Herd Illthrift

Herd Illthrift and Poor Performance (Growth, Milk Yield or Fertility) in Cattle

CAUSES OF ILLTHRIFT:

There are many causes of herd illthrift/poor performance/weight loss. MINERAL deficiency is NOT the most likely cause.

	MAJOR CAUSES	COMMENTS
1	Restricted water intake	Poor supply, contaminated water
2	Undernutrition	Poor grassland management (under or over-stocking); poor winter feeding; inadequate intake/quality of protein, energy; ketosis
3	Parasitism	Lungs (hoose); gut (Ostertagia, Nematodirus, Coccidia); liver (fluke); skin (mange, lice, ticks, keds, fly strike); brain (gid)
4	Infection	Current, or in early life, especially chronic infection: viral (influenza; BVD/Mucosal disease/IBR; rotavirus; Corona virus; parvovirus; adenovirus; orf); bacterial (Salmonella, Johne's disease, Listeria, Leptospira, Pasteurella, Haemophilus, TB, actinobacillosis, actinomycosis); protozoal (Coccidia, Cryptosporidia, Babesia, Eperythrozoon); mycoplasmal; fungal (Mucor, Aspergillus, ringworm, zygomycosis) etc
5	Severe mineral deficiency	P, Cu, Co, Se, I, and rarely Ca, Mg, Zn, Mn, Na
6	Severe vitamin deficiency	B12, thiamine (CCN), and rarely A, D3, E
	LESS COMMON CAUSES
7	Poisoning/intoxication (especially chronic)	Bacterial (E. coli, C. pyogenes etc); fungal (ergot, aflatoxin etc); plant (cottonseed (gossypol), brassica, acorn, cyanogenetic glucosides, alkaloids (especially ragwort), bracken, oxalate, fescue); ruminal lactic acidosis (grain, molasses poisoning); chemical (herbicides, fungicides, pesticides, side effect of antibiotic or therapeutic drugs (especially if over-dosed), ammonia/urea, nitrate, petroleum products, antifreeze, mineral compounds (As, Pb, F, Mg, Na, Cu, Co, Se, I, Zn, Mn); water toxicity etc); algal etc
8	Pain/inflammation	Lameness (foot rot, sole abscess, laminitis, arthritis, osteomyelitis, fractures, dislocations); pain / inflammation elsewhere (sore mouth / teeth / gum / tongue; pharyngeal lesions etc; pleuritis, peritonitis, reticulitis, endocarditis, pericarditis; mastitis, sinusitis, meningitis, encephalitis, castration, dehorning)
9	Internal disorders (especially lesions present from early life)	Lung (hoose, fog fever, abscess, infection, pneumonic lesions from early life); liver (abscess, liver disease); gastrointestinal tract (ruminal lactic acidosis, vagal indigestion, ruminal or omasal impaction; scour/gastroenteritis, winter dysentery, bloat, abomasal ulcer, bowel strangulation); kidney/bladder (inflammation, abscess, urolithiasis); abscess/sepsis (lungs, liver, kidneys, mastitis, peritonitis, pharyngeal injury)
	RARE CAUSES
10		Nutritional (deficiency of protein/energy, Cu, Co, Fe); parasitic (lice, fluke, worms etc); haemolytic (bacterial, protozoal, viral); aplastic / toxic (plant poisoning (kale, bracken etc); haemorrhagic (warfarin); immunomediated etc
11	Allergy	Lungs, gut, skin, immunomediated
12	Immunosuppression	Toxic, viral; neonatal agammaglobulinaemia (insufficient colostrum in neonates)
13	Genetics	Genetic defects, mannosidosis, poor genetic potential).
4	Fever	See infection, intoxication, allergy
15	Cancer	Lymphosarcoma, leucosis

REMEDIAL ACTIONS:

1. IDENTIFY AND CORRECT THE CAUSAL FACTORS (see above), especially poor water intake/quality and basic faults of nutrition, poor control of parasites and infection.

2. MINERAL SUPPLEMENTS?: If herd levels of P, Cu, Se, I or Co are low or very low on blood test, it is advisable to increase their supply.

A quick way to check if mineral deficiency is involved is to give a good mineral supplement high in trace-elements. See the enclosed notes on mineral supplements. If the animals do not show a good response within 3-6 weeks, the cause is unlikely to be mineral deficiency.

If minerals are only marginally deficient in blood, further supplementation with those minerals is unlikely to improve growth rate.

Author: Phil Rogers MRCVS Grange Research Centre, Dunsany, Co. Meath, Ireland 1997