The measurements of hoof were carried out on 46 adult dairy cows of the institutional dairy farm located at Bengaluru and Shivamogga. The age of the animals was determined by the dental formula. The following linear measurements (Fig 1) were taken in centimeter (cm) using a flexible measuring tape as previously described by
Scott et al., (1999). Accordingly, the measurements taken were; coronary band (the distance around the proximal border of the coronary band from the abaxial groove to flexure of the dorsal surface), base (the distance from the abaxial groove, along the distal border or weight-bearing region of the hoof to the point of the toe), abaxial groove (the height of the abaxial groove from the proximal border of the coronary band to the base of the hoof) and toe (the length of the toe from the proximal border of the coronary band to the point of the toe).
For assessment of hoof volume, three measurements (coronary band, base and abaxial) were taken from medial (left and right) and lateral (left and right) claws of forelimb and hind limb in centimeters. The measurements of lateral and medial claws of the same hoof were added and the values were put in the following formula
(Scott et al., 1999):
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Claw volume (cm3) = (17.192 x Base) + (7.467 AbaxGr) + 45.270 x (CorBand) -798.5
For the measurement of the thickness of the hoof capsule, the hoof samples of dairy animals were collected from post mortem cases from animals which had died not due to hoof lesions. Samples were brought to the laboratory and washed and cut mid-sagitally and were measured for the thickness of hoof capsule (mm) using caliper at different points on the wall (a, b, c) and on solar surface (d, e and f) as shown in the Fig 2.
Evaluation of a lameness scoring system for dairy animals
The evaluation for the cow for lameness was done before and after the application of Cowslips onto the animals. Locomotion Score is a qualitative index of a cows’ ability to walk normally. Visually scored on a scale of 1 to 5 (Table 1), where a score of 1 reflects a cow that walks normally and a score of 5 reflects a cow that is three-legged lame, an LS is visually assessed in only a few seconds per cow.
A 5-point lameness scoring system was developed based on previously published systems but optimized for use under field conditions. The scoring system included the words “in most cases” in the descriptions of the clinical signs evaluated. This was done to avoid a situation in which cows might not fit into any of the categories. Additionally, a number of clinical signs used in other lameness scoring systems, considered of less importance in relation to lameness, were not included. Only clinical signs were included that could easily be assessed within a few seconds from a distance
(Thomsen et al., 2008).
Anatomical terms were used in agreement with the Nomina Anatomica Veterinaria (NAV, 2005). The photographs of hoof samples were taken using a digital camera (Nikon®, MH 611 COOLPIX P5100, Japan).
Histology of the of hoof capsule
To study the microscopic structure of the hoof capsule, a tissue of 5-10 mm thickness was collected from the hooves of six crossbred cows (blue rectangle in Fig 3), fixed in 10% neutral buffer formalin and processed for routine histological technique with some modifications. As some samples contained keratin, we used harsh hydration process, which consisted of treatment with 10% HCl for 15-30 min and then put it on ice. The tissue pieces were routinely processed and embedded in paraffin wax (Luna, 1968). Then, the samples were sectioned using semi-automatic microtome (Leica® RM2245, Leica Biosystems Pvt. Ltd., Singapore) to make 5-7 µm thickness sections, the sections were carried on glass slides which were smeared with a swab of Mayer’s egg albumin and then placed on the hot plate for 24 hours for the purpose of drying. The slides were stained using routine H and E staining technique (Singh and Sulochana, 1996). The photographs were taken with a Nikon digital camera (Nikon®, MH 611 COOLPIX P5100, Japan) attached to CH 20i Olympus trinocular microscope. For image analysis, slides were viewed in a microscope (Olympus CX 41) equipped with a Q-imaging Micro publisher 3.3 RTV. The image was reflected onto the screen of a Q-Capture Pro 7 for measurements.
Designing and development of rubberized cowslips
Based on the literature survey and considering the physical properties of the available materials and their usefulness in the preparation of Cowslips, rubber material was selected to prepare Cowslips. The designing of rubberized Cowslips was carried out manually as per the cobbler’s procedure based on morphometric data obtained in the present study in the laboratory of MyPol, Pvt Ltd, Mysore (Fig 5).
The rubberized Cowslips were prepared manually using the above hoof cast prepared in the laboratory of MyPol Pvt Ltd., Mysore. The waste tyres were collected from automobiles shops and they were cut to the required sizes and shape. The size and shape of Cowslips were optimized for perfect design and prepared at three different sizes
viz., small, medium and large. Initially blueprint for hoof was designed, followed by the blueprint for hoof and then card/drawing sheet template and then the negative molds (hoof cast) for the different sizes of hoof were prepared using thermostable materials. Below this mold, the lower hard part of Cowslips was designed using 0.5 to 1cm thick pieces of rubber wastes. Over the mold, the upper soft part of Cowslip comprised of nylon cloth which was glued to the lower part to get perfect shape and size of Cowslips. Finally, the whole set up along with mold was vulcanized as per standard process to get durable Cowslips (Fig 5).
Application of the cowslips to the hoof of animals
A randomized trial on the application of Cowslips was conducted at Institutional farm located at the veterinary college campus, Shivamogga, Karnataka, India. The claw of the hoof on which the Cowslip is to be applied was selected. It was ensured that there were no lesions on the claw on which Cowslip was to be applied.
To ensure proper adhesion of the Cowslip, it is essential that the claw of the hoof should be prepared. Then the conditioner (comprising a mild acid, ferric chloride) was applied to the selected claw of hoof for a time sufficient to etch and further expose the epidermis layer of the hoof until stratum externa approximately 1-2 mm depth (Lustgarten, 2007). The claw was dried thoroughly with a paper towel and wiped with spirit to degrease it. Then, the Cowslip was tested to make sure that it fitted to claw. Cyanoacrylate based instant adhesive (Anabond® 202) was applied to the interior of the Cowslip profusely. The Cowslip was applied to the claw applying gentle pressure on the wall of the hoof and the excess adhesive was cleaned. Leave the foot off the ground until the glue is dry. Then the cow was allowed to still stand for a few minutes (Fig 5). Finally, the observations were recorded to evaluate the retention period of the Cowslips as shown in Table 2. For comparison, Demotec® (UK, Distribution, Centre, Shropshire) Cowslips imported were also applied on to hoof of normal animals (n=8) as per manufacturer’s instructions and the retention period was recorded.
Additionally, to study the effect of urine on adhesiveness of the cyanoacrylates between hoof and rubberized Cowslips, the Cowslips were applied onto the hooves of animals collected from post-mortem samples using cyanoacrylates based instant adhesive (Anabond®, 202) and then kept them in jar containing undiluted cow urine and tap water for 30 days to observe for the bondability of adhesives in the urine by checking the firmness of attachment subjectively.
Statistical analysis
The statistical analyses of various biometrical parameters of hoof were depicted in a tabular form (Table 2). Data were presented as Mean ± SEM. The nomenclature used was referred to according to the International Committee on Veterinary Gross Anatomical Nomenclature (2005).