Background: Upward fixation of patella is common clinical malady in cattle due to extensive movement of stifle joint during the locomotory activity because of unknown etiology. However, at certain peak point (overstretching of ligament) or due to occupational trauma (wear and tear), ligament become flaccid and weak leading to patellar displacement and lameness. Patellar ligaments play crucial role in stifle joint movement and any functional or structural alterations in the ligaments can lead to acute to chronic lameness in cattle. The present study was carried out to evaluate the structural changes in collagen fibril material in medial patellar ligament in cattle suffering 
with patellar luxation.&nbsp;&nbsp; 
 
Methods: Tissue specimens of medial patellar ligament of normal (control animal) and affected cattle (luxation of patella) were harvested and preserved for scanning electron microscopy (SEM) and transmission electron microscopic (TEM) study as per standard procedure at RUSKA Laboratories, College of Veterinary Science, PVNRTVU, Rajendranagar, Hyderabad, India. 
 
Result: The incidence of medial patellar luxation was higher in females as compared to male cattle and the duration of lameness was between 3-12 months (7.35&plusmn;0.56 months) characterized by dragging of toe, outward jerky movement of affected limb, extension of limb and change in appearance of gait during walk and flexion of fetlock. Scanning electron study of normal ligament showed dense, uniformly and compact arrangement of collagen fiber bundles with morphometric thickness was 3.66&plusmn;0.58 &micro;m. whereas in luxated patella cases, medial ligament showed derangement in collagen fiber bundles. The collagen fibers were arranged irregular and wavy with morphometric thickness of collagen was 2.58&plusmn;0.03 &micro;m. Electron microscopy of the normal ligament showed presence of thick collagen fiber bundles packed in dense and compact arrangement. Electron microscopy of affected ligament had degenerative changes of the fibers characterized by thin collagen fiber bundles which were loosely and disorganized arranged fibrils. The present study concludes that, luxation of patella was common locomotory disorders in cattle due to derangement in collagen fiber bundles with drastic reduction in thickness of collagen fibers, increased gap between two collagen fibers, broken and overlapping fiber bundles and surface of collagen fibers appeared irregular rough via scanning and electron microscopy analysis.

Collagen Fibril Morphological Study of Medial Patellar Ligament of Stifle Joint Affected with Patellar Luxation in Cattle

<div>Background: Cardiac disorders are the second most common disorders after cancer in dogs. Cardiac disorders are often fatal and/or silent killers in canines. In our country, in the majority of cardiovascular disorders, there is a frequent omission by clinician and client due to lack of awareness. However, any cardiac abnormality requires to be dealt with top priority to avoid morbidity and mortality in the dog population. The present study was aimed to know the electrocardiographic interpretations of cardiac disorders in dogs. 
 
Methods: For this purpose, a total of 5110 dogs presented at Veterinary Clinical Complex, College of Veterinary Science and Animal Husbandry, Nanaji Deshmukh Veterinary Science University, Jabalpur, Madhya Pradesh, from November 2019 to June 2020 were screened. Among them, 137 dogs had clinical signs about cardiac disorders were subjected to thorough electrocardiographic recordings for interpretations of various cardiac conduction anomalies. 
 
Result: Electrocardiography revealed various types of supraventricular and ventricular abnormalities. Among supraventricular disorders maximally wandering pacemaker (30.60%) was recorded followed by atrial fibrillation (22.58%), left atrial enlargement (8.06%) and sinus arrest (4.84%) in dogs. Among ventricular abnormalities; left ventricular enlargement, right ventricular enlargement and biventricular enlargement (i.e. 41.67%, 37.49% and 8.33%, respectively) were commonly diagnosed.</div>

Electrocardiographic Interpretations of Cardiac Disorders in Dogs

Extracellular matrix (ECM) is the major macromolecule in skeletal muscle, and collagen is main component of ECM surrounding muscle fiber and adipocyte, which affect meat quality greatly. The remodeling of ECM is regulated by matrix metalloproteinases, such as ADAMTS2, which is essential for the maturation of triple helical collagen fibrils in body. The expression patterns of COL1A1, COL2A1, COL3A1 and ADAMTS2 in longissimus dorsi muscle were explored by qRT-PCR and results indicated that the expression levels of COL1A1, COL3A1 and ADAMTS2 were significantly higher at 3 and 24 month, while significantly lower at 12 and 30 month. The expression of ADAMTS2 and COL1A1 had significant positive relationships with intramuscular fat content, while expression of COL3A1 had significant positive relationship with shearing force and water holding capacity in cattle. The expression levels of collagen and ADAMTS2 were significantly higher in mesenteric fat, mammary fat pad and subcutaneous fat than in longissimus dorsi muscle, biceps femoris and infraspinitus tissues. The expressions levels of COL1A1, COL3A1 and ADAMTS2 were significantly lower in marbling fat than in other fat tissues. This study indicated that the expression of collagen and ADAMTS2 had important effects on postnatal skeletal muscle development and meat quality.

Collagen Fibril Morphological Study of Medial Patellar Ligament of Stifle Joint Affected with Patellar Luxation in Cattle

Electrocardiographic Interpretations of Cardiac Disorders in Dogs

The relationships of collagen and ADAMTS2 expression levels with meat quality traits in cattle