Effect of breed on fattening performance, slaughter and meat quality characteristics of Awassi and Morkaraman lambs

The influence of breed on fattening performance, slaughter and meat quality traits was studied in Awassi and Morkaraman male lambs at approximately 8 months of age. All of the groups were fed a diet consisting of concentrate mixture offered ad libitum, and 300 g of grass hay per lamb per day during 60-day fattening period. Initial live weight, final live weight, daily weight gain and feed conversion efficiency (concentrate and hay consumption for 1 kg of live weight gain) were 39.63 kg, 55.08 kg, 0.258 kg and 6.37 for Awassi; 40.54 kg, 55.58 kg, 0.234 kg and 6.77 for Morkaraman, respectively. The effect of breed on fattening performance and slaughter traits except for LD area was not significant. In addition, meat colour parameters (L = lightness, a = redness, b = yellowness, H = hue angle and C = chroma), pH values, drip loss and sensory attributes were not affected by breed in present study. A significant muscle effect was observed for instrumental measurements of some meat quality characteristics as meat colour parameters (L, a and C), collagen, drip loss, pH, moisture and protein content, WBS, and for some sensory attributes (tenderness, juiciness, acceptability and number of chewing). Results of this study indicate that fattening performance, slaughter and meat quality traits were similar between Awassi and Morkaraman male lambs.     

Crossbreeding parameters of general immune response traits in White Leghorn chickens

Crossbreeding parameters of immune response traits were estimated from a set of well characterized crossbred populations derived from three chicken lines selected over 12 generations for three different general immune response traits and their F1, F2 and backcrosses. The three traits investigated were the selection criteria from each of the lines, i.e. antibody response to the Newcastle disease virus vaccine 3 weeks after vaccination (ND3), cell-mediated immune response (response to phytohemagglutinin, PHA) and phagocytic activity measured as carbon clearance (CC). Crossbreeding parameters included direct and maternal additive line effects, direct and maternal heterosis as well as direct epistatic recombination loss. They were estimated as linear combinations of genetic group effects estimated using animal model methodology. Significant line differences were obtained for ND3 and, to a lesser extent, CC. They were mainly due to direct effects, maternal effects being significant for none of the 3 traits. Significantly negative direct heterosis effects were also observed for ND3 and CC, but not for PHA. Maternal heterosis effects were not estimated for CC. They were non significant for PHA, and negative and significant (− 0.78 ± 0.24) for ND3. The significant favourable recombination gain estimated for ND3 (3.21 ± 0.88) indicates that epistatic interactions could be important for this trait.The present work shows that it was worthwhile to complete second generation crosses to be able to assess to what extent immunity gained by selection is maintained in advanced crossbred generations, and to compare the transmission of immune traits implicated in different aspects of immunity.     

The use of multivariate analysis to characterize carcass and meat quality of goat kids protected by the PGI “Cabrito de Barroso”

Fifty five suckling kids from three genotypes and two sexes protected by the PGI “Cabrito de Barroso” European quality label were used in this experiment. Carcass quality was assessed using indices from carcass measurements, dressing percentages, refrigerated losses, higher priced joints proportion and tissue composition of the carcass. Meat pH, colour, total pigment, fat, dry matter, collagen determinations (total and soluble), cooking losses and shear force estimated in longissimus thoracis et lumborum (LTL) and gluteobiceps (GB) muscles were used to characterize meat quality. Principal component (PC) analysis was performed in order to examine carcass quality traits (n = 16) and meat quality (n = 16) traits. The five first principal components (PCs) explained about 86% of the total variability for carcass quality and 75% of the total variability for meat quality. Compactness indices of carcass and leg, carcass weight and subcutaneous fat were the most effective variables for the PC1, whereas the higher priced joints proportion, muscle proportions of the higher priced joints and of the carcass and the muscle and bone ratio were useful to define the PC2. The first PC of the meat quality parameters was characterized by colour traits (L, b, a, C, H and total pigment) whereas collagen determinations (total collagen and collagen solubility) defined the second PC. When the carcass quality data were projected on the plane defined by the first two PCs, two separate groups of points appeared, corresponding to the animals with slaughter live weight higher or lower than 10 kg. The distribution of the meat quality data on the plane defined by the first two PCs allowed the identification of two separate groups, corresponding to the muscles GB and LTL. The differences between genotypes tend to be small and related to slaughter live weight, which implies certain constancy in carcass and meat quality of the PGI “Cabrito de Barroso”.     

Effects of transportation during the hot season and low voltage electrical stimulation on histochemical and meat quality characteristics of sheep longissimus muscle

The effect of transportation during the hot season (42 °C) and low voltage electrical stimulation on physiological, histochemical and meat quality characteristics of Omani sheep was studied. Forty intact male sheep were divided into two equal groups: 3 h transported or non-transported. The non-transported group remained in holding pens for 48 h prior to slaughter, while the transported group was transported 300 km (approximately 3 h) in an open truck under solar radiation on the day of slaughter. Blood samples were collected from the animals before loading and prior to slaughter. Fifty percent of the carcasses from each group were randomly assigned to low voltage (90 V) at 20 min postmortem. Temperature and pH decline of the left longissimus thoracis muscle were monitored. Ultimate pH, WB-shear force, sarcomere length, myofibrillar fragmentation index (MFI), expressed juice, cooking loss and color L, a, b were measured on samples from both sides muscles collected at 24 h postmortem at 3–4 °C. The transported sheep had significantly higher plasma cortisol (P < 0.01), adrenaline, nor-adrenaline and dopamine concentrations (P < 0.05) than non-stimulated animals. Electrical stimulation resulted in a significantly (P < 0.05) more rapid pH fall in muscle during the first 12 h after slaughter. Muscles from electrically-stimulated carcasses had significantly (P < 0.05) lower pH values, longer sarcomere length, lower shear force value, higher expressed juice, MFI and lighter L than those from non-stimulated ones. The muscle samples from the transported sheep had significantly (P < 0.05) smaller and lower proportion of Types I and IIA fibers than those from the non-transported group. This study indicated that pre-slaughter transport at high ambient temperatures can cause noticeable changes in physiological and muscle metabolism responses in sheep. Electrical stimulation improved meat quality characteristics, which indicate that meat quality of transported sheep can be improved by electrical stimulation.     

Interactions between the naked neck gene, sex, and fluctuating ambient temperature on heat tolerance, growth, body composition, meat quality, and sensory analysis of slow growing meat-type broilers

Influence of the Naked Neck gene, NA, on heat tolerance was evaluated in slow growing meat-type chickens in interaction with sex. Standard male Ross broilers were used as rapid growth controls. Fluctuating temperature was used to simulate day–night variations, i.e. 17 °C to 23 °C in normal and 27 °C to 33 °C in hot conditions. Male and female chickens were weighed twice and once a week, respectively, and Gompertz function was fitted to our data to calculate theoretical age at 1 kg (A1K) and 2 kg (A2K). Carcass, abdominal fat, breast and leg yields were measured (CY, AFY, BRY, and LY). Meat quality was evaluated 24 h post-mortem with pH and colour (L, a, b) of the breast, and 72 h post-mortem with breast meat drip loss (DL). Rectal temperature and its variation were measured at the maximum and minimum ambient temperature at 1 and 2 kg (RT2_min, RT2_max, and ΔBT_2 kg). Hematocrit (HCT, ΔHCT) were measured at the same stages. Organoleptic characteristics of breast and leg muscles were studied for females from both ambient temperatures.Significant genotype × sex × temperature interaction was observed for A2K, AFY, RT2_max, ΔBT_2 kg, and ΔHTC_2 kg. Hot condition did not affect ΔBT_2 kg and A2K in homozygous NA birds; ΔBT_2 kg was markedly increased in all other genotypes for males but not for females. Significant genotype × environment interactions were found only for A2K and CY. Sex × temperature interactions were found for all traits except for A1K, b, pH, and ΔHCT_2 kg. In both conditions, males reached 2 kg at the same age (69 d) while females reached this weight 11 d latter in hot than in normal condition. Heat decreased CY in males (− 1.0%) and increased it in females (+ 1.4%). Meat was paler in males and darker in females in the hot condition leading to a difference in meat brightness between males and females only in the hot condition. Concerning sensory analysis, genotype × temperature interaction was significant for meat consistence, both in leg and breast muscles.Effects of the NA gene on susceptibility to heat stress were smaller in slow growing animals than in broilers. However, heat tolerance was still improved in homozygous NA slow growing birds, as shown by the limited change in diurnal variation of body temperature. Furthermore, the NA gene improved breast meat percentage.In contrast to broilers, where females should be recommended for production in hot climates, the present study would rather suggest that naked neck males from slow-growing meat-type ‘label’ chicken lines should be preferred.     

Effect of castration on productive performance, carcass characteristics and meat quality of Iberian pig females reared under intensive management systems

Sixty crossbred (Iberian dam × Duroc sire) females, 80 days of age (17.6 ± 0.13 kg body weight, BW), was used to investigate the effect of castration on productive performance, carcass and meat quality and fatty acid profile of backfat (BF). There were 2 treatments (intact females, IF; castrated females, CF) and 5 replicates of 6 pigs per treatment. Pigs were reared indoor under an intensive production system, ovariectomized at 92 days of age (26.1 ± 0.19 kg BW) and slaughtered at 267 days of age (143.6 ± 6.49 kg BW). Meat samples were taken at longissimus dorsi muscle at the level of the last rib and BF samples were taken at the tail insertion. For the entire experiment (18 to 144 kg BW), IF ate less feed and were more efficient than CF (P < 0.05). Also, IF had less carcass yield (P < 0.01) and fat thickness at the gluteus medius muscle (P < 0.05) and tended to have lower backfat depth (P < 0.10) than CF. However, IF had higher shoulder yield at 2 and at 24 h post mortem (P < 0.05) and after trimmed (P < 0.10) than CF. The pH₂₄ of the semimembranosus muscle tended to be lower for IF than for CF. Also, IF had more moisture (710 vs. 691 g/kg) and less fat (66.4 vs. 91.2 g/kg) in the longissimus dorsi muscle than CF (P < 0.05). Meat from IF was more lightness (higher L value; P < 0.01), redder (higher a value; P < 0.001) and had more intensive color (higher c value; P < 0.001) than meat from CF. Backfat was more saturated in CF than in IF (P < 0.05), mostly because of the higher palmitic acid (P < 0.05) and the lower linolenic acid (P < 0.05) content. We conclude that intact females have better productive performance and shoulder yield but less carcass yield than castrated females and that castration does not improve meat quality. Therefore, when animal welfare, cost of castration, productive performance and carcass and meat quality traits are considered, the use of intact females rather than castrated females is recommended for the production of Iberian pigs reared under intensive management systems.     

Effect of energy restriction in interaction with genotype on the performance of growing rabbits: II. Carcass traits and meat quality

In this experiment the effect of digestible energy (DE) restriction on carcass traits and meat quality of rabbits selected divergently for body fat content was studied. Using a 2 × 3 factorial arrangement, Pannon White rabbits selected for high (HFAT) or low (LFAT) total body fat content were fed isocaloric diets between 4 and 12 weeks of age. Energy restriction was achieved by reducing the daily feed intake by 10% (M) and 20% (L) compared to the ad libitum fed group (H). Proportional to the reduction of feed intake the nutrient density of diets M and L was increased. Thus, the DE intake was reduced while the nutrient intake remained stable among the 3 dietary groups. Effect of genetic group on carcass traits and on meat quality parameters was less marked than DE restriction. Selection for high body fat content improved the dressing out percentage (58.3 and 57.3% in HFAT and LFAT respectively; P < 0.01), and reduced the percentage of the full gastrointestinal tract to slaughter weight (13.7 and 14.3% in HFAT and LFAT respectively; P < 0.05). Reduction of DE intake decreased the body weight and the weight of the chilled and reference carcass (P < 0.001), while it had no effect on dressing out percentage. In group H the percentage of fore part to reference carcass was higher (29.7 vs 29.0%; P < 0.01) while that of the hind part was lower than in group L (37.0 vs 38.2%; P < 0.001). The Longissimus lumborum meat from HFAT rabbits exhibited a lower content of moisture (76.1 and 76.5% in HFAT and LFAT respectively; P < 0.01) as well as lower L (53.5 and 54.4 in HFAT and LFAT respectively; P < 0.05) and b (0.42 and 0.81 in HFAT and LFAT respectively; P < 0.05) colour values. When compared with ad libitum fed rabbits, those restricted at 20% (L) exhibited a higher content of moisture (76.9 vs 75.8%; P < 0.01), as well as higher pHu (5.87 vs 5.73; P < 0.01) associated with lower cooking loss (17.8 vs 19.1%; P < 0.05). L rabbits also produced lower values of redness (a, 2.21 vs 3.35; P < 0.01) and yellowness (b, 0.23 vs 0.91; P < 0.01). No effect of the divergent selection for body fat content on the total lipid percentage and on most of the fatty acids in the meat of the hind leg was found. DE restriction resulted in lower SFA (L: 32.1 vs H: 35.8%; P < 0.01) and MUFA (L: 21.0 vs H: 28.6; P < 0.01) but higher PUFA contents (L: 45.5 vs H: 34.9%; P < 0.01) in the hind leg meat.     

Effects of dietary Cu, Mo and S on urinary Cu and Zn excretion in Simmental and Angus cattle

This study determined the effects of dietary copper (Cu), molybdenum (Mo) and sulphur (S) on urinary Cu and zinc (Zn) excretion in cattle. Four Simmental and four Angus heifers were fed low (L) or high (H) levels (mg/kg DM) of Cu (5, 40), Mo (1, 10) and S (0.2, 0.5%). Initially two of each breed was fed either LCu or HCu (2 mo). Then all eight animals were fed sequentially LCuHS (1.5 mo), HCuHS, HCuHMo and HCuHMoHS (2 mo each). Simmental had a higher urine flow, increased concentration and total excretion of urinary Cu and Zn compared to Angus, but only total Zn excretion was significantly higher. Urinary Cu excretion was greatest with the HCuHMoHS diet. Urinary Zn excretion significantly increased with HS but not HS in combination with HMo and/or HCu. This study, together with previously reported biliary excretion, allows a direct comparison of urinary and biliary Cu and Zn excretion responses to dietary Cu, Mo and S.     

Identification of avian strains of Pasteurella multocida in India by conventional and PCR assays

The prevalence of capsular and somatic serotypes were studied among 123 Pasteurella multocida strains isolated from chickens (n = 94), ducks (22), quails (4), turkeys (2) and geese (1) from different geographical regions of India. All strains exhibited similar cultural and morphological characteristics. Ninety-two of the isolates belonged to serotype A:1, the most prevalent serotype, with serotypes A:3, A:1,3, D:3 and F:3 having two isolates each. Only one isolate was positive for serotypes A:4 and D:1. Twenty isolates were untyped. A multiplex capsular PCR assay generated amplicons of sizes 460, 1044, 657 and 854 bp in 106 isolates identified as capsular serotype-A, 15 in serotype D and two in serotype F. Capsular types B and E were not detected in any of the avian isolates studied. The present findings suggest that a multiplex capsular PCR assay may be suitable for the rapid initial identification serotypes P. multocida during epidemiological studies of fowl cholera.     

Effect of supplementation with MgCO3 and l-Tryptophan on the welfare and on the carcass and meat quality of two halothane pig genotypes (NN and nn)

Sixty-one animals with different Halothane genes (homozygous halothane positive, n = 34; and homozygous halothane negative, n = 27) were fed with three diets (control group, with no supplement; magnesium (Mg) group with 1.28 g MgCO₃/kg and tryptophan (Trp) group with 5 g l-Trp/kg) during the last 5 days before slaughter. Animals were submitted to minimal stress antemortem conditions. Pig behaviour was recorded at the experimental farm, raceway to the CO₂ stunning system and during the stunning period. Corneal reflexes were recorded after stunning as well. There were no differences in feed intake among diets (P > 0.05) during the 5 days of treatment. The halothane positive (nn) group had lower intake than the halothane negative (NN) group (P < 0.01). The behaviour of the pigs in the raceway did not differ (P > 0.05) among treatments or halothane genotype. A significant (P < 0.001) interaction diet  halothane was found in the time to appear the first retreat attempt during the exposure to the CO₂ system. In the nn group, the time of performing the first retreat attempt was later in the Mg (P < 0.05) than the control group. Moreover, in the Mg group, the nn had a later (P < 0.05) first retreat attempt than the NN. Thus, Mg supplementation could have a positive effect on welfare of nn pigs. The nn had a lower proportion of animals that showed corneal reflexes after stunning than NN, indicating a higher effectiveness of the stunning method in nn pigs. Neither Mg nor Trp affected carcass quality and meat quality parameters, although significant differences were found between genotypes.     

Simulation of foot-and-mouth disease spread within an integrated livestock system in Texas, USA

We used a simulation study to assess the impact of an incursion of foot-and-mouth disease (FMD) virus on the livestock industries in an 8-county area of the Panhandle region of Texas, USA. The study was conducted in a high-density livestock area, with an estimated number of cattle on-feed of approximately 1.8 million. We modified an existing stochastic, spatial simulation model to simulate 64 scenarios for planning and decision-making. Our scenarios simulated four different herd types for the index herd (company feedlot, backgrounder feedlot, large beef, backyard) and variations in three mitigation strategies (time-of-detection, vaccine availability, and surveillance during disease control). Under our assumptions about availability of resources to manage an outbreak, median epidemic lengths in the scenarios with commercial feedlot, backgrounder feedlot, large beef and backyard index herd types ranged from 28 to 52, 19 to 39, 18 to 32, and 18 to 36 days, respectively, and the average number of herds depopulated ranged from 4 to 101, 2 to 29, 1 to 15 and 1 to 18, respectively. Early detection of FMD in the index herd had the largest impact on reducing (13–21 days) the length of epidemics and the number of herds (5–34) depopulated. Although most predicted epidemics lasted only 1–2 months, and <100 herds needed to be depopulated, large outbreaks lasting 8–9 months with up to 230 herds depopulated might occur.     

Development and application of G1-ELISA for detection of antibodies against bovine ephemeral fever virus

The gene encoding antigenic site G₁ of bovine ephemeral fever virus (BEFV) was highly expressed in the host cell Escherichia coli. An indirect G₁-ELISA with the recombinant protein as the coating antigen was established to detect antibodies against BEFV. The result revealed that the optimal concentration of the coated antigen was 0.5 μg/well and the dilution of serum was 1:20. It was optimal that sera with P/N value  2.2 were considered positive, P/N value  2.0 negative, and between 2.0 and 2.2 ambiguous. The G₁-ELISA method gave a sensitivity of 97.6% and a specificity of 98.6% by testing 590 field serum samples. These results suggest that the G₁-ELISA may be a good alternative tool for seroepidemiological surveys.     

Effects of supplemental humic substances on growth performance, blood characteristics and meat quality in finishing pigs

A total of forty-eight finishing pigs were used to determine the effects of humic substances (HS) on growth performance, blood characteristics, and meat quality. The finishing pigs were assigned randomly by weight to three treatments. The dietary treatments included: 1) Control (CON; basal diet), 2) HS1 (basal diet + 5% humic substances) and 3) HS2 (basal diet + 10% humic substances). Results of the whole experimental period showed that addition of 10% HS to the diet, significantly increased average daily gain (ADG) and gain/feed (G:F) (P < 0.05). At the end of the experiment, the relative lymphocyte counts (% of total white blood cells) of pigs fed HS2 diet were higher (P < 0.05) than that of pigs fed CON diet. The Minolta color parameter a of pigs fed HS2 was similar to that of pigs fed HS1, however, it was higher (P < 0.05) than that of pigs fed CON diet. The inclusion of either 5% or 10% HS significantly decreased backfat thickness (P < 0.05). The marbling score was increased significantly (P < 0.05) when diets were supplemented with HS at a level of 10%. The results of this study suggest that HS might be utilized as a feed additive in the diet. It could improve growth performance, relative lymphocyte counts and meat quality.     

Use of a hand-held meter for detecting subclinical ketosis in dairy cows

The Optium Xceed is a new hand-held meter for determining blood β-hydroxybutyrate (BHBA) and glucose in human medicine. The objective of this study was to compare BHBA and glucose results obtained using the hand-held meter with those results made with a laboratory method and to evaluate its usefulness as a cowside test in the diagnosis of subclinical ketosis (SCK) in dairy cows. Seventy-eight blood samples from clinically healthy Holstein cows between 5 and 60 days post-calving were analysed. BHBA and glucose values were significantly higher with the hand-held meter versus laboratory methods. Correlation coefficients (r) for BHBA and glucose with the Optium Xceed versus laboratory methods were 0.97 and 0.63, respectively. Based on Bland–Altman plot and Passing–Bablok regression, agreement between two methods was good for BHBA but the agreement for glucose was only fair. When SCK was defined as plasma BHBA levels 1200 μmol/L, the sensitivity and specificity of the hand-held meter ketone testing in determining SCK were 85% and 94%, respectively. Raising the threshold of the laboratory method to 1400 μmol/L, the sensitivity and specificity incremented to 0.90 and 0.98, respectively.In conclusion, the blood ketone-monitoring device can be used as a rapid and reliable diagnostic test to detect SCK under field conditions.     

Prevalence and severity of foot lesions in Danish Holstein heifers through first lactation

Several studies have shown that foot lesions and clinical lameness occur before first calving and develop further during the lactation period. Lameness may cause production losses, but the relationship between foot lesions, particularly in the claw horn, and lameness in heifers is unclear. The objectives of this study were to describe the development of and evaluate the relationship between lameness and foot lesions in Danish Holsteins before and after first calving. In a longitudinal study, 147 heifers were examined for lameness and foot lesions 2–5 times over an 18-month period. Lameness was assessed by means of a visual locomotion score and foot lesion severity was recorded.The prevalence of a locomotion score 3 was 25% before calving, and 90% at approximately 250 days in milk (DIM). Prevalence of moderate to severe sole haemorrhage (SH) was 27% before calving and 56% at 250 DIM, and that of moderate to severe white line lesion (WLL) 44% before calving with a peak of 70% at 200 DIM. There was one case of white line abscess but SH was seen throughout the entire study period. Digital dermatitis (DD) was prevalent prior to first calving (15%) and peaked at 39% at 0–100 DIM. Heel horn erosion (HHE) occurred in almost all cows (93–100%) and was strongly correlated with DD (r = 0.51). The correlation coefficient between SH and WLL was also high (0.42). The relatively high correlations between WLL and both DD and HHE were more surprising (0.38 and 0.35, respectively), those between SH and both DD and HHE were moderate (around 0.18). Interdigital dermatitis was significantly correlated with both HHE and DD, but completely unrelated to SH and WLL.The overall average locomotion score increased by about one-half of a score unit from 1 month prior to calving until 250 DIM, with a large difference between herds, although this was unsurprising as cows may alter their locomotion pattern with management factors (e.g. floor properties). DD and WLL were both associated with a locomotion score 3 but of the cows with severe WLL there was no clear association between a locomotion score 3 and DD. The highest locomotion scores occurred among cows with DD but without WLL.     

Monofrequency forced oscillation technique for the investigation of pulmonary function in calves: in vitro and in vivo studies

Parameters derived from the non-invasive and simple monofrequency forced oscillation technique were compared with classical parameters of ventilatory mechanics in order to assess its usefulness for the investigation of pulmonary function in calves. To facilitate this comparison, theoretical derivations were coupled with in vitro measurements, using an artificial lung model, and with in vivo studies. These studies compared the oscillatory resistance parameters (R_os and Re) and the respiratory system compliance (C_rs) against the classical pulmonary resistance (R_L) and the dynamic compliance (C_dyn), respectively. Ros and Re were highly correlated (r0·87) with R_L and the comparison between Crs and C_dyn gave a similarly high correlation (r0·88). Given its simplicity, its correspondence with classical parameters and its rapidity and reproducibility, monofrequency forced oscillation technique seems well suited for the investigation of pulmonary function under field conditions.     

Activation of equine neutrophils by phorbol myristate acetate or N-formyl-methionyl-leucyl-phenylalanine induces a different response in reactive oxygen species production and release of active myeloperoxidase

Neutrophil (PMN) contribution to the acute inflammatory processes may lead to an excessive generation of reactive oxygen metabolites species (ROS) and secretion of granule enzymes. We compared the effects of either phorbol myristate acetate (PMA) or N-formyl-methionyl-leucyl-phenylalanine (fMLP) in combination with a pre-treatment by cytochalasin B (CB) on the production of ROS and the release of total and active myeloperoxidase (MPO) by isolated equine PMNs. The ROS production was assessed by lucigenin dependent chemiluminescence (CL) and ethylene release by α-keto-γ-methylthiobutyric acid (KMB) oxidation. In the supernatant of activated PMNs, total equine MPO was measured by ELISA and active MPO by the SIEFED (Specific Immunologic Extraction Followed by Enzymatic Detection) technique that allows for the study of the interaction of a compound directly with the enzyme. The stimulation of PMNs with CB-fMLP only modestly increased the release of MPO, but more than 70% of released MPO was active. PMA stimulation markedly increased the production of ROS and release of MPO, but more than 95% of released MPO was inactive. When PMNs were pre-incubated with superoxide dismutase (SOD) prior to PMA activation, the lucigenin enhanced CL, which is linked to the superoxide anion (O₂⁻) production, was much more decreased than KMB oxidation, linked to the hydroxyl-like radical production. The addition of SOD prior to the activation of PMNs by PMA also limited the loss of the activity of released MPO. These results confirm the key role of O₂⁻ generation in the ROS cascade in PMN and reveal its critical role on MPO inactivation.     

Liver blood flow and metabolic clearance rate of progesterone in sheep

To study the inverse relationship between feed level and concentrations of peripheral plasma progesterone, 36 ovariectomised ewes were fed rations at levels calculated to maintain liveweight (M). On the seventh day, the ewes were given an intravenous infusion of progesterone and the metabolic clearance rate (MCR) was calculated. The ewes were then randomly allotted to receive either , M or 2M rations for seven days at which time the infusion and blood sampling schedules were repeated. The mean (SE) MCR of infused progesterone in ovariectomised ewes fed either , M or 2M rations for seven days was 7·1 (0·59), 9·9 (1·64 and 13·0 (1·19) litre h⁻¹ kg⁻¹ of liveweight, respectively. Differences in MCR of progesterone between ewes fed and 2M rations were significant (P<0·05). The inverse relationship between level of feed intake and plasma progesterone concentration was attributed to differences in clearance rate of progesterone rather than to changes in the entry rate of the hormone into the blood.     

Congenital heart disease in boxer dogs: results of 6 years of breed screening

This prospective study was conducted to evaluate the prevalence and severity of ocular lesions in dogs with anemia (packed cell volume  20%) and/or thrombocytopenia (platelet count < 150,000/μL). Dogs were divided into four groups: (1) anemic (n = 17); (2) thrombocytopenic (n = 36); (3) anemic and thrombocytopenic (n = 24); and (4) healthy controls (n = 26). The prevalence of ophthalmic lesions in these four groups was 12%, 42%, 42% and 0%, respectively. Anemia was not associated with the presence of ocular lesions (P = 0.41) or their severity. Thrombocytopenia was significantly associated with the presence of ocular lesions (P = 0.0016) and with their severity (P = 0.017). We conclude that thrombocytopenia, but not anemia, is associated with ocular lesions in dogs.     

Kinetic disposition, systemic bioavailability and tissue distribution of apramycin in broiler chickens

Apramycin was administered to chickens orally, intramuscularly and intravenously to determine blood concentration, kinetic behaviour, bioavailability and tissue residues. Single doses of apramycin at the rate of 75 mg kg⁻¹ body weight were given to broiler chickens by intracrop, i.m. and i.v. routes. The highest serum concentrations of apramycin were reached 0·20 and 0·76 hours after the oral and i.m. doses with an absorption half-life () of 0·10 and 0·19 hours and an elimination half life () of 1·22 and 2·31 hours respectively. The systemic bioavailability was 2·0 and 58 per cent after intracrop and i.m. administration, respectively, indicating poor absorption of the drug when given orally.Following i.v. injection, the kinetics of apramycin was described by a two-compartment open model with a () of 1·5 hours, () of 2·1 hours, V_d(ss) (volume of distribution) of 4·82 litre kg⁻¹ and C1_(B) (total body clearance) of 1·88 litre kg⁻¹ hour⁻¹. The serum protein-binding of apramycin was 26 per cent.The highest tissue concentrations of apramycin were present in the kidneys and liver. No apramycin residues were detected in tissues after six hours except in the liver and kidneys following intracrop dosing and kidneys following i.m. administration.