Genotype by climate interaction in the genetic evaluation for growing traits of Braunvieh cattle in Mexico

The objective of this study was to determine the magnitude of genotype by climate interaction (GCI) in the national genetic evaluation for weaning (WW) and yearling (YW) weights of Mexican Braunvieh cattle. The numbers of performance records and animals in the pedigree were 12,364 and 25,173 for WW, and 7,991 and 18,072 for YW, respectively. Performance records were clustered based on climatological variables into: dry tropic (DT), wet tropic (WT), and temperate (TE) climates. Animal models were used to estimate genetic parameters and predict breeding values in each of the climates. Bivariate analyses were carried out for pairwise combinations of climates on each trait, considering the same trait in different climates as a different trait. Criteria to evaluate GCI were genetic correlations (r _g), correlations between predicted breeding values (r _BV), and frequencies of coincidence (FC) in the ranking of the top 25 sires. Results of comparisons between pairs of climates were variable, depending on specific cases. For WW, the r _g, r _BV, and FC ranged from ?0.36 to 0.84, ?0.60 to 0.97, and 0.16 to 0.92, respectively; whereas for YW, they fluctuated between 0.23 and 0.99, 0.33 and 1.00, and 0.60 and 1.00, respectively. For both traits, the results suggest absence of GCI between DT and TE; however, GCI was detected in the other pairs of climates, where WT was involved. To maximize genetic progress, the joint genetic evaluation should be performed only for animals with performance data in DT and TE, whereas a separated evaluation is suggested for animals with performance records generated under WT conditions.     

Cetirizine in horses: pharmacokinetics and effect of ivermectin pretreatment

The pharmacokinetics of the histamine H(1)-antagonist cetirizine and the effects of pretreatment with the antiparasitic macrocyclic lactone ivermectin on the pharmacokinetics of cetirizine were studied in horses. After oral administration of cetirizine at 0.2 mg/kg bw, the mean terminal half-life was 3.4 h (range 2.9-3.7 h) and the maximal plasma concentration 132 ng/mL (101-196 ng/mL). The time to reach maximal plasma concentration was 0.7 h (0.5-0.8 h). Ivermectin (0.2 mg/kg bw) given orally 1.5 h before cetirizine did not affect its pharmacokinetics. However, ivermectin pretreatment 12 h before cetirizine increased the area under the plasma concentration-time curve by 60%. The maximal plasma concentration, terminal half-life and mean residence time also increased significantly following the 12 h pretreatment. Ivermectin is an inhibitor of P-glycoprotein, which is a major drug efflux transporter in cellular membranes at various sites. The elevated plasma levels of cetirizine following the pretreatment with ivermectin may mainly be due to decreased renal secretion, related to inhibition of the P-glycoprotein in the proximal tubular cells of the kidney. The pharmacokinetic properties of cetirizine have characteristics which are suitable for an antihistamine, and this substance may be a useful drug in horses.     

Recombinant bovine interferon-gamma enhances expression of class I and class II bovine lymphocyte antigens

Recombinant bovine interferon-gamma augments expression of class I and class II histocompatibility antigens on the surface membrane of bovine lymphocytes. Immunofluorescence techniques using a series of monoclonal anti-HLA antibodies demonstrate that this enhancement is detectable as early as 24 h after incubation with rBoIFN, while maximum surface expression is obtained within 3-5 days. A concentration as low as 10 units of rBoIFN is effective. Such results may be useful for characterizing the BoLA gene products.     

Determination of the dry matter disappearance and the crude protein degradability of the formaldehyde treated feeds in the rumen by in situ method

Sunflower cake (SC), horse bean (HB), and alfalfa meal (AM) were treated with rising doses of formaldehyde (F) from 0.0, 0.2 ... 2.0 g F per 100 g crude protein. We have followed the differences of crude protein solubility, its degradability and disappearance of dry matter in the rumen as well as the amount of reversible bonded F from the F dose. With AM it was found a significant influence of ADF on the degradability and on the amount of acid-labile bonded F and/or on the decrease of N solubility. From the total N content the share of soluble nitrogen decreased in SC by 31%, HB by 24%, and in AM only by 12.5%. With the increase of the F dose its protective effect on proteins against the degradability mainly in SC and HB also rose significantly. The degradability of AM protein was influenced more by the incubation time than by the effect of treatment. The degradability of the SC proteins fell from 95% with untreated to 27% treated with the maximum dose. With AM it fell slowly from 84% to 74% by the determination coefficient R2 = 0.77. It was observed a marked decrease in HB only from the dose of 1.28% F. The changes in dry matter disappearance were similar to the changes in crude protein degradability and to the changes of solubility in SC and AM. The in situ method proved very suitable for the determination of the extent of degradability of the feed proteins in the rumen.     

The distribution and chemical coding of neurons in the celiac-superior mesenteric ganglion complex supplying the normal and inflamed ileum in the pig

The present study investigated the chemical coding of neurons in the celiac-superior mesenteric ganglion complex supplying the normal (n=4) and inflamed (n=4) ileum (chemically-induced inflammation) in juvenile pigs using retrograde tracing combined with immunohistochemistry. Ileum-projecting neurons (IPN) were predominantly distributed in the left and right superior mesenteric pools of the ganglion. The majority of them were adrenergic (tyrosine hydroxylase-positive) and also contained neuropeptide Y, somatostatin or galanin. No clear-cut differences in the distribution and chemical coding of IPN were found between normal and inflamed pigs. However, in the inflamed group, the density of peptidergic, IPN-associated nerve fibres was higher than that found in the control group.     

Ixodid ticks parasitizing Iberian red deer (Cervus elaphus hispanicus) and European wild boar (Sus scrofa) from Spain: geographical and temporal distribution

Commercial hunting of Spanish wild ungulates has made them an important economic resource. Wild ungulates may have an important role in the maintenance of ixodid tick populations, and also as reservoirs of pathogens. We studied the ixodid ticks that parasitize Iberian red deer and European wild boar from Spain. Ixodid ticks (n=6,336) were collected from 431 Iberian red deer and 142 wild boar in different regions of Spain. We found 10 different ixodid tick species parasitizing Iberian red deer, mainly Hyalomma marginatum marginatum (63.7%), Rhipicephalus (Boophilus) annulatus (7.9%) and R. bursa (7.5%). R. (Boophilus) annulatus was only collected in the province of Cádiz (southern Spain). We found 8 ixodid tick species on the wild boar, mainly Hy. m. marginatum (68.7%), R. bursa (14.6%) and Dermacentor marginatus (9.3%). We found one adult Hy. marginatum rufipes and one adult Hy. anatolicum excavatum parasitizing wild boar from south-central Spain. Mean prevalence of ixodid ticks was 41.3+/-0.08% (n=475) and 31+/-0.09% (n=284) and intensity of parasitization was 13.9+/-0.2 (n=283) and 13.6+/-0.3 (n=130) ticks/animal for Iberian red deer and wild boar, respectively. Only 5 of the 13 ixodid tick species found were shared by Iberian red deer and wild boar. This finding could indicate a host preference when Iberian red deer and wild boar share common habitats. In both Iberian red deer and wild boar from south-central Spain the monthly relative frequencies of Hy. m. marginatum and R. bursa presented an inverse pattern. The highest Hy. m. marginatum relative frequencies coincided with the lowest R. bursa relative frequencies along the year. R. bursa and I. ricinus were present in areas from northern to southern Spain while Hyalomma sp. and D. marginatus were exclusively collected in the two southern thirds of Spain. Haemaphysalis sp. and D. reticulatus were collected in northern Spain. Hy. m. marginatum and R. bursa were present during the whole year in red deer and wild boar from south-central Spain, showing more than one life cycle per year. These results are important for understanding the role of wild ungulates in the maintenance of tick infestations and to improve tick control programmes.     

Leg health and performance of broiler chickens reared in different light environments

1. The effects of light source and intensity on leg health and performance of female ROSS 308 broiler chickens were investigated in a 2 x 2 experimental design (8 groups of 275 chicks) of two light sources (Osram biolux and Osram warm-white) and two light intensities (5 and 100 clux, adjusted to fowl-perceived illuminance). 2. At 41 d of age, body weight, gait-score, footpad dermatitis and hock-burn were measured on 50 birds from each light environment. In addition, weekly feed intake and body weight were determined on a group basis and mortality was recorded continuously. 3. The light environment did not affect the severity of the gait-score or hock-burns. The risk of moderate to severe lameness and hock-burns increased with body weight. Birds weighing more than 2400 g had an increased probability of moderate footpad lesions in biolux light. 4. Weight and gait-score, as well as gait-score and hock-burn were positively correlated. Podo-dermatitis was weakly correlated with hock-burn, which contradicts earlier findings. The light environment did not affect feed intake, body weight or mortality. 5. The light sources and intensities employed in this study did not adversely affect production or leg health of broiler chickens reared semi-commercially.     

Characterization of Cryptosporidium spp.--recent developments and future needs

Cryptosporidia, widely distributed protozoan parasites of vertebrates have recently attracted increasing interest due to several serious waterborne outbreaks, the life-threatening nature of infection in immunocompromised patients, and the realization of economic losses caused by these pathogens in livestock. Genetic polymorphism within Cryptosporidium spp. is being detected at a continuously growing rate, owing to the widespread use of modern molecular techniques. The aim of this paper is to review the current status of taxonomy, genotyping, molecular phylogeny, and characterization of cryptosporidia, and to highlight the need for polyphasic typing, i.e. an integrated approach comprising standardized morphologic, biologic, and molecular methods for describing Cryptosporidium species and isolates, and for establishing "virtual" reference strains.     

Use of volumetric capnography to identify pulmonary dysfunction in horses with and without clinically apparent recurrent airway obstruction

OBJECTIVE: To investigate whether volumetric capnography indices could be used to differentiate between horses without recurrent airway obstruction (RAO) and horses with RAO that were in clinical remission or that had clinically apparent RAO. ANIMALS: 70 adult Swiss Warmblood horses (20 used for pleasure riding and 50 used for dressage or show jumping). PROCEDURE: Horses were allocated to 4 groups on the basis of history, clinical signs, results of endoscopy, and cytologic findings (group 1, 21 healthy horses; group 2, 22 horses with RAO that were in remission; group 3, 16 horses with mild RAO; group 4, 11 horses with exacerbated RAO). Expiratory volume and CO2 curves were recorded by use of a computerized ultrasonic spirometer. Volumetric capnograms were plotted, and derived indices were calculated. RESULTS: Dead-space volume (VD) was calculated by use of the Bohr equation (VD(Bohr)) and for physiologic VD (VD(phys)). Ratios for VD(Bohr) to expiratory tidal volume (VT) and VD(phys) to V(T) as well as an index of effective CO2 elimination were significantly different among groups of horses. Age and use of the horses also significantly affected volumetric capnography indices. CONCLUSIONS AND CLINICAL RELEVANCE: Ratios of VD(Bohr) to VT and VD(phys) to VT as well as an index of effective CO2 elimination were sufficiently sensitive measures to distinguish between healthy horses and horses with RAO in remission. To optimize the ability of volumetric capnography indices to differentiate among horses in heterogeneous populations, it is important to account for effects of age and specific use of the horses.