An echographic study of follicular growth during induced estrus in female Azawak zebu in Niger.

Mahamadou Moussa Garba,Moumouni Issa,Christian Hanzen,Hamani Marichatou

doi:10.1007/s11250-015-0871-y

Mahamadou Moussa Garba, Moumouni Issa + Show 2 more

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https://doi.org/10.1007/s11250-015-0871-y

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Abstract

An echographic study of follicular growth up to ovulation was carried out on 42 lactating Azawak cows (Bos indicus) after estrus induction by means of a PGF2α or a procedure involving the administration of progesterone vaginally (PRID® DELTA: progesterone-releasing intravaginal device) for a 10-day period and the injection of a PGF2α and an ECG (400 and 800 IU) on withdrawal. All the animals were inseminated 12 and 24 h after the onset of estrus. The percentage of estrus induced was not significantly different between the two groups of animals (81 %). The average time delay before the onset of estrus was significantly longer after injection of a PGF2α (84.8 ± 26.0 h) than after withdrawal of the PRID® (59.2 ± 5.8 h). The average duration of the estrus was significantly shorter after its induction by PGF2α (12.6 ± 2.6 h) than after induction by progesterone (22.9 ± 2.7 h). There was not a significant difference in the interval between the beginning of estrus and ovulation in animals treated by PGF2α (30.3 h) and progesterone (28.4 h). Injection of a PGF2α was accompanied by a significantly lower rate of gestation than that obtained after treatment of animals by progesterone (31.2 vs 54.5 %). These results confirm the necessity to adapt an insemination policy to hormonal treatment for estrus induction in B. indicus.

Highlights

Reduced reproductive performance is one of the characteristics of cattle-breeding in Africa
On the 8th day of treatment, an injection of 25 mg of PGF2α was administered to make certain of the luteolysis of the corpus luteum that was not identified or that was insufficiently developed during the first examination
The average diameter of the corpus luteum of the cows whose estrus was induced by PGF2α determined by ultrasound was 20.0±2.7, 15.7±2.2, 13.5±2.8, 10.5±5.3, and 10.4±2.3 after 0, 12, 24, 36, and 48 h, respectively, following injection

Summary

Introduction

Reduced reproductive performance is one of the characteristics of cattle-breeding in Africa. The long interval between calving and first insemination (voluntary waiting period) is the main contributing factor in both cases. Such situation limits the genetic progress and profitability of Bos indicus breeding in particular. Different echographic studies have made it possible to identify the interval between the beginning of heat and ovulation in B. indicus which is 25.6±2.8 h in the Gobra zebu in Chad (Vounparet et al 2014), 25.8 h in the Ethiopian zebu (Mukasa-Mugerwa and Mattoni 1988), 26.6±0.4 h in Nellore female zebus after natural or induced estrus, and between 22 and 26 h in Goudali zebu cows (Wéré et al 2012a, b)

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