Association of Blood Progesterone Concentration with Fertility and Infertility in Nubian Does in Sudan

Abstract

The objective of this study is to establish correlations between progesterone concentrations at different stages of a controlled breeding programme and fertility rate in Nubian goats. Sixty Nubian does, were divided into 6 equal groups, according to age and body condition score. The first group A received no treatment and was naturally mated at natural heat, while the other groups B-F were treated with intra-vaginal progestagen sponges for 12 days. Group C was injected with eCG 48h before sponge removal. Group D was injected with eCG at sponge removal. Group E was injected with eCG and PGF 2a at the time of sponges removal and Group F was injected with PGF 2a 48 hours before sponges removal. All groups were inseminated with fresh-diluted semen 48h after sponge removal. Blood samples were collected from the jugular vein on the first day of treatment for oestrus synchronization (ES), mid-period of hormonal treatment (day 6), day of insemination (day of oestrus onset), day 7, day 14 and day 21 post-insemination and at ten days intervals during the period of gestation. The blood samples were centrifuged, sera separated and kept at -20°C till assayed for progesterone hormone (P 4 ) concentration using Radioimmunoassay technique (RIA). The results for the non-Return (NRR) were 50%, 50%, 60%, 60%, 50% and 40% in groups A, B, C, D, E and F respectively, with no significant difference (P! 0.05) among the groups. Pregnancy rates ranged between 30% and 50% without a significant difference (P! 0.05). Kidding rate registered no significance difference among the groups. It reached (40%) in group D and (30%) in the rest of the groups. Group D showed the highest value (kid/doe) when fecundity rates were compared among the groups, whereas the rest of the groups recorded a range of 0.4-0.7, but with no significant difference (P! 0.05). Twining rate was 100% in groups D and E, 67% in groups B, C and E and 33.3% in group F. Litter size was 2.5 in group D and ranged between 2.3 to 1.3 in the other groups without a Please purchase PDFcamp Printer on http://www.verypdf.com/ to remove this watermark. significant difference (P! 0.05). Pregnancy period was significantly longer (P! 0.05) in group B, 152.2±1.9 days, where it was 142±2.1 days in group A. The progesterone concentrations on day one in both does that carried to full term and those returned to oestrus differed according to the phase of oestrus in each doe at the time of hormonal treatment. The total mean of the P 4 concentrations on this day was 14.04±9.63 nmol/l and 12.91±5.25 nMol/l in does that carried to full term and those returned to oestrus, respectively, with no significant difference. At the mid-period of treatment, the total mean of P 4 registered a higher concentrations that reached up to 26.92±12.90 nmol/l and 23.70±9.98 nMol/l in goats that carried to full term and those returned to oestrus, respectively, without a significant differences (P! 0.05). Progesterone concentration then significantly (P! 0.05) declined to its lowest concentrations on the day of insemination (oestrus), the total mean of P 4 concentration was 1.71±0.86 nMol/l and 3.86±6.01 nMol/1 in does that carried to full term and those returned to oestrus, respectively. Seven days after insemination, the total P 4 mean was found to increase significantly in goats that carried to full term to (33.81±9.97 nmol/ml) compared to those returned to oestrus (11.56±7.89 nmol/l). On day 14 post-insemination, the mean P 4 concentrations significantly (P! 0.05) increased with the progression of pregnancy in the goats that were carried to full term, the total mean registered was 35.77±15.91 nmol/l, where as in the goats that returned to oestrus it was 19.31±18.29 nMol/l. On day twenty one after insemination, the total mean P 4 concentration in the goats that were carried to full term was 33.36±16.65 nmol/l where as in the goats that returned to oestrus the total mean level P 4 decreased to 3.67±6.99 nmol/l with a significant difference (P! 0.05) between the two groups. During the first days of pregnancy the progesterone levels rised sharply compared to oestrous levels then, they were maintained at high levels with fluctuating peaks throughout pregnancy, until 2-3 days prior to parturition when they abruptly declined on the Please purchase PDFcamp Printer on http://www.verypdf.com/ to remove this watermark. day of parturition. The progesterone concentrations significantly (P! 0.05) varied among the does through the period of pregnancy but were not affected by the treatments. However, four does in groups A, C, D and E recorded sudden decline in P 4 levels between days 30-95 of pregnancy indicating embryonic mortality. It was noticed that group D which showed the highest percentages in kidding rate, fecundity, twinning rate and litter size, also registered the highest P 4 concentrations at mid-period of progesterone sponges treatment, day 7 and day 21 postinsemination. These results illustrated the importance of progesterone assay in detection of early pregnancy, early embryonic losses and in studying fertility indices in the Sudanese Nubian does.