Effect of some hormones on reproductive performance and some serum biochemical changes in synchronized black goats

In randomized block design, 58 indigenous black mountain goats were examined for the effect of different hormonal treatments in inducing oestrus on selected biochemical characteristics of blood serum that were (aspartate transaminase, AST. Alanine transaminase ALT, Akaline phosphatase, ALP, total protein, albumin and total cholesterol). The animals were randomly assigned into four groups according to their treatment. The control group (C) consisted of 10 females whereas the rest of the groups, each consisted of 12 females. The treatments included a double PGF2α (Dinoprost tromethamine) intramuscular injection (5 mg) at a time interval of 11 days plus an intramuscular injection of pregnant mare serum (PMSG) (400I. Uand 600I. U.) two days before second injection for (treatments, TI, T2) respectively. Treatment (T3) was as that of T1 except PMSG was not injected. T4 was treated as T3 plus an intramuscular injection of gonadotropin releasing hormone (GnRH) (12. 5μg) after 24 hours of second injection of PGF2α was added. The results indicated that oestrus was higher (P<0.05) in all treatment groups (100%, 91%, 100%, 100%) respectively than that of control group (70%). There was a significant effect (P<0.05) of hormonal treatment on kidding rate in which the ratio were (116%, 115%, 75% and 83%) for treatment groups respectively in comparison with 70% for control group, also there was significant effect (P<0.05) of hormonal treatment on litter size in (T3). There were significant increases in activity of AST, ALT, during late pregnancy and the first week of parturition, whereas the activity of ALP enzyme was increased during early pregnancy. The concentration of total protein, total cholesterol and albumin were increased (P<0.05) during late stage of pregnancy and then decreased during the first week after parturition. It was concluded that administrating of PGF2α to does on this synchronization regimen in the natural breeding season is desirable.


Introduction
Kurdistan native goats breeding are carried out extensively for meat and milk production.The boosting goats production are by using synchronization of estrus conjunction with either natural or artificial insemination.
Synchronization of estrus remains a tool with great potential in controlled breeding of sheep and goats has involved the artificial manipulation of ovaries varies in goat when estrus period are synchronized during breeding season (1).
Prostaglandin has been shown to induce luteolysis in the cycling doe during the breeding season.The effectiveness of double injection regime of PGF 2 α for synchronization of estrus by natural mating in goats was reported (5) although conception rate was high with no adverse effective fertility (6).
This study was initiated to compare the effectiveness of synchronized technique in the normal breeding season does treatment with PGF 2 α alone or combined with pregnant mare's serum gonadotropin (PMSG) or with gonadotrophin releasing hormone (GnRH) to examine the estrus appearance and to parameters determine fertility and conception rate.In addition the alteration in biochemical of blood serum during estrus cycle, pregnancy and at parturition were examined.

Materials and Methods
The experiment was conducted during breeding season (September 2001 to April 2002) at north part of Iraq.Fifty eight breeding cyclic does of local non-descript breed, average weight 34±0.3 kg and aged 1.5-2 years.The animals were divided randomly into four treatment groups including 12 does for treating except control group which estimated of 10 does.
The animals in four treatment groups were treated as follows: Three Black bucks (local-breed) 3-4 years old were used to service all does by handing-mating twice daily during standing estrus in each group.The bucks were evaluated before experiment by a breeding soundness examination.
For biochemical analysis of serum, a blood sample was collected by jugular vein-puncture using non-heparinzed vacutainer tubes.Serum was harvested and stored at freezing (-20C) for later assays. 1 Enzymes determination: The blood serum was determined for activities of Aspartate transaminase (AST) (Glutamic Oxaloacetate transaminase, GOT) enzyme according to (7) method and Alanine transaminase (ALT) (Glumate Pyruvate transaminase, GPT) enzyme according to (8) method, whereas activity of Alkaline Phosphates enzyme was determined by using (9) method. 2 Non enzymes, determination of serum Total protein by using Biuret method (10), while the concentration of albumin was determined according to (11) method.Total cholesterol concentration was analyzed used by (12) method.
Statistical analysis: The results were analyzed statistically using SAS ( 13) assuring the following model: Where: Y ij : The value of j observation having ith treated U : overall mean.T i : Effect of ith treated (i=control, 1, 2, 3 & 4) e ij : Experimental error assuming to be NID with (o, I σ 2 e).
The model which used to analyze the results of Biochemical traits include the effect of period (Pj) beside the above effects: Comparison between means of each factors were tested by Duncan Multiple Range test.

Results
Estrus response of does following double PGF 2 α injection alone or with PMSG and GnRH was higher (P<0.05) in four treatment groups (100%, 100%, 91%, 100%) respectively than control group 70% (Table 1).There were no significant effects of hormones used in this study on fertilization and fertility, but there was existence of significant effect (P<0.05) of hormonal treatment on kidding rate in which the ratios in four treated groups, were higher than the control value (Table 1).The hormonal treatment a significantly (P<0.05)increased litter size ratio in four treatment groups (Table 1).
There was significantly increases (P<0.05) in activity of AST in the blood serum during estrus phase in comparison with luteal phase whereas there were no significant differences in the activities of (ALP) and (ALT) during estrus and luteal phases.There was no significant effect of hormonal treatment on the activity of blood enzymes (AST, ALT, ALP) (Table 2) and concentration of total protein, albumin and total cholesterol in treated groups (Table 3).The activity of AST was increased significantly (P<0.05) during second semester of gestation (Table 2), and it's highest activity during first week after parturition in comparison with the last month of pregnancy.ALT activity increased significantly (P<0.05) during five months of gestation and also at first week of parturition (Table 2).The activity of ALP was increased significantly (P<0.05) during early pregnancy and it reached it's highest activity in the second month of pregnancy and decreased gradually during last three months of pregnancy (Table 2).
The concentration of total protein increased significantly at the late pregnancy and decreased during the first week after parturition, total cholesterol at the late pregnancy and declined during first week of parturition, albumin was decreased significantly (P<0.05) during the first week of parturition in comparison with late pregnancy (Table 3).

Discussion
The results have shown that PGF 2 α given 11 days apart was effective for synchronization of estrus in cycling does.The 10 mg. was sufficient to produce lutolysis in does.The ratio of estrus in females that were treated with PGF 2 α alone or combine with PMSG or GnRH have highly significant difference from control group.These observations are similar to those reported by (14,15).The results showed increased level of fertilization and fertility in treated groups mainly with it PGF 2 α alone or combine PMSG or GnRH (1), while was differed from those obtained by (16) who observed that lack effect of PGF 2 α in fertilization and fertility.Kidding rate was highly significantly in treated groups than control group.The combination of PGF 2 α with 600 IU/PMSG had more kidding rate, this more likely due to PMSG treatment, since PMSG is needed to stimulate the follicular growth leading to higher ovulation rate (14).
Litter size was increased in treated groups and mainly in T3 group (600 IU/PMSG) due to increased rate of ovulation and this causes an increase in litter size (17).
Biochemical indices analyzed in the present study showed increased AST, ALT and ALP activities during estrus phase, but it was less than that observed by (18).This may be due to differences in animal's age, breed and season.There was no significant effect of hormonal treatment on the enzyme activities (AST, ALT and ALP), but the pregnancy was influenced on concentration of AST and ALT enzymes (19) and mostly in the second period of gestation (20) and during first week of parturition (19).The increased activity of AST and ALT enzymes may be due to more requirement for amino acids in milk production (21).There was wide variation in the activity of ALP enzyme during pregnancy, the highest value for serum ALP was noted at the second and third months of pregnancy, and decreased at late stage of pregnancy due to formation skeleton bone tissues of the fetus (22).The serum protein studies indicated an increasing in total protein and albumin values during pre-parturition stage and decreased nonsignificantly at post-parturition stage.Hence it can be stated the marked decreased in plasma protein during postparturition may be due to transfer of protein into colostrums (23).Total cholesterol concentration in blood serum was increased significantly during pregnancy period this may be due to enhanced progesterone synthesis in the placenta (24), and it's decline after parturition due to estrogen which decreased the plasma LDL (25).

Table 1 :
Treatment effects on Fertilization, Fertility, Kidding-rate, Estrus and Litter size in goats.

Table 2 :
The effect of treatment on serum enzymes activities in goats.

Table 3 :
The effect of treatment on the serum total protein, albumin, cholesterol activities in goats.