(a) Describe the significance, composition and physical forms of creep feed in piglet. 15 (b) Describe the different types of…

(a) Significance, composition and physical forms of creep feed in piglets

Creep feed is a palatable, nutrient-dense diet offered to suckling piglets from about 7–10 days of age until weaning, in a creep area the sow cannot enter.

Significance: sow milk yield falls after the third week, and creep feed fills the gap, raises weaning weight and reduces pre-weaning loss. It also stimulates early secretion of amylase and proteases and gut development, so piglets meet solid feed before weaning and the post-weaning growth check and diarrhoea are reduced.

Composition: 18–22% crude protein with balanced amino acids, lysine about 1.4–1.6%; digestible energy from cooked or flaked cereals (maize, oats); 10–20% milk products (dried whey, skim milk powder) for lactose; spray-dried plasma, fish meal or soya protein concentrate; vitamins, trace minerals (iron, zinc, copper) and acidifiers to lower gut pH.

Physical forms: mash is cheap but wasteful and dusty. Pellets (2–3 mm) reduce selective eating and wastage and increase intake. Crumbles, made by breaking pellets, suit the youngest piglets. Gruel or liquid feed, mixed with warm water or milk replacer, encourages early intake but needs clean feeders to prevent spoilage.

(b) Types of hypoxia in animals

Hypoxia is a deficiency of oxygen at tissue level, and it is classified by cause into four types.

Hypoxic hypoxia: arterial PO₂ and haemoglobin saturation fall. Causes are high altitude (brisket disease in cattle), airway obstruction, hypoventilation and impaired alveolar diffusion as in pulmonary oedema or emphysema.

Anaemic hypoxia: PO₂ is normal but oxygen-carrying capacity falls. Causes are haemorrhage, heavy Haemonchus contortus infection in sheep, carbon monoxide (carboxyhaemoglobin) and nitrate or nitrite poisoning in ruminants, which forms methaemoglobin.

Stagnant (circulatory) hypoxia: PO₂ and haemoglobin are normal but blood flow is slow or inadequate, as in heart failure, shock, or vascular occlusion such as aortic thromboembolism.

Histotoxic hypoxia: oxygen is delivered but cells cannot use it because oxidative enzymes are blocked. Cyanide poisoning from young sorghum or other prussic-acid-yielding plants inhibits cytochrome oxidase, and the venous blood stays bright red.

Signs are general: rapid breathing, cyanosis (absent in histotoxic and carbon monoxide hypoxia), weakness and collapse.

(c) Methods for assessment of postnatal growth in animals

Body weight: weighing at fixed intervals on the same scale and at the same time of day, preferably before feeding, gives average daily gain (ΔW/Δt), and relative growth rate (ln W₂ − ln W₁)/(t₂ − t₁) × 100.

Linear and girth measurements: height at withers, body length, rump width and chest depth (measuring stick or tape) follow skeletal growth. Heart girth is the most useful; in cattle, weight (lb) is estimated by Schaeffer's formula: heart girth² × length ÷ 660 (inches).

Body condition score: palpation and visual scoring of fat cover (1–5 in cattle and small ruminants), independent of frame size.

Growth curves: weight against age is plotted and fitted with Gompertz, Brody or logistic models, whose parameters (asymptotic weight, rate of maturing, inflection point) are compared with breed standards. Huxley's allometric equation Y = aXᵇ describes the growth of parts relative to the body.

Feed efficiency: feed conversion ratio (feed ÷ gain) and residual feed intake.

Modern tools: real-time ultrasound measures eye-muscle area and back-fat, and imaging, DEXA and body-composition methods, such as deuterium dilution, measure tissue growth. Measurement must be standardised and compared within the same sex, breed and age group.