A. Tegegne et R. Franceschini, EVALUATION OF LUTEOLYSIS AND ESTROUS SYNCHRONIZATION USING A PROSTAGLANDIN ANALOG (PROSOLVIN) IN BORAN X FRIESIAN CROSSBRED HEIFERS IN ETHIOPIA, Journal of Applied Animal Research, 4(2), 1993, pp. 107-114
Luteolysis, oestrus synchrony and subsequent fertility were evaluated
in 32 Boran x Friesian heifers after treatment with a prostaglandin an
alog, Prosolvin. Heifers were assigned to receive 1 ml Prosolvian (ful
l), two injections of 0.5 ml each at 24 hour interval (split) or to se
rve as untreated controls. Treated heifers were mated on induced oestr
us and control heifers were mated over a 21-day breeding period Blood
samples were collected from all heifers at the time of treatment, at 1
2 hour intervals for 72 hours after treatment and every three days for
five weeks after onset of oestrus. Plasma samples were used for deter
mination of progesterone levels. Oestrus response did not differ betwe
en heifers that received either full or split dose (90 vs 73%), while
all heifers in the control group (100%) showed oestrus during the 21-d
ay period. Mean (+/- SEM) oestrus response intervals did not differ be
tween heifers that received full (86 +/- 27 h). and split (76 +/- 29 h
) dose, but were shorter (P<0.001) than in the control group (262 +/-
25 h). Both full and split doses resulted in luteolysis as indicated b
y a significant decline (P<0.001) in progesterone concentrations to 10
% of the pretreatment levels at 48 hours after treatment. Progesterone
levels after induced oestrus in heifers which received full and split
doses revealed the subsequent formation of functional corpora lutea.
Pregnancy rates were 60, 73, and 91% for heifers that received full an
d split dose, and for the control group, respectively. It was conclude
d that although luteolysis and oestrus synchrony were similar in heife
rs treated with either full or split dose, the earlier resulted in a h
igher oestrus response and minimized handling of animals.