Abstract
BACKGROUND AND AIM: Milk yield (MY) is one of the main factors that affect the economic profitability of dairy farms. Thus, increasing the MY per animal and decreasing the feed cost can lead to economic gains, so the objective of this study was to evaluate the effect of dry period length (DPL), days open (DO), and days in milk (DIM) on the productivity and profitability of dairy cow farms. MATERIALS AND METHODS: Data used in this study were taken from 3095 lactation records of Friesian dairy cows of private and governmental sectors. The data were classified into 4 DPL categories: DPL(1) <45 days; DPL(2) 45-60 days; DPL(3) 61-75 days, and DPL(4) >75 days, 3 DO categories: DO(1) ≤90 days; DO(2) 91-110 days and DO(3) >111 days, and 8 DIM categories: DIM(1) 180-210 days; DIM(2) 211-240 days; DIM(3) 241-270 days; DIM(4) 271-300 days; DIM(5) 301-330 days; DIM(6) 331-360 days; DIM(7) 361-447 days; and DIM(8) >447 days. RESULTS: The average net profit (NP) was significantly different (p<0.05) among different categories of DPL, DO, and DIM in both production sectors, where high estimates of NP were calculated for DPL(3) (30667.3 EGP), and it was the lowest for DPL(1) (19690.6 EGP). DO(2) had the highest NP (30754.1 EGP), while DO(3) had the lowest NP (24875.5 EGP). DIM(3) had the highest NP (29569.3 EGP), while DIM(8) had the lowest NP (19528.4 EGP). CONCLUSION: Finally, we can conclude that DPL 61-75 days, DO 91-110 days, and DIM 241-270 days had the highest level of total MY, total return, and NP. Private dairy cow farms achieve a higher level of NP than governmental ones under subtropical Egyptian conditions.