EVALUATION OF DIFFERENT PROTOCOLS FOR PROSTAGLANDIN SYNCHRONIZATION TO IMPROVE REPRODUCTIVE-PERFORMANCE IN DAIRY HERDS WITH LOW ESTRUS DETECTION EFFICIENCY
W. Heuwieser et al., EVALUATION OF DIFFERENT PROTOCOLS FOR PROSTAGLANDIN SYNCHRONIZATION TO IMPROVE REPRODUCTIVE-PERFORMANCE IN DAIRY HERDS WITH LOW ESTRUS DETECTION EFFICIENCY, Journal of dairy science, 80(11), 1997, pp. 2766-2774
The objective of this study was to evaluate different PGF(2 alpha) pro
tocols against control protocols for herds with estrus detection effic
iencies of 35, 55, and 75% using modeling and simulation: 1) PGF(2 alp
ha) treatments based on the presence of a corpus luteum diagnosed by r
ectal palpation, 2) PGF(2 alpha) treatments based on the presence of a
corpus luteum diagnosed by an on-farm milk progesterone enzyme immuno
assay, and 3) PGF(2 alpha) treatments based on a 14-d fixed treatment
schedule without prior screening for ovarian status. After the start o
f each protocol, estrus detection efficiency was 75% for 7 d after tre
atment and 35 or 0% for the following week. For the third protocol, an
additional modification at estrus detection efficiencies of 85 and 55
%, respectively, in the Ist and 2nd wk after treatment was evaluated t
o establish a protocol for best case assumptions. All protocols improv
ed reproductive performance relative to that of controls with estrus d
etection efficiencies of 35 and 55%. The mean number of days open was
reduced from 124.3 d in the control herd to 95.9, 95.0, and 92.7 for t
he protocols based on rectal palpation, milk. progesterone test, and t
he fixed treatment schedule, respectively. The protocols based on a fi
xed treatment schedule were superior to protocols based on rectal palp
ation and on-farm milk progesterone tests and resulted in better repro
ductive performance and a higher increase in net return per cow per ye
ar. Relative to a control herd with an estrus detection efficiency of
55%, it was cost effective to spend up to $10 per dose of PGF(2 alpha)
, $9 per milk progesterone test, and $6 per rectal palpation.