Iranian Journal of Veterinary Research
Volume:8 Issue: 2, Spring 2007

The objective of this study was to evaluate several drug combinations for intraperitoneal anaesthesia in laboratory rats. Following dose determination of anaesthetics in a pilot study, 45 healthy adult male rats were randomly assigned in 9 treatment groups and received propofol (alone or in combination with xylazine, midazolam, or ketamine) or ketamine (in combination with xylazine, midazolam, acepromazine, acepromazine-xylazine, or midazolam-xylazine). Heart and respiratory rate, induction and total sleep times, duration of surgical anaesthesia and walking time were measured. Complete immobility and loss of righting reflex were observed within 12 min in all groups. Induction of anaesthesia was significantly longer following XP compared to other groups. Surgical anaesthesia was induced in all rats receiving XK, AXK and MXK, while propofol alone, MK and KP were associated with surgical anaesthesia in 2, 3 and 4 rats, respectively. Other combinations did not produce surgical anaesthesia. Duration of surgical anaesthesia was longest with MXK and shortest with MK. In conclusion, the most effective drug combinations, which result in longer duration of surgical anaesthesia, were AXK and MXK. Although the degree of analgesia produced by IP propofol is sufficient for restraint and non-painful procedures, the combination of ketamine-propofol can produce surgical anaesthesia in the rat.

The ramifications of the portal vein in the liver of horses were studied by using corrosion casting and gross dissection. The portal vein in the horse supplies the hepatic lobes by six major branches. The right lobe is supplied by three main branches, namely the dorsal diaphragmatic, the right caudodorsal and the right intermediate branches. The left branch supplies the left lateral and medial lobes and parts of the quadrate lobe adjacent to the left medial lobe. The caudate branch supplies caudate process of the caudate lobe. The right common trunk supplies also a part of right lobe and quadrate lobe. Therefore, the pattern of blood distribution in portal vein of horse differs from that of other species.

Despite a shortage of animal feed in Iran, cereal stubble is often underutilized due to agro-economic reasons. On the other hand, lambs fed with a conventional fattening ration deposit a considerable amount of fat; therefore, this experiment was conducted aimed at better utilization of cereal stubble and reducing the fat content of lamb carcasses. Fat-tailed Mehraban and Ghezel ram lambs were put on four feeding systems (FS) for 100 days. Animals in one group (FS1) were lot-fed with a conventional fattening ration (4% of the mean body weight) consisting of 50% ground barley and 50% chopped alfalfa hay. FS2, FS3 and FS4 animals grazed stubbles, and in the evening, received 2% of their body weights either ground barley (FS2), a mixture (50:50 DM basis) of ground barley and alfalfa hay (FS3), or ground alfalfa hay (FS4). Daily gain, slaughter weight, and tail weight were greatest (P<0.05) for FS1, lowest for FS4, and intermediate for FS2 and FS3. Stubble-fed lambs had lower subcutaneous fat depth and cavity fat. The sum weight of lean in primal cuts was lower in FS4 as compared with other groups, but the lean weight as a percentage of carcass weight was lowest in SF1. Similar pattern was found for the dissected fat from the primal cuts. The weight of soft tissues was highest in SF1 and lowest in SF4, but its percentage in carcass showed a reverse pattern. Stubble feeding with some supplementary feed resulted in less fat deposition in fat-tailed lambs as compared with the conventional fattening ration, and was more economical in terms of unit live weight gain. Due to the feed shortage in Iran, stubble grazing should be encouraged in lieu of the current practice of burning the residues on the farm.

No report has been published on the economical losses associated with errors in oestrus detection in cows under Iranian intensive dairy management. The following study was carried out to determine the accuracy of oestrus detection by farmers using artificial insemination in Shiraz dairy farms. Milk samples were collected from 179 Holstein milking cows at the time of artificial insemination. Milk progesterone concentration was determined using a commercial radio-immunoassay kit. It was assumed that a milk progesterone concentration greater than or equal to 3 ng/ml indicated the presence of active luteal tissue and that all animals in oestrus had a concentration less than 1 ng/ml. Results of the present study showed that error in oestrus detection was higher in dairy herds with more than 85 milking cows compared to that of the smaller size herds (14.4 vs 7.3%; χ2 = 2.59; P = 0.1). Five out of 11 herds (45%) had an oestrus detection error higher than 10 percent while in the remaining six herds the oestrus detection error varied from 0 to 7.1%. Based on the assumptions and calculations made in the present study, the net cost of one day delay in conception for a cow producing 25 litres milk in peak lactation was calculated at 40591.98 Rials (4.51 $US) when conception is delayed from 85 to 100 days post-calving, increasing to 60120.89 Rials (6.68 $US) per day if conception occurred at 146 to 175 days post-calving.

Tetracycline may be used to treat several types of bacterial diseases in ruminants. In addition, tetracycline is added to food to promote the growth. There are few reports on the pharmacokinetics of tetracycline in sheep. Therefore, the objective of this study was to examine the pharmacokinetic characteristics of the drug in sheep. Ten apparently healthy mixed-breed sheep were administered 20 mg/kg tetracycline orally and intravenously with a time interval of two weeks. Blood samples were collected before and at various time intervals after the administration of the drug. Sera were separated, kept at -20°C, and analysed using fluorescence spectrophotometry. The volume of distribution (Vd), elimination rate constant (Kel), half-life (t1/2), and clearance (ClB) of tetracycline after intravenous injection were determined to be 0.21 L/kg, 0.21/hr, 3.3 hr, and 0.73 ml/kg/min, respectively. When the drug was given orally, these parameters were found to be 0.37 L/kg, 0.12/hr, 5.8 hr, and 0.73 ml/kg/min, respectively. Moreover, the bioavailability of tetracycline after oral administration was around 55%.

Three-hundred and twenty 7-day-old Ross 308-strain broiler chickens were fed diets containing 0 or 125 ppb aflatoxin B1 (AFB1) from 7 to 28 days of age. Sodium bentonite (0.5%), yeast (Saccharomyces cervisiae) 0.2%, hydrated sodium calcium aluminosilicate (HSCAS) (0.5%), ammonia (0.5%), formycine (0.1%), and toxiban (0.1%) were added to the basal diet, as fed basis to determine the effects of these additives against aflatoxicosis. Diet free from aflatoxin, and diet containing aflatoxin (negative control group) were considered as comparison groups. Broiler chickens were divided into 32 groups of 10 with similar mean ± SD weight of 90 ± 0.64 g. Each experimental diet was replicated 4 times during 21 days. Body weight gain, daily weight gain, feed conversion ratio, daily and weekly feed intake, relative weight of organs (liver, intestines, heart, proventriculus and gizzard) and total serum protein were recorded. Relative weight of organs in chickens fed with diet containing AFB1 alone were significantly greater (P<0.01) than that of those fed with other diets. Their body weight gain, daily weight gain, total serum protein concentration, however, were significantly lesser (P<0.01) compared with those fed with other diets. Experimental diets decreased the relative weight of organs in chickens fed with diets containing aflatoxin along with any of the experimental diets as compared with the negative control group. The feed conversion ratios were higher in chickens fed with diets containing aflatoxin. On the other hand, chickens receiving various additives in their diets showed an increase in body weight gains, serum total protein concentration and an improvement in the feed conversion ratio when compared with the negative control group (P<0.01). Generally, addition of the above compounds made an improvement against negative effects of AFB1 in broiler chickens. Formycine was recognized to be the best additive in this respect.

During spring, summer and winter seasons, Sistani donor cows, with normal reproductive status, were superovulated and embryos were recovered non-surgically on day 7. Grade A blastocyst embryos were either transferred fresh (spring) or frozen (summer and winter). Recovered embryos during summer and winter were exposed to glycerol and frozen using conventional method. During spring season, recipient females (n = 70) were synchronized using two consecutive injections of prostaglandin F2α analogue, 14 days apart. On day 7 after the ensuing cycle, the females were assigned into three groups to receive single embryo, either fresh (n = 14; control; recovered embryos in spring) or frozen blastocyst recovered and frozen in summer (n = 27) or winter (n = 29). Pregnancies were diagnosed by ultrasound examination, 30 days after non-surgical embryo transfer. Pregnancy rates following transfer of fresh embryos (64.3%) were higher than those that received frozen-thawed embryos (17.86%; P<0.05). There was not any significant difference between pregnancy rates of recipients receiving embryos frozen in summer (18.5%) or winter (17.2%; P>0.05).

The influence of hypo- and hyper-thyroidism on spermatogenesis was studied in 60-day-old adult male Wistar rats. To confirm hypo- and hyper-thyroidism, the concentration of plasma thyroid hormones were assayed by radioimmunoassay. The hypothyroid state, induced by administration of 25 mg/kg/day methimazole for 5 successive days, resulted in significant decrease in the number of Sertoli cells, sperm count, Leydig cells and the diameter of seminiferous tubules. The hyperthyroid state, induced by administration of 1 mg/kg/day L-thyroxine for 10 successive days, increased the number of Sertoli cells, sperm count, Leydig cells and the diameter of seminiferous tubules. Serum levels of FSH and LH and testosterone were also evaluated. Hypo- and hyper-thyroidism had no effects on the concentrations of FSH and LH, while the concentration of testosterone was significantly increased in hyperthyroid state; it decreased in hypothyroid state in comparison with the control euthyroid rats. In conclusion, our data indicated that hypo- and hyper-thyroidism affect spermatogenesis through their effects on germinal, interstitial and Sertoli cells but not through the pituitary-gonadal axis.

This study was carried out to control Johne’s disease (JD) without interfering with tuberculosis (TB) control programme. A dairy herd (n>1500 heads) was used over a period of 6 years, from 1994 to 1999 for this investigation. The herd had a history of heavy infection with Mycobacterium avium paratuberculosis (MAP) with culling rates of 1.5 and 5%, in 1991 and 1995, respectively. The mean annual losses due to the reduction in milk yield, pregnancy rate and carcass weight was about $32000. In addition, the farm has had positive tuberculin test. During this study, 2070 calves within 31 days of age, were inoculated once subcutaneously, with MERIAL JD attenuated vaccine, in the middle of brisket region. The vaccine protected the herd against JD effectively, so that from 1995 up to the end of 1999, the means of JD culling among 2-year-old vaccinated and unvaccinated cattle were 0.52 and 19.4%, respectively. This vaccination had no side-effects on TB control programme that was conducted by the comparative tuberculin test. In the site of inoculation, fibrocaseous inflammation, while increasing in size, was developed. During 2 years, in the majority of animals, this reaction disappeared; only in less than 1.5% of instances the lesion became tumoral and permanent. These animals had no clinical abnormality. While inoculating the vaccine, the insertion of vaccine germ contaminated needles in fingers of vaccinators usually caused temporary, hard and painful inflammation. In one occasion, a progressive granuloma caused by vaccine germ was diagnosed histopathologically and treated with suitable antibiotics.

Ticks are important ectoparasites which are a considerable threat to human beings and to animals all over the world. Enormous economic losses annually occur in livestock production around the world as a result of their existance. One of the ways to control ticks and tick-borne diseases is to introduce resistance to these ectoparasites through immunization. For identification of the putative protective antigens, screening of large number of parasite antigens and their fractions are necessary. In this study, midguts of fed adult female Hyalomma anatolicum anatolicum were used to prepare antigen and to identify the midgut profile. Polypeptide profile was analysed by SDS-PAGE with 12.5% concentration under denaturated conditions and discontinuous buffer system. Humoral immunity and antigenic pattern were evaluated by Western blot. A total of 4 fractions were observed in the polypeptide profile. The molecular weight of the fractions were 97, 84, 66 and 55 kDa. The band with molecular weight of 66 kDa was dominant. Positive reaction with 84, 66 and 55 kDa bands were observed in immuno-blot of the midgut antigens.

The objective of this study was to determine the chronology of changes in blood pressure in renal hypertension induced by solid plexiglass clips in rats. Saw blades with the thickness of 0.21-0.22 mm were used to make clips sized 4 × 2 × 2 mm from a piece of 2-mm thick plexiglass. Rats were subjected to sham-operation or left renal arterial clipping, and 1, 2, 3 and 4 weeks later blood pressure, and heart and kidneys weights were determined. Relative to those of sham-operated rats, mean blood pressure of left renal artery-clipped rats were significantly higher at week 1 through 4 after clipping. Left renal artery clipping was also associated with significant increases in heart and right kidney weights and significant decrease in left kidney weight. The findings suggest that clipping of left renal artery using solid plexiglass clips resulted in changes in blood pressure, heart and left and right kidneys weights similar to reported changes in hypertension induced by silver clips.

Three adult pigeons (Columbia livia) belonging to a pigeon farm in Mashhad area were submitted to Poultry Clinic of School of Veterinary Medicine for post-mortem inspection. The farm had 150 adult pigeons and a number of them suffered from a chronic disease with body weight loss, diarrhoea and weakness. At necropsy, slight to extreme enlargement with distortion were observed in gizzards of all carcases. There was a large number of nematodes in or beneath the lining of the affected gizzards. The worms were removed from the lining of the rostral parts of the gizzards and cleared in lactophenol. Also, tissue blocks from various parts of the gizzards were processed by conventional methods for preparation of paraffin wax sections. Based on parasitological and pathological findings the Hadjelia truncata infestation was identified for the first time from Iran and this species is a pathogenic agent for pigeons.

A three-month-old male native puppy with lameness, metaphyseal swelling, pain, depression, inappetence and variable pyrexia was diagnosed as having hypertrophic osteodystrophy (HOD) based on radiologic examination. The hemogram and biochemical profiles were within normal limits. Radiologic examination revealed a radiolucent zone in the metaphyses and a radiopaque band near the physes of the appendicular long bones. Periosteal new bone formation was seen around of the distal metaphyses of the radii, ulnae and tibiae. Currently, there is no specific treatment for HOD. The condition of puppy was improved following restriction of activity, confinement to small well-padded area, administration of high-quality diet and anti-inflammatory drug (aspirin, 10 mg/kg PO q12h for two weeks). To the best of our knowledge, it is the first report of HOD in mongrel puppies in Iran.

An adult (two years old) Iranian cross-breed ram with alopecia, rough hair coats, thick and wrinkled skin, especially on the face, brisket, scrotum, tail and legs, presented with severe pruritus, poor condition and generalized unthriftiness. The animal was referred to the Veterinary Clinic of Shahid Bahonar University of Kerman. The vital signs and haematologic indices of the animal were normal. According to the history and clinical signs, mineral deficiencies, infestations with external parasites or endocrinopathy were suspected. Laboratory examinations of skin scrapings ruled out external parasites. Skin biopsy confirmed parakeratosis, which could be attributed to zinc deficiency. Zinc sulphate (250 mg, daily) was administered orally for 4 weeks. The clinical signs subsided after 4 weeks of treatment.

A 3-month-old short haired pointer with crusty local alopecia around the eyes was presented to Small Animal Hospital of Tehran University. Scraping and biopsy were obtained from lesions of affected area. Notoedres sp. was diagnosed in skin scraping by parasitologic examination. Furthermore, histopathology of lesions demonstrated moderate hyperplastic epidermis, parakeratosis and acanthosis.