Arthropathy associated with Brucella abortus strain 19 vaccination in cattle. I. Examination of field cases

Thirty cows presenting with lameness and persistent serological reactions to Brucella abortus had chronic granulomatous arthropathy of the femorotibial and occasionally other joints. Attempts to culture Brucella or other pathogens gave negative results but organisms of Brucella morphology were seen in fluorescent antibody-stained cryostat sections of synovial tissue. The synovial fluids contained high titres of antibodies to B. abortus and Yersinia enterocolitica O:9 and had elevated total protein and immunoglobulin concentrations showing an oligoclonal electrophoretic profile. Immune complexes and rheumatoid factor were detected in some of the fluids.     

Effect of fast freezing then thaw‐aging on meat quality attributes of lamb M. longissimus lumborum

The objective of this study was to determine the effect of two different freezing rate then thaw‐aging regimens on the quality attributes of lamb loins. The loins were randomly allocated to one of five different freezing/thawing/aging regimes: fast‐(FF1A0) and slow‐(SF1A0) frozen only; fast‐(FF1A2) and slow‐(SF1A2) frozen then thaw‐aged for 14 days; aged for 14 days never frozen (A2). FF1A2 samples had a significantly higher water‐holding capacity compared to the slow frozen regardless of further aging periods. FF1A2 samples had lower (p < 0.05) shear force values than A2 and higher (p < 0.05) water‐holding capacity compared to the SF1A2. Fast freezing resulted in more intracellular cryo‐damage, whereas slow freezing resulted in extracellular cryo‐damage. FF1A0 and SF1A0 samples had lower (p < 0.05) myofibrillar proteins degradation. This study demonstrated that fast freezing then thaw‐aging can result in an improved water‐holding capacity and tenderness through the minimization of extracellular ice crystal formation, reduction in purge and drip losses, and improved proteolysis in thawed lamb.     

Effects of electrical stimulation and pre‐rigor conditioning temperature on aging potential of hot‐boned beef M. longissimus lumborum

The objective of this study was to create various pH/temp decline rates in hot‐boned bull beef M. longissimus lumborum (LL) through a combination of electrical stimulation (ES) and pre‐rigor holding temperature. The relationship between the pre‐rigor interventions, the activities of µ‐calpain and small heat shock proteins (sHSP), and the impacts on meat product quality were determined. Paired LL loins from 13 bulls were hot‐boned within 40 min of slaughter, immediately ES and subjected to various holding temperatures (5, 15, 25, and 35°C) for 3 hr. The rate of muscle pH decline, sarcomere length, shear force, and proteolysis of muscle proteins were measured. ES‐25°C had a longer sarcomere length compared to non‐electrical stimulation samples. ES‐25°C and ES‐35°C samples had lower shear force values, higher µ‐calpain activity and higher desmin, troponin‐T, and sHSP degradation. The above findings suggest that pH/temp decline rates created in hot‐boned muscle impacted muscle protein proteolysis by increasing the activity of proteases and degradation of sHSP.     

Sperm mitochondrial regulation in motility and fertility in horses

The biological nature of age‐related declines in fertility in males of any species, including stallions, has been elusive. In horses, the economic costs to the breeding industry are frequently extensive. Mitochondrial function in ejaculated sperm, which is essential for sperm motility, is reflected by adenosine triphosphate production, mitochondrial oxidative efficiency and production of reactive oxygen species, and that this balance may become compromised in ageing stallions and during the process of cryopreservation. This presentation will focus on mitochondrial integrity and function as an avenue for understanding the pathophysiology of sperm when undergoing cryopreservation and male ageing. We discuss the importance of understanding the differences and similarities of sperm mitochondria to that of somatic cells regarding structure and mitochondrial biochemistry relating to sperm function. The roles of oxidative phosphorylation and glycolysis in sperm mitochondria are outlined as is the method of determining oxygen consumption and calcium homoeostasis in sperm mitochondria. Further, we outline the role of oxidative stress and reactive oxygen species.     

Cardiopulmonary effects and recovery characteristics of horses anesthetized with xylazine–ketamine with midazolam or propofol

Objective

To evaluate cardiopulmonary and recovery characteristics of horses administered total intravenous anesthesia (TIVA) with xylazine and ketamine combined with midazolam or propofol.