Near infrared spectroscopy in large animals: Optical pathlength and influence of hair covering and epidermal pigmentation

The effects of epidermal pigmentation and hair covering on the relative transparency of various animal tissues to near infrared (NIR) light were examined, and the pathlengths of NIR light through tissues at four wavelengths in the NIR range were subsequently determined. Black hair covering and black or dark-coloured hooves prevented NIR light from penetration sufficient for conduction of pathlength or NIR spectroscopy measurements. Non-pigmented hair covering of the head did not appear to be a barrier to successful NIR light transmission. Tissues sufficiently transparent to NIR light had the differential path length factor (DPF, i.e. the ratio of the observed light pathlength and the geometric light source-detector separation) of NIR light determined by intensity modulated spectroscopy at the wavelengths 744, 806, 834 and 860 nm. Horse gluteal muscles had DPFs of 6.2, 6.2, 6.0, and 5.6, whereas forelimb muscles had DPF of 4.7, 4.4, 4.5 and 3.9 at the respective wavelengths. Sheep heads had DPF of 7.2 +/- 0.3, 5.8 +/- 0.5, 5.5 +/- 0.4 and 4.4 +/- 0.6 (+/- SEM) for the above respective wavelengths, of which the pathlengths all differed significantly from the other, except for between 806 and 834 nm, and 834 and 860 nm. The DPF of horse hooves were 4.8 +/- 0.1, 4.8 +/- 0.1, 4.7 +/- 0.1 and 4.4 +/- 0.1 (SEM) for the above noted wavelengths, of which the pathlength at 744 and 806 nm differed from the pathlength at 860 nm (P>0.05). These results show that NIRS is possible through lighter pigmented hair and epidermal tissues, and provide DPFs of horse feet and muscle and the sheep head that enables quantitative NIRS in these species

A Comparison of Po2, Pco2, Ph and Bicarbonate in Blood from the Carotid and Coccygeal Arteries of Calves

A technique is described for the subcutaneous deviation of the carotid artery into the jugular groove of calves weighing between 90 and 200 kg. This makes sampling arterial blood or chronic cannulation for further experimentation very easy. Values of oxygen tension, carbon dioxide tension, pH and bicarbonate concentration in blood sampled from the ventral coccygeal artery were compared with the values obtained in blood from carotid artery puncture. The high correlations observed indicate that blood samples from the ventral coccygeal artery can be used for measurement of blood gases and pH in calves

Comparaison du taux cellulaire et de la sensibilité antimicrobienne des germes responsables de mammite subclinique bovine entre les filières conventionnelle et biologique

A comparison of somatic cell count and antimicrobial susceptibility of subclinical mastitis pathogens in organic and conventional dairy herds.Bovine subclinical mastitis is the most important disease affecting dairy cows. The fluctuating increase in somatic cell count (SCC) that occurs causes major economic losses in dairy industry. This comparative study between conventional and organic dairy herds was conducted in the aim to better characterize which consequences might have different management practices on SCC but also on the frequency of pathogens isolated and their antimicrobial susceptibility. Four conventional and four organic herds, with bulk milk SCC >300x103cells/ml were selected, in which respectively 47 and 44 cows were investigated. Each quarter was sampled 3 times at 15 days interval for SCC, microbiological analysis and antimicrobial susceptibility. In both herd categories, major pathogens isolated were by order of importance Streptococcus uberis, Staphylococcus aureus and Streptococcus dysgalactiae with a great impact on SCC. Coagulase negative staphylococci were the most frequent minor germs and had a moderated but real impact on SCC. In certified organic dairy farms, the three most frequently isolated major pathogens were significantly more susceptible to antimicrobials in vitro. This study suggests that the limited use of antibiotics in organic dairy herds could explain, at least in part, the lower resistance obtained from analysed isolates.La mammite subclinique est une pathologie de première importance chez la vache laitière. L’élévation persistante du taux cellulaire qui en résulte engendre d’énormes pertes économiques pour toute la filière laitière. L’objectif de cette étude était de comparer les filières conventionnelle et biologique afin de déterminer les conséquences que des pratiques d’élevage différentes peuvent avoir sur les taux cellulaires ainsi que sur la fréquence des germes isolés et leur sensibilité aux antibiotiques. Quatre exploitations laitières conventionnelles et 4 biologiques avec des taux cellulaires de lait de tank >300x103 cellules/ml ont été sélectionnées, parmi lesquelles 47 et 44 vaches respectivement ont été investiguées. Chaque quartier a été prélevé 3 fois à 15 jours d’intervalle pour les analyses cellulaires, bactériologiques et de sensibilité aux antibiotiques. Quelle que soit la filière, les germes majeurs rencontrés étaient par ordre d’importance Streptococcus uberis, Staphylococcus aureus et Streptococcus dysgalactiae et leur impact sur le taux cellulaire était très important. Les staphylocoques coagulase négative étaient les germes mineurs les plus fréquents et avaient un impact sur le taux cellulaire non négligeable. La sensibilité moyenne aux antibiotiques testés in vitro était significativement plus élevée en filière biologique pour les trois germes majeurs les plus fréquemment rencontrés. Cette étude suggère que l’usage moins abondant des antimicrobiens dans les exploitations biologiques sélectionnées pourrait expliquer, du moins en partie, les moindres taux d’antibiorésistance retrouvés

Partitioning of pulmonary resistance in Friesian calves

Eight right cranial lobes of healthy Friesian calves were suspended in an airtight box. They were inflated at a constant transpulmonary pressure (Ptp) and ventilated from the outside by modifying pressures in the box with a quasi-sinusoidal pump at a frequency of 30 counts per minute. Peak-to-peak changes were 0.5 kPa. Lobar resistance (Rl) was partitioned into three components: central airway resistance (Rc), small airway resistance (Rp) and tissue resistance (Rt). Partitioning of R1 was realised at six different lung volumes. Minimal R1 was observed for a value of Ptp between 0.5 and 0.7 kPa. At a Ptp of 0.5 kPa, Rc, Rp, Rt represent 30, 15 and 55 per cent of R1, respectively. Lobar resistance increases at high and low lung volumes. Small airway resistance is small and independent of the level of lung inflation, except at low lung volumes where a marked increase is observed. Tissue resistance is relatively high and responsible for the increase of R1 at high lung volumes. Central airway resistance does not change significantly with lung volume

Comparative study of the body surface electrocardiogram in double-muscled and conventional calves.

The purpose of this work was to study electrocardiographic features of double-muscled beef cattle. Electrocardiograms were recorded on one to six occasions from each of a group of 18 conventional calves of the Friesian breed and 29 double-muscled calves of the Belgian White and Blue breed. Ages of the calves at the times of examination ranged from eight to 348 days. The Holmes semi-orthogonal lead system was used. The waves and interval durations and the tridimensional P, QRS, and T modal vector orientation and amplitude were calculated. The magnitude of the cardiac vectors was significantly lower and the ventricular waves and QT interval duration significantly shorter in the double-muscled than in the conventional calves. The P modal vector pointed significantly less downwards and the QRS modal vector pointed significantly more forwards and less up- and rightwards in the Belgian White and Blue, than in the Friesian group. Most of the observed differences might be a consequence of the bodily, and more specifically the thoracic, conformation of the former calves. However, the lower cardiac vector magnitude and shorter wave and interval durations might also reflect lower cardiac mass in the double-muscled subjects

Partitioning of upper airway resistance in Friesian and double-muscled calves.

Respiratory resistance in calves was partitioned in two components: upper airway resistance and pulmonary resistance. The former one was divided into naso-pharyngeal and laryngeal resistance. A comparison between seven healthy unsedated double-muscled calves of the Belgian White and Blue breed (BWB) and five healthy unsedated Friesian (F) calves was performed. Respiratory resistance was significantly greater in the BWB calves, due to the significantly higher values of the naso-pharyngeal and the laryngeal resistances. This finding might be related to the higher prevalence of laryngitis in this bree

Selective blockade of NF-kB activity in airway immune cells inhibits the effector phase of experimental asthma

peer reviewedaudience: researcher, professiona

Pulmonary Function Values and Growth in Belgian White and Blue Double-Muscled Cattle

Seventy-five double-muscled cattle of the Belgian white and blue breed, two days to 50 months old and weighing 45 to 680 kg, were investigated. Transpulmonary pressure changes, measured with an oesophageal balloon, variations of air flow and volume at the mouth were obtained during spontaneous breathing to calculate pulmonary function data. Oxygen and carbon dioxide tensions in arterial blood were also recorded. Growth related changes of the pulmonary function values were similar to those observed in other bovine breeds. Total pulmonary resistance, specific total pulmonary resistance, viscous work, power of breathing, specific viscous work, respiratory frequency and peak-to-peak change in transpulmonary pressure were greater in Belgian white and blue cattle than in Friesian cattle. In the former, tidal volume, specific tidal volume, lowest transpulmonary pressure during expiration, transpulmonary pressure at the functional residual capacity level, dynamic lung compliance and oxygen tension in arterial blood were smaller. Airflow, minute volume and carbon dioxide tension in arterial blood were similar in the Belgian white and blue and Friesian cattle. These results were related to the great sensitivity of double-muscled cattle of the Belgian white and blue breed to laryngitis and bronchopneumonia

Selective blockade of NF-kappaB activity in airway immune cells inhibits the effector phase of experimental asthma

peer reviewedaudience: researcher, professiona