(a) Describe the Van Soest method of forage fiber analysis. 10 (b) Describe the different methods for study of heart sounds in…

(a) Van Soest method of forage fibre analysis

Van Soest (1960s) replaced the Weende crude-fibre method, which loses part of the lignin and hemicellulose, with detergent extraction that separates cell contents from cell wall. Samples are extracted by boiling with detergent solutions and the residue is weighed after filtering, drying and ashing.

Neutral detergent fibre (NDF): boiling in neutral detergent (sodium lauryl sulphate, EDTA, sodium borate, disodium phosphate, triethylene glycol, with amylase and sodium sulphite for starchy feeds) dissolves cell contents (sugars, starch, protein, pectin), leaving the cell wall: hemicellulose, cellulose, lignin and some silica.

Acid detergent fibre (ADF): a separate sample boiled in acid detergent (cetyltrimethylammonium bromide in 1 N sulphuric acid) dissolves hemicellulose and most protein, leaving cellulose, lignin and silica.

Acid detergent lignin (ADL): ADF treated with 72% sulphuric acid removes cellulose, and the residue is lignin plus ash; ashing gives ADF and ADL on an ash-free basis.

By difference: hemicellulose = NDF − ADF; cellulose = ADF − ADL; cell contents = 100 − NDF. NDF is negatively related to intake and ADF to digestibility, so both are used to predict forage quality.

(b) Methods for the study of heart sounds in animals

Auscultation is the basic method, direct (ear on chest) or indirect with a stethoscope in a quiet place, with the animal standing. On the left side the mitral area lies at the fifth intercostal space, the aortic at the fourth, below the shoulder line, and the pulmonic at the third; the tricuspid area is on the right side at the third to fourth space. Normal sounds are S1 (closure of atrioventricular valves, start of systole) and S2 (closure of semilunar valves); S3 and S4, related to ventricular filling and atrial contraction, are often heard in healthy horses and cattle. Rate, rhythm, intensity and murmurs are assessed.

Palpation detects precordial thrill. Phonocardiography records heart sounds and murmurs as a graph, often with an electrocardiogram, to time them in the cardiac cycle. Electronic and digital stethoscopes amplify and record sounds. Echocardiography (M-mode, two-dimensional) and Doppler studies show valves, chamber size and blood-flow jets, and identify the cause of murmurs.

(c) Economic considerations in commercial dairy farming

Capital and fixed costs: land, buildings, equipment (milking, cooling) and animals, with depreciation, interest and insurance on them. Variable costs: feed and fodder (about 60–70% of the cost of milk), labour, veterinary care, breeding, electricity and transport.

Returns: milk (the main item, priced by fat and SNF), calves, manure and culled animals; subsidies and credit through NABARD and schemes such as the Dairy Entrepreneurship Development Scheme.

Decision factors: breed and lactation yield, calving interval and herd structure (proportion of milch animals), cost per litre against price, scale of operation, marketing through cooperatives or private buyers, and risk from disease, price and feed. Indicators: cost per litre, net income per animal, benefit–cost ratio and break-even yield. Profit depends on cheap, quality feed, good breeding and health management, and reliable milk marketing.

(d) Sire indices for assessing breeding worth of bulls

A sire index estimates a bull's breeding value from the performance of his daughters, so it is a progeny test. Main indices:

• Simple daughter average: mean of daughters' records, ignoring dams and environment.
• Daughter–dam comparison: daughter average minus dam average; it corrects for the genetic level of dams.
• Equiparent index: 2 × daughter average − dam average (Robertson and Rendel), which adds the expected gain of daughters over dams.
• Herdmate or contemporary comparison: daughter average minus the average of daughters of other sires in the same herd and season, which removes environmental effects.
• Bayesian or regressed index, which shrinks the daughter mean according to the number of daughters and heritability, with a weight b = 2n h²/(4 + (n − 1)h²).
• BLUP (best linear unbiased prediction), the modern standard, which uses all relatives' records with herd and year effects and gives breeding values with reliability; it is now being extended to genomic selection.

(e) National Livestock Mission (NLM)

NLM, a centrally sponsored scheme started in 2014–15 and restructured in 2021–22, aims at sustainable livestock development, better productivity and income for small farmers. Its components are:

• Sub-Mission on Breed Development of Livestock and Poultry: support for breeding farms and improvement of sheep, goat, pig, poultry and other species.
• Sub-Mission on Feed and Fodder Development: fodder seed production, silage and fodder-block making, and conservation of pasture land.
• Sub-Mission on Innovation and Extension: skill training, technology transfer and innovation.
• Entrepreneurship Development: 50% capital subsidy for poultry, sheep, goat and pig enterprises and fodder units, with livestock insurance.

The mission is directed at small and marginal farmers, women and rural youth.