Oestrus synchronization and fertility in Romanov crossbred ewe using GnRH and PGF2α
Abstract: Sixty Romano crossbred ewes aged 2.5-3 years and weighing 40-50 kg, were used to compare three method of estrus synchronization. The ewes were divided randomly into three similar groups. The first group (PFP) received intravenous two injections each of 125 μg PGF2α (cloprostenol-estrumate) 11 dapart and a single intravenous injection of 20 μg GnRH (Fertagyl) 5 d prior to the second PGF2a injection. The second group (PF) was given intravenous 20 μg Fertagyl followed 5 days later by intravenous injection of 125μg cloprostenol. The third group (PP) was intravenous injected with 250 μg cloprostenol, 11 d apart, and served as control. All ewes were naturally inseminated (N1) on observed standing estrus or on fixed time 72-80 hrs after the 2nd PGF2a administration if ewes that failed to display standing estrus. Pregnancy was diagnosed 50 d post N1 using ultrasonic technique. The percentage of exhibition estrus was 55.0; 36.8 and 16.7% for the PFP; FP and PP treatments, respectively. The synchronized pregnancy rate by ultrasonic technique was 54.6; 71.4 and 100% for ewes displayed standing estrus in different three treated groups (PFP; FP and PP. respectively), while it was 44.4, 25.0 and 0.0% for ewes inseminated at fixed time in the corresponding three groups. The lambing rate was 45.0; 52.6 and 16.7% and the litter size was 1.89,1.3 and 1.0 in PFP; FP and PP freatments, respectively.
Estimated saving in hormone costs using lower doses of PGF2a and GnRH (Fertagyl) for synchronization of estrus and fertility in FP treatment were LE 3.25 and LE 8.35 per ewe and LE 8.66 and LE 69.16 per lambing less than PFP and PP treatment respectively. It was concluded that Fertagyl and cloprostenol, given 5 days apart, will produce intermediate levels of estrus were used for the current work. Animals were belongjng to the Mehallet Mousa Station, Animal Production Research Institute, Ministry of Agriculture during the anestrus period (May 31 to early summer, 2003). Ewes were housed in semi open pens under conditions of natural day length and were fed on (0.25 kg) concentrate mixture, rice straw (0.6 kg) and berseem bay according to the standard allowances recommended by the Ministrv of Agriculture. water and Minerals blocs were always available.
Ewes were allocated randomly into three equal treatment groups (20 ewes/each, Figure1). Group PFP received h\:o intravenous injections each of 125μg cloprostenol, PGF2a (Estrumate, Coopers Tiereazneimittel GmbR Burghwedel. Germany) given 11 days apart and a single intravenous injection of 20 μg GnRH (Fertagyl, Intervet, -Millsboro, DE) on days 5 prior to the second ir.jection of PG as follows: Day 0, PG; Day 6, GnRH:
Day 11, PG. Group FP. Group FP: Was treated with a single intravenous injection of 20 ug Fertagyl (GnRh) followed 5 days later by intravenous injection of 125 μg cloprostenol. Group PP: (considered as control) received two intravenous injections each of 250 μg cloprostenol (PGF2a), 11 days apart.
PFP PG GnRH PG Timed NI
FP 0 6 11 72-80h
GnRH PG Timed NI
PP 0 5 72-80h Detected heat
PG PG & NI
0 11
Fig. (1): Timeline for administration of hormones to experimental groups
All ewes were detected for the onset of estrus three times daily and ewes which were seen to be receptive and stood for mounting by the ram were considered to be in estrus. All ewes were naturally inseminated (N1) on standing estrus or on fixed rime 72-80 synchronization, fertility, less laborious and has short duration comparable with a double dose of PGF2a with or without GnRH.
Publication year 2004
Availability location معهد بحوث الانتاج الحيوانى-7 شارع نادى الصيد- الدقى - الجيزة
Availability number
Organization Name
City طنطا
serial title Journal Agricultural Research Tanta University
Author(s) from ARC
External authors (outside ARC)
    ابراهيم محمود عبد الرازق جامعة طنطا
    ابراهيم سعد الشماع جامعة طنطا
Agris Categories Animal physiology - Reproduction
AGROVOC
TERMS		 Ewes. Fertility. Gnrh. Oestrus synchronization.
Proposed Agrovoc PGF2α;
Publication Type Journal
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