet of veal calves has been provided by recent EU formulation (EC Council Directive 91/629/1991; EC Council Directive 97/2/1997). Twenty-five Holstein calves were assigned to either exclusively liquid diet (milk replacer, control), or pelleted feed, corn silage, extruded feed, dried corn silage. The morpho-functional effects of the fibre-containing diets were examined evaluating histological and histometrical characteristics of ruminal mucosa after the slaughter of calves. There were slight to severe histological abnormalities in the rumens of all animals examined. The severe histological abnormalities were present in calves given pelleted feed, corn silage, and extruded feed. Dried corn silage caused less ruminal damage. We found that the length and epithelial thickness of ruminal papillae were higher in control veal calves than in dietary fibre-supplemented animals. The results of the present study, even if partially, support the EU prescription in the use of fibre diets in veal calves as integration of the traditional milk replacer diet.

Effect of pretreatment with selenium-vitamin E on monensin toxicosis in cattle.

Ten female beef calves weighing approximately 180 kg each were allotted to 2 groups of 5 each before they were given (orally) monensin (50 mg/kg of body weight). In group A, the calves were given (IM) a commercial selenium-vitamin E (Se-E) preparation (0.25 mg of Se and 17 IU of alpha-tocopherol/kg of body weight) at 72 and 24 hours before monensin was given. The calves in group B were injected at the 2 times with isotonic saline solution. Clinical signs of monensin toxicosis, including lethargy and recumbency, appeared on day 2 in the calves given the Se-E pretreatment, compared with the onset on day 1 in the saline solution-pretreated calves. All calves in the 2 groups died, but mean survival time was longer in group A (4.4 vs 2.2 days). Lesions of monensin toxicosis were myocardial necrosis, skeletal myonecrosis, pulmonary congestion, and rumenitis. The frequency and severity of the lesions were similar for both groups of calves. The results of the present study indicate that Se-E pretreatment modifies the development of monensin toxicosis in cattle.

Clinical, clinicopathologic, and pathologic alterations in acute monensin toxicosis in cattle.

Twenty beef calves weighing approximately 180 kg were allotted to 3 groups. In group A, 6 calves were given 25 mg of mycelial monensin/kg of body weight orally and were evaluated at 1, 2, and 4 days for clinical, ECG, clinicopathologic, and pathologic alterations. In group B, 7 calves were given a single dose of monensin (40 mg/kg) and 5 were given a 2nd 40 mg/kg dose on day 7; calves were evaluated at days 1, 2, 4, 7, 8, 9, and 11. In group C, 2 calves served as controls. Monensin-treated calves developed anorexia, diarrhea, and lethargy after day 1. One group B calf died on day 7 with lesions of congestive heart failure. Electrocardiographic abnormalities were not observed in group A calves; in group B, prolongation of Q-T and QRS intervals occurred from days 2 to 11 and first degree heart block was seen from days 7 to 11. Clinicopathologic alterations included: increased serum activities of aspartate aminotransferase and creatine kinase in group B calves after day 2; decreased serum K+, Na+, and Ca2+ concentrations in both groups, and postdosing occurrence of leukocytosis. Calves were euthanatized sequentially and the lesions of monensin toxicosis were present in the heart, skeletal muscles, and rumen in groups A and B. Disseminated pale yellowish-brown areas of necrosis were present in the ventricular myocardium of 6 of 12 group B calves. Gross lesions were not present in the skeletal muscles or rumen. Microscopically, the myocardial and skeletal muscular lesions were characterized by sarcoplasmic vacuolation from mitochondrial swelling and lipid accumulation in calves killed after day 1 in groups A and B, and by myocardial necrosis with contraction bands, but without calcification, in group B calves killed by day 4. Acute rumenitis was present in groups A and B calves. Myotoxic effects of monensin may be related to its action as an ionophore producing altered intracellular ion concentrations and initiating degeneration and necrosis in striated muscle fibers.

Gastric pathology and feeding deficits induced by hypothalamic damage in rats: effects of lesion type, size, and placement.

Three doses each of cathodal or anodal direct current were delivered to coagulate lateral hypothalamic tissue bilaterally in rats. Increases in hypothalamic tissue damage were associated with more instances of aphagia, greater amounts of glandular, but not rumenal, gastric pathology, and greater weight loss. Both anodal and cathodal lesions produced aphagia and similar amounts of gastric pathology, but anodal lesions also appeared to facilitate weight loss independently of the tissue damage. Extensive chromatolysis surrounding anodal lesion cavities may be importantly related to the postoperative effects. In additional experiments, anodal electrolytic lesions or cortical suction ablations were used to vary the location of neural damage. Fedding deficits and gastric pathology resulted from the destruction of several brain areas. In particular, eating of dry food in the presence of high gastric pathology was observed in rats with lesions ventral and medial to an area in the dorsolateral hypothalamus that was associated with aphagia. When aphagia was accompained by severe gastric pathology, the brain lesions typically encroached extensively on more ventromedial areas. Moreover, aphagia sometimes was observed with only negligible gastric pathology. It is suggested that gastric pathology is not primary to the expression of the aphagia that follows lateral hypothalamic damage.