four hundred and ninety five smallholder dairy farms in 52 villages of different cities in chaharmohal and bakhtiari province including 1321 lactating cows and totalling 2811 total mature cows (lactating and dry)were employed during winter 2009 to summer 2010 to estimate the economic opportunities as per cow in smallholder dairy farms. a questionnaire survey was employed to collect data from th...

Records of Angus, Hereford, Shorthorn, and first-cross cows born from 1960 to 1963 were used to study the effect of age at first calving and culling policy on cumulative survival (SU), number of breeding seasons (BS), pregnancies (PG), calves born (CB) and alive at 72 h (C72) and at weaning (CW), calf weaning weights (WW), and input/output efficiency, up to 12 yr of age. The 155 cows born in 19...

The time between birth and first calving represents a period in which replacement heifers are not generating income. Instead this rearing period requires considerable capital expenditures including feed, housing, and veterinary expenses. These expenses constitute 15 to 20% of the total expenses related to milk production (Heinrichs, 1993). A basic approach to reducing this cost is to reduce the...

Two trials were conducted to evaluate one trial, pregnancy first 21 d and total pregnancy in effects of Synovex C@ implants on replacement heifers, 63-d breeding season were decreased ( P = . 0 5 ) by given at two different ages. Crossbred heifer calves ( n implanting at 6 mo. At subsequent calving, an = 370) were allotted to four treatments: 1) noninteraction existed between the effects of the...

Effects of age at first calving (AFC) on functional longevity of Czech Holstein cows and their reproduction traits in the first lactation were analyzed using the first lactation data of 605 538 Holstein cows first calved from 1993 to 2008. Three classes were formed for AFC: low age class (16–24 months), average age class (25–30 months), and high age class (33–46 months). Effects of AFC on lengt...