Determination of biogenic amines in aerobically stored beef using high-performance thin-layer chromatography densitometry

The aim of this study was to develop a high-performance thin-layer chromatography densitometry method to simultaneously evaluate levels of different biogenic amines (BAs) in beef stored aerobically at 4°C. Steaks from M. longissimus thoracis et lumborum muscles were overwrapped with polyvinyl chloride film and stored for 0, 4, 7, and 10 days. For this purpose, the solvent system and pH for the derivatization of BAs with dansyl chloride were optimized. Moreover, this method was also validated for linearity, limits of detection and quantification, precision, and recovery. As found using this method in beef samples, spermine content decreased significantly after 7 days of storage, and tyramine and cadaverine were not detected until day 10.     

Paratuberculosis in cattle: a comparison of three serologic tests with results of fecal culture

Feces and blood were collected from cattle in 13 herds known to be infected with Mycobacterium paratuberculosis to evaluate a complement-fixation (CF) test, an agar gel immunodiffusion (AGID) test and an enzyme-linked immunosorbent assay (ELISA) for the serologic diagnosis of paratuberculosis. M. paratuberculosis was isolated from the feces of 36 of 192 cattle examined. Twenty-three culture-positive animals had CF test titers regarded as suspect or positive, 10 were positive by the AGID test and 34 were suspect or positive by the ELISA. Of the 156 culture-negative animals, the CF test agreed on 136, the ELISA on 129 and the AGID on 151.     

Effect of calcium-channel blockers and salbutamol on the isolated mare uterus — interaction with the calcium agonist Bay K 8644

The effects of nifedipine, verapamil and diltiazem were investigated in the isolated mare uterus in comparison with salbutamol. All the calcium-channel blockers and salbutamol inhibited the spontaneous, KC1- and electrically induced contractions; nifedipine and salbutamol were the most potent compounds. The calcium agonist Bay K 8644 (10(-8)-10(-6) mol/l) competitively antagonized the inhibitory effect of nifedipine (pA2 value = 8.54 +/- 0.06), whereas it was only slightly or totally ineffective against verapamil, diltiazem and salbutamol. These results indicate that calcium-channel blockers are potent inhibitors of mare uterine motility in vitro and emphasize the importance of Ca2+-related mechanisms in the control of uterine smooth-muscle contractility. Moreover, the validity of Bay K 8644 as a tool to distinguish classes of calcium-channel antagonists is confirmed.     

Serum concentrations of IGF-I in postpartum beef cows

Four experiments assessed changes in serum IGF-I under various physiologic conditions in postpartum cows. In Exp. 1, anestrous suckled cows (n = 25) were infused for 6 d with either saline or glucose at two different infusion rates. In Exp. 2, anestrous cows (n = 29) received either a saline (weaned and suckled controls) or 3 g/d phlorizin (weaned phlorizin) infusion for 3 d. Calves from the weaned groups were removed from 15 h before and throughout infusions. In Exp. 3, cycling suckled cows (n = 20) received prostaglandin F2 alpha (PGF2 alpha) when the 5-d saline or phlorizin infusion began. In Exp. 4, suckled cows (n = 20) had ad libitum access to feed or received 50% of control feed consumption from 30 to 40 d postpartum. Increasing glucose availability (Exp. 1) increased (P less than .05) serum IGF-I by 30 to 35%. IGF-I remained stable after weaning (Exp. 2) in phlorizin-infused cows (128.8 +/- 12.7 ng/ml), but increased (P less than .05) by 3 d after calf removal in weaned control cows (152.2 +/- 7.5 ng/ml). IGF-I also remained stable in phlorizin-infused cows following PGF2 alpha injection (Exp. 3), but increased in control cows by 2 d after PGF2 alpha (156.8 +/- 18.3 on d 2 vs. 133.7 +/- 9.8 ng/ml pre-injection; P less than .05) and remained elevated (P less than .05) during the periovulatory period. In cows receiving restricted feed intake (Exp. 4), IGF-I decreased by approximately 50% within 4 d of feed restriction (71.3 +/- 9.4 vs 137.4 +/- 16.6 ng/ml; P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of additional feed during late gestation on reproductive performance of sows: a cooperative study

A cooperative research study involving 1,080 litters was conducted at eight stations to determine the effects of additional feed during the last 23 d of gestation on reproductive performance of sows and on preweaning performance of their pigs. Primiparous and multiparous sows were fed fortified corn- or sorghum-soybean meal diets (14% crude protein). Control sows received 1.82 kg/d from March through November and 2.27 kg/d from December through February. Treated sows were fed an additional 1.36 kg of feed/d from d 90 of gestation to farrowing. Sows were allowed to consume the same diet ad libitum during a 21-d lactation. Additional feed in late gestation resulted in greater (P less than .001) sow weight gain from d 90 to d 110 of gestation (16.8 vs 9.0 kg) and greater (P less than .001) parturition-lactation weight loss (21.3 vs 16.4 kg). Total weight gain from breeding to 21 d of lactation favored sows that received extra feed (27.5 vs 22.7 kg; P less than .001). Sows receiving extra feed had more live pigs at farrowing (10.05 vs 9.71, P = .06) and at 21 d postpartum (8.35 vs 8.06, P = .09), and the pigs were heavier at birth (1.48 vs 1.44 kg, P = .003) and at 21 d (5.37 vs 5.20 kg, P = .006). Lactation feed intake and number of days from weaning to estrus were not affected by treatment. The results indicate that additional feed in late gestation improves reproductive performance in sows. In this study, the cost of an additional 31 kg of feed/sow was more than offset by the value of the additional sow weight gain (approximately 5 kg), the additional .3 of a pig/litter at weaning and the additional 2.6 kg of total litter weaning weight.     

Treatment of teat obstruction in a cow by transfer of oral mucosa and temporary implantation of an intraluminal tube

A dairy cow was examined because of extensive obstruction of a teat cistern. The teat was treated by surgical resection of scar tissue, transplantation of an oral-mucosal autograft, and temporary implantation of a silastic tube. The silastic tube became dislodged from the teat, and was surgically removed 30 days after the initial surgery. The cow subsequently had 2 normal lactations. Prior to the third postoperative lactation, the cow developed severe udder edema. During lactation, the surgically treated teat became hard and was difficult to milk. The cow was then culled.     

Phospholipid content of subcellular structures in skeletal muscles after halothane loading in Landrace swine in relation to mating variants and genotype

Membraneous phospholipids of subcellular structures were determined from the musculature of German Landrace pigs of the GDR, following exposure to halothane. Mating variants A (H+ male X H+ female), B (H+ male X H- female), and C (H- male X H+ female) were used for positive responders (MHS), while variants B, C, and D (H- male X H- female) were used for negative responders (MHN). Four phospholipid fractions were recorded from the muscle samples for mitochondria and microsomes (according to SR section). Differences between the MHS and MHN groups for the above fractions and without consideration of mating variants and genotype were not observed, although unambiguous responses were exhibited by all animals, either positive or negative to halothan. Significant differences with regard to the above phospholipid fractions were recordable only for variant A (MHS group) as compared to D (MHN), in other words, for the homozygous genotypes, once the above results had been rearranged within MHS and MHN along with different mating variants and genotypes. However, no unambiguous results were obtainable for the heterozygous genotypes of mating variants B and C. Possible underlying reasons are discussed in some detail. The results obtained from mating variants A and D are likely to confirm earlier findings and seem to suggest that the sarcoplasmic reticulum is the primary site of origin of susceptibility to halothane or malignant hyperthermia.     

Effect of lenperone hydrochloride on gastroesophageal sphincter pressure in healthy dogs.

Treatment of healthy dogs with the butyrophenone derivative, lenperone hydrochloride, at two different doses significantly decreased gastroesophageal sphincter pressure (GESP). No dose-related effect was identified. Individual variation in the response to lenperone hydrochloride was noted which was consistent on a day-to-day basis. Lenperone hydrochloride is unsuitable for chemical restraint of dogs undergoing esophageal manometry because it decreases GESP and because the magnitude of the decrease varies considerably between dogs.     

Growth and feed utilization by yearling horses fed added dietary fat

Twenty-four yearlings were used to evaluate the efficacy of feeding feed-grade fat to growing horses. All horses were started on trial at 13-months-of-age and were fed for 112 days. The experimental diets, containing similar nutrient-to-calorie ratios, were: 1) control (no added fat; 2) 5% added fat and; 3) 10% added fat. There was a trend for yearlings fed the 10% added fat diet to grow faster and eat less feed than those on the control diet. Data from this study indicate that feed-grade fat can be safely fed to growing horses. Feeding fat to yearlings stimulated growth and efficiency of feed utilization initially, but these effects were not maintained as the yearlings grew toward maturity.     

Molecular cloning of DNA from a bovine herpesvirus 1 strain isolated in Hungary

Molecular cloning of the HindIII fragments of bovine herpesvirus 1 (BHV-1) strain HB144, isolated from infectious bovine rhinotracheitis (IBR) in Hungary, and of an infectious pustular vulvovaginitis (IPV) reference strain (K22) is reported. So far 52% of the IBR viral genome and 28% of the IPV viral genome have been cloned. The analysis of differences between the strains is currently in progress.