Feet Leg and Bone Beef Cattle

Structure AND Lameness

by Alex Ashwood

BRAHMAN NEWS MARCH 2011 Effect #170

Today's beef producers face many unlike management challenges including increased herd sizes and larger cattle which impact on herd health particularly leg and feet structure and lameness.

Lameness has a positive genetic correlation to reduced performance

Foot and leg problems can be a major herd problem due to reduced operation (weight gain and reproduction) resulting in lower productivity and increased economic losses.

Figure i illustrates the four main groups of factors which can directly atomic number 82 to lameness or which collaborate and subsequently intensify minor stimuli sufficiently to cause subacute or acute lameness.

FIGURE one: PREDISPOSING CAUSES OF LAMENESS

Nutrition, environment, disease and genetic influences combine with management factors to predispose stock to lameness.

Foot and leg conformation have less predictable heritability (0.8-0.16) than the measurable functioning traits (eg mature weight 0.50). Nevertheless, structural traits and problems are heritable and demand to exist fully considered when purchasing and breeding seed stock.

"Foot issues compounded by poor leg structure cause lameness"

In gild to fully understand lameness it is advantageous to become familiar with the anatomy of the human foot and the basic structure of the legs, shoulder and hindquarter.

Pes Structure

The conformation of the foot (Figure 2) should exist short and steeply angled, high in the heel and even clawed. The sole should be somewhat concave with the majority of weight placed on the hoof wall.

Figure 2: cross section of the foot

Source : Zinpro®

Effigy 3: EXAMPLES OF FOOT DEFECTS

The anatomy of the foot (Figure ii) indicates the complexity of the construction and clearly demonstrates why structural faults and bug lead to foot damage and lameness.

• Coronary Band – is normally soft and shiny and grows at the rate of v millimetres per month. This is an area that can be easily penetrated by foreign objects particularly betwixt the toes
• Bulb – is the continuous with the coronary ring and is composed of soft safe horn.
• Wall – is polish and shiny and consists of a very tough tubular horn
• Coronary Absorber – is a mass of elastic tissue and veins beneath the coronary ring. When the fauna moves, the cushion pumps claret through the foot and back into the body.
• Lamellae – there are hundreds of tiny ridges in the lower office of the inside wall which are fastened by fibres to the bury bone.
• Periople – is the area where the pare meets the coronary band. It is here that lamitis is frequently first noticed.
• Corium – sometimes called the 'guide or dermis" produces hoof horn (wall). The health of the corium establishes the quality of the hoof produced. Reduced quality leads to foot harm and lameness. Extreme concussion to the corium due to poor leg structure creates sensitivity, pain and lameness.
• Coffin Bone – sometimes called the pedal os is suspended within the corium and when damaged or stressed causes astringent lameness.
• White Line – is a greyish area where the sole meets the hoof. Its function is to separate sensitive tissue from non sensitive tissue. Information technology is an surface area that can exist hands penetrated past foreign objects, peculiarly with faulty pes structure
• Digital Cushion – is situated inside the bulb and functions as an elastic shock cushion. It likewise forces blood back into the limbs as the creature walks.
• Pes defects (eg scissor and corkscrew claws) are genetic (inherited) and overgrown anxiety is mostly a sign of poor leg construction and/or nutritional bug.

Foot Angle and Depth

Studies show that higher claw angles are positively correlated with increased herd life of bulls. The ideal bending is about 45-55 degrees. Difference from this bending normally indicates poor leg structure (eg sickle or direct hocks and weak pasterns).

Defective feet generally worsen with age and problems are accentuated with poor feed direction (eg overfeeding grain and insufficient minerals) and challenging environments (too abrasive or wet).

Heel depth is related to foot angle and deeper heels with sufficient angle reduce the incidence of lameness. Heel depth is also related to the gradient of the pastern (Figure iv).

Effigy four: Human foot AND PASTERN Construction

Long slopping claws or brusk cake claws signal likewise much or not enough pastern bending and can indicate structural faults of the pastern or the upper limbs (eg shoulder also straight). Incorrect angle of the pastern causes the hoof to habiliment abnormally which affects the mobility and operation of the brute. Shallow heels can lead to bruising and increase the chances of damage and infection.

Weight Distribution

While standing the weight should exist distributed between the front and hind legs.

"Most lameness (85 per cent) involves the hind feet"

A elementary calculation will signal how much weight is carried and clearly demonstrates why the foot can be easily stressed. With a 460 kg heifer, approximately 260 kg rest on the forelegs and 200 kg on the hind limbs (Figure v). This means a weight of 100 kg per hind leg or 50 kg per claw (Figure 5). Note: this means that substantial pressure is placed on a few square centimetres of the corium under the pedal bone.

With heavier animals (eg bulls) twice as much weight tin can be transferred to the foot and hooves (eg a mature bull tin transfer 200 kg per hind leg and 100 kg per claw). When servicing a moo-cow these weights are increased even further. Subsequently sensitivities in hind legs and feet reduces reproduction.

During locomotion, the centre of gravity ("Thousand") shifts from side to side (Effigy 5) and the weight bearing past each hind claw varies with the move.

FIGURE 5: WEIGHT DISTRIBUTION ON THE FOOT

"The majority of hind leg lameness involves the outside hook"

The outside hook of the hind legs behave the burden of the continuously changing weight load during locomotion. This may exist the reason that these claws are more often damaged.

The outer hind claw is more heavily stressed which explains why the outside claw is larger than the inside claw and the heel is deeper and the sole thicker. Despite these adaptations the results of poor leg structure leads to an increased incidence of lameness.

The front anxiety bear weight load changes more evenly but when problems practise occur the inside claw is commonly the virtually afflicted.

Damaged Feet

The foot is protected by the hoof and its outer structures (Figure 2). The hooves are the get-go line of defence against foreign objects and infection. Foot harm can too exist caused by internal factors such as poor feed management and illness (Figure 1).

Leg Construction

Abnormal structure of the hindquarter, shoulders and legs alters weight distribution, leading to stresses, inflammation and impaired function (ie walking and serving ability).

Structurally correct stock take a costless moving gait (locomotion) with the hind anxiety stepping into the front footprints. Over or understepping of the hind feet is an indication of structural leg issues.

"Structural problems increase the incidence of lameness"

- Forepart End

+ Shoulders

FIGURE vi: FRONT LEG AND SHOULDER Structure

The angle between the shoulder blade/shoulder/elbow should be xc-95o (Figure 6). Angles greater than this (eg directly shoulder) reduce shock absorption causing a short-choppy gait. With direct shoulder bulls the acme of the shoulder blade is prominent above the backbone and the stock have high-open shoulder blades instead of smooth shoulders against the ribs.

+ Front Legs

Figure seven shows that the legs should be straight when viewed from the front.

Effigy 7: Structure OF THE FRONT LEGS

With turned in knees (knock kneed) stock may have overgrown outside claws which contributes to stress and lameness. Turned in knees (bow legged) causes stock to roll their feet and these animals are prone to arthritis.

"Arthritis is acquired by poor leg and joint structures"

- The Rear End

+ Rear Legs

The bending between the hip and the hock joint should be 90-95o. Angles greater than this (postal service legged) reduces walking and mating ability.

Figure 8: SIDE VIEW OF FRONT AND HIND STRUCTURE

Notation: Correct front and hind structure is all most the angles betwixt the joints.

In that location is a strong relationship between rear leg structure and the soundness of the rear feet.

Figure ix shows the degree of inward (cow hocked) or outward (bow legged) divergence from the hocks. Normal limbs (a) facilitate directly locomotion with the bigger outer claw acquit the greater share of the weight load.

FIGURE nine: REAR VIEW OF HIND LEG STRUCTURE

Viewed from the back, the leg should be vertical. Stock with their hooves rotated outwards (cow hocked) can accept uneven growth of the outside claw. Stock that are wide at the hocks with their feet turned inwards (bow legged) tin can suffer increased levels of stress and strain on the ligaments causing lameness and permanent impairment.

"A high percentage of bulls are culled due to lost mobility"

Viewed from the side (Effigy x) straight hind legs (post legged) is a serious fault which leads to arthritis in the hocks, hips and joints.

Figure 10: SIDE VIEW OF HIND LEG STRUCTURE

Directly legged bulls are oft impuissant servers and can suffer high incidences of damage to the penis. Too much angle through the hocks (sickle hocked) whilst undesirable is not as serious a problem equally postal service leggedness. Sickle hocked bulls are also clumsy servers particularly at the dismount.

Both post leggedness and sickle hocked conditions adversely bear upon the bulls servicing chapters and lead to an earlier 'breakdown' in the life of the bull.

Nutrition

Feed direction will be discussed in a later on article titled "Acidiosis and Laminitis". Yet, incorrect energy and protein balances and mineral/vitamin deficiencies play a clear office in lameness.

All rations should be balanced for calcium, phosphorous for proficient os health. Other helpful minerals for foot health include zinc, copper, molybdenum and manganese.

Rations need to include the correct levels of fibre and the fibre should have the right physical form and particle size to increase chewing which produces saliva (buffer) which aids digestion.

Depending on the grain source, the not structural carbohydrates should not exceed 40 per cent of the ration. Feeding incorrectly processed grains with inadequate levels of fibre causes metabolic disorders and lameness.

"Arthritis is accentuated when young bulls are fed high grain rations"

Overfeeding protein can cause the abnormal growth of the hoof. Conversely lacking diets produce poor wall growth. Intensively feeding increases body weight subjecting joints, legs and anxiety to greater weight loads and stresses.

Disease

The nigh common bacterial cause of lameness is human foot rot. Foot rot is characterised by a necrotic lesion in between the claws (interdigital) which may extend into the soft tissues of the foot causing swelling and lameness. If not treated promptly and correctly, foot rot (and other foot diseases) can pose grave consequences for the infected animal.

"Mortalities may be low just mobility and economic loss is high"

Preventative measures include pes bathing (eg copper sulphate, Epsom salts) and treatment with injectable antibiotics equally prescribed your veterinarian.

Stock with poor leg/feet structure are more decumbent to foot injuries and infection.

Surroundings

The importance of environs should not be disregarded particularly for auction bulls held in small enclosures. Foot lesions vary in type and severity depending on the climate and the abrasiveness of the surfaces the animal walks on.

Hot, dry climates harden the hoof which may increment the resistance to trauma but causes the hoof to be more brittle. On the other mitt excessively moisture atmospheric condition soften the hoof and these weather condition favour invasion by leaner and foreign objects.

Choice Outcomes

Lameness and poor functioning due to structural faults is considered a major herd wellness problem which reduces herd performance. Only reproduction is more than important reason for selective culling. Furthermore, lameness and faulty leg/feet structure can accentuate reproduction bug.

Factors such as illness, unsuitable environments and poor feed management tin can play an interactive role in the incidence of lameness.

Genetic factors take a meaning role in lameness. Whilst heritabilities are depression (0.08-0.16) specific problems tin have medium (0.30) heritabilities.

Information technology is noted that several conformation traits have a strong correlation to lameness (Table 1). Heritabilities and genetic correlations between feet and leg conformation and herd life are shown in Tabular array ii.

Tabular array 1: GENETIC CORRELATION Betwixt LAMENESS AND Foot AND LEG STRUCTURE (SOURCE: ATKIN ET AL)

	Heritability	Genetic Correlation with
		Feet / Legs	Pes Angle	Rear Legs
Lameness	0.ten	+0.46	+0.59	+0.65

Tabular array 2: Pes AND LEG HERITABILITIES AND GENETIC CORRELATIONS WITH HERD LIFE (SOURCE: ATKINS ET AL)

Trait	Heritability	Genetic Correlation with Herd Life
Feet & Legs	0.21	+0.52
Foot Angle	0.13	+0.41
Heel Depth	0.10	+0.44
Bone Quality	0.28	+0.45
Rear Legs - side	0.26	-

Lesser Line

The genetic (inherited) component of minimising lameness can be significantly improved by selecting for desirable foot and leg conformation traits.

Breeders are subsequently urged to take special note of the leg and foot structure through visual assessment and performance data if available.

Ongoing, intense selection for structural correctness will substantially reduce the incidences of lameness and improve the overall performance of the herd.

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Source: http://www.brahman.com.au/technical_information/selection/structureAndLameness.html

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