Dairy Farming Glossary

The rate of weight gain per day in growing cattle, measured in lbs/day or kg/day. Target ADG for feeders is 1.5–2.5 lbs/day.

The absence of estrus cycles. Cows fail to show heat. Common in early lactation, first-calf heifers, and energy-deficient cows. A leading cause of reproductive failure.

A metabolic condition caused by excessive rumen acid production (low pH). Subacute (SARA) is common in high-producing dairy cows fed high-concentrate rations. Reduces fiber digestion and milk fat.

The deliberate introduction of semen into the female reproductive tract to achieve pregnancy. Used in 90%+ of US dairy cows. Enables genetic improvement and disease control.

A 1–9 visual scoring system assessing fat cover over the spine, ribs, and tail head of cattle. BCS 5 is ideal for most beef cows.

Protein that escapes rumen degradation and is absorbed in the small intestine. Essential for high-producing cows. Sources: heat-treated soybean meal, fish meal, distillers grains.

The first milk produced after calving, rich in antibodies (immunoglobulins) essential for calf immunity. Calves must receive it within 6 hours of birth.

The percentage of the herd removed annually. Average is 25–35%. Includes voluntary (low production) and involuntary (health, reproductive failure) culling.

Energy-dense, low-fiber feeds (grains, byproducts) added to forage-based rations to boost energy and protein. Typically 30–60% of the dairy ration.

The number of days between two consecutive calvings. Target: 12–13 months (365–400 days). Longer intervals reduce lifetime milk production.

Diarrhea in calves under 30 days old. The leading cause of calf mortality, accounting for 50–60% of pre-weaning deaths. Causes: viruses, bacteria, parasites.

A mandatory non-lactation period of 45–60 days before calving, allowing the udder to rest, regenerate tissue, and prepare for the next lactation.

The amount of feed consumed excluding water content. Expressed as a percentage of body weight: lactating cows 3.0–3.5%, dry cows 1.8–2.0%.

The number of days since calving. Used to track lactation stage, manage nutrition, and make breeding decisions. Peak at 20–60 DIM, breed at 50–80 DIM.

When the abomasum (true stomach) shifts to the left or right side of the abdomen. Usually occurs in the first 2 weeks after calving. Requires surgery.

The period in the reproductive cycle when a female cow is receptive to mating. Also called "heat," it typically lasts 12–18 hours.

The ratio of feed consumed to weight gained. Lower is better. Feedlot cattle: 6–8 lbs feed per lb of gain. Dairy: 0.7–0.9 lbs DMI per lb of milk.

Plant material (grass, legumes, crop residues) used as feed. The foundation of ruminant nutrition. Provides fiber for rumen function and energy for production.

The period from conception to calving. Average 283 days for dairy cattle (278–290 days by breed) and 310 days for buffalo.

Revenue per cow minus feed cost per cow. The gold standard KPI for dairy profitability. Higher IOFC = more profitable herd.

A metabolic disorder caused by negative energy balance, resulting in elevated ketone bodies. Common in early lactation (3–14 DIM). Reduces milk and fertility.

The period of milk production following calving, typically lasting 305 days in dairy cows. Peak production occurs at 4–8 weeks post-calving.

Abnormal gait or posture due to foot or leg problems. Affects 20–30% of dairy cows. Reduces milk production by 10–15% and impairs fertility.

Inflammation of the udder tissue, typically caused by bacterial infection. The most costly disease in dairy farming, accounting for 35–40% of vet costs.

A metabolic disorder caused by low blood calcium at calving. Affects 5–8% of dairy cows. Can be fatal if untreated. Prevention via low-calcium pre-fresh diets.

A hormone produced by the corpus luteum (CL) on the ovary. It maintains pregnancy and prepares the uterus for embryo implantation. Tested via milk or blood.

The percentage of eligible cows that become pregnant per estrus cycle. Calculated as Heat Detection Rate × Conception Rate. Target: >25% per 21-day cycle.

The process of regurgitating, re-chewing, re-salivating, and re-swallowing feed. Cows ruminate 6–8 hours per day, producing 100–150 liters of saliva daily.

Failure to expel the fetal membranes within 12 hours of calving. Affects 5–10% of dairy cows. Increases risk of metritis and reduces fertility.

The total milk revenue per 100 lbs (hundredweight) of milk sold. Includes base price plus/component premiums minus quality penalties. A key pricing metric for dairy profitability.

A measure of white blood cells in milk, used as an indicator of udder health and mastitis. Normal is <200,000 cells/mL; >400,000 triggers penalties.

The number of animal units (AU) per acre of pasture. A stocking rate of 1 AU/acre means one 1,000 lb cow per acre. Balances forage availability with animal demand.

A blend of forages, concentrates, minerals, and vitamins mixed into a single uniform ration. Ensures every bite is nutritionally balanced.

A composite measure of heat stress combining temperature and humidity. THI >68 triggers heat stress in dairy cows. THI >80 is severe — milk production drops 10–35%.

The period after calving during which a farmer deliberately chooses not to breed the cow. Typically 50–80 days. Allows recovery before rebreeding.