Abstract
Seasonal anestrus is a major constraint on reproductive efficiency in goats, severely limiting productivity under field conditions. This study aimed to evaluate the effectiveness of pregnant mare serum gonadotropin (PMSG) and nano-lipid PMSG in manipulating reproductive seasonality during the anestrus period. Sixty goats were used in the experiment and randomly assigned to four treatment groups (n= 15 per group): G1 served as the control group, G2 received 250 IU of nano-lipid PMSG, G3 received 250 IU and G4 received 500 IU of conventional PMSG. Nano-lipid PMSG was successfully formulated and exhibited desirable morphology, narrow size distribution and excellent encapsulation efficiency indicating its potential as a nano-delivery system for reproductive hormone administration at a reduced hormonal dose. Goats treated with 250 IU nano-lipid PMSG exhibited significantly improved (P ≤ 0.05) reproductive performance, achieving estrus induction, conception rate, litter size and multiple kidding rate (93.3%, 80%, 2.33± 0.19 and 91.7% respectively), compared with the goats treated with conventional PMSG (250 or 500 IU) and control groups. Progesterone concentrations increased as gestation progressed and were significantly higher (22.2±0.52 ng/ml) in the 250 IU nano-lipid PMSG group in the 4th month, and estrogen concentrations were significantly highest (60.4±5.8 pg/ml) during the 5th month of gestation of goats. Progesterone assay and B-mode ultrasonography proved to be reliable methods for early pregnancy detection with diagnostic accuracy (99.6 and 96.75%) increasing as gestation progressed. In conclusion, the present study demonstrated that nano-lipid encapsulation of PMSG improved reproductive performance in local Iraqi goats during the seasonal anestrous period. Administration of 250 IU nano-lipid PMSG resulted in significantly higher than reproductive performance compared with both conventional PMSG treatments (250 and 500 IU) and the control group.

Key words: Anestrous, Estrogen, Does, Nano-lipid, PMSG, Progesterone, Ultrasonography.