Zootechnical glossary

Yield

Amount of milk per milking/day/lactation. Lactation peak is 60–90 days after calving; the curve drops toward dry-off.

Lactation

Milk production period after calving — standard 305 days. Service period (calving→conception) affects length.

Dry period

60 days without milking before calving — udder recovery and lactation prep. Skipping it = udder disease.

Culling

Removing animals from the herd: disease, low yield, age, reproductive problems. Norm 20–30%/yr in a dairy herd.

SCC (somatic cells)

Udder-health indicator in milk: >200k/mL = subclinical mastitis, >400k clinical. Affects milk price.

Feed conversion

Kg feed per kg gain/L milk: broilers 1.5–1.7, pigs 2.6–3.2, beef cattle 6–8. A key economic metric.

Milk replacer (MRS)

Whole-milk replacer — powder for feeding youngstock; cheaper than whole milk at good composition.

Service period

Days from calving to successful conception. Optimum 80–110; >150 — reproductive problems, yield loss.

Dressing percentage

Carcass share of live weight: cattle 50–60%, pigs 70–75%, broilers 70–72%. Meat-productivity indicator.

Tallow / by-product feeds

Fat supplements and by-products (DDGS, pulp) in rations — cheaper energy but need balancing.