Since 1990, the number of livestock in Mongolia has more than doubled. In large areas of Mongolia, grassland degradation is now a problem of national concern. A survey was done of 10 herders in two Soums (Altanbulag and Khashaat; heavily and moderately degraded, respectively) to measure the animals (sheep, goats, cattle and horse numbers, sex and weights) and grasslands (species and biomass) every 3 months from April 2017 to December 2018. Rainfall is mostly in summer and mean monthly temperatures vary from –20 to 208C. Throughout the study, the grassland herbage mass in summer was less than 0.5 t dry matter/ha, below that considered sustainable for the steppe. Herders had 200–1000 sheep equivalents (SE, 50 kg base weight), moved camps 2–4 times each year and stocking rates varied from 0.5–1 SE/ha. Female animals reached their mature weights by 4 years of age (sheep 50 kg, goats 40 kg, cattle 350 kg, horses 300 kg). Animals only grew over summer, but a significant part of that was compensatory gain in animals.1 year old. Over winter, sheep and goats lost 21–29% of their liveweight, cattle and horses 15–30%. The weaning rate was 43–48% across species. The male:female ratio (.2 years old) was sheep 63%, goats 72%, cattle 27% and horses 106%. All animals are managed in common mobs with no particular control of breeding. Areas where the efficiency of livestock production and grassland productivity could be improved are discussed.