Alteration of serum haptoglobin concentration in normal parturition and dystocia affected cows

This study was designed to investigate the alteration in serum haptoglobin (Hp) concentration in dystocia affected cows in comparison to those having normal parturition. Thirty cows included in this study, seventeen with normal parturition and thirteen with difficult parturition (dystocia). Blood samples, from cows that having normal parturition, were collected every three days during the last two weeks of gestation, at calving, 3, 7, and 10 days postpartum. Blood samples from dystocia affected cows were collected at calving, 3, 7, and 10 days postpartum. Serum Hp concentration was determined using ELISA. The results gradual increase of Hp concentration prepartum from 190±70 mg/L at the 10 day before calving to 250±30 and 260±100 mg/L at 7 and 3 day prepartum, respectively. At day of parturition, Hp concentration increased to 300±140 mg/L, to reach 330±150 mg/L at 3 day postpartum. Hp concentration at 7 and 10 day postpartum declined to 230±90 and 220±160 mg/L, respectively. Serum Hp of dystocia affected cows was 360±240 mg/L at calving. At 3 day postpartum, Hp increased to 660±220 mg/L. At 7 and 10 days postpartum, Hp concentration declined to 510±300 and 400±110 mg/L, respectively. No variation in Hp was observed between the cows giving twins and those giving single calve. There was no significant effect of dystocia causes on serum Hp at calving and at 3 day postpartum. It be concluded that normal calving and dystocia elevated the serum Hp concentration, and insufficient dilatation of birth canal was the most effective cause of dystocia. Also comparison of serum Hp concentration at 3 and 7 day postpartum can be used as an indicator for the development of complications.

. The function of acute phase proteins is to promote production of immunoglobulin, enhancing tissue repair and limiting the damage caused by the infection or inflammation (2).Haptoglobin (Hp) is one of an important acute phase protein.It produced mainly in the liver but it is also produced by lung, adipose tissue, skin, spleen, udder, ovary, uterus and placenta (3)(4)(5).Additional to the biological function of Hp in responses to infection and inflammation ( 6), Hp has other functions such as antioxidant, antibacterial and anti-inflammatory (7)(8)(9).
The concentration of serum Hp has been determined in farm animals as an indicator for infection and cells damage.Also it was used as a prognostic indicator for many affections (10)(11)(12)(13)(14)(15)(16)(17).
Parturition is a physiological event that includes hormonal and anatomical changes in genital system.Dystocia is defined as abnormal or difficult parturition, which can increase calf losses, cow mortality, delay return to estrus, and decrease conception rates (18).
This study was designed to investigate the alteration in serum Hp concentration in dystocia affected cows in comparison to those having a normal parturition.

Animals
Thirty cows, aged between 4 and 7 years, were included in this study, seventeen with normal parturition and thirteen with difficult parturition (dystocia).Ten healthy heifers, aged between 7 to 10 months were included as a control group.The cows were bred individually by ten different farmers.

Blood samples
Blood samples were collected once time from cows of control group.Samples from cows that having normal parturition were collected every three days during the last two weeks of gestation, at calving, 3, 7, and 10 days postpartum.Samples from dystocia affected cows were collected at calving, 3, 7, and 10 days postpartum.Blood samples were kept at room temperature for 30 min to clot, then were kept at 5°C for 24 hours.Serum was collected by centrifugation at 3000 rpm for 15 min.Serum samples were stored at -20°C until assay.

Hp assay
Serum Hp concentration was determined using ELISA as method was described previously by Hiss et al. (19).Standard curve (Figure 1) was prepared to calculate the Hp concentration in samples.

Statistical analysis
Data of study were presented as mean ± SD.T-test and one way analysis of variance (followed by Duncan's multiple range test) were used to determine the significant differences between groups.SigmaStat (Jandel scientific software V3.1) was used for statistical analyses and P<0.05 was considered as statistically significant.

Results
The mean value of serum Hp concentration in cows of control group was 150±70 mg/L (ranged from 50 to 230 mg/L).
Figure 2 shows the concentration of Hp in cows with normal parturition during the period between the 10 th day prepartum and the 10 th day postpartum.Hp concentration prepartum showed insignificant gradual increase from 190±70 mg/L at the 10 th day prepartum to 250±30 and 260±100 mg/L at 7 th and 3 rd day prepartum, respectively.At day of parturition, Hp concentration increased significantly (P<0.05) to 300±140 mg/L, and it continually increased significantly (P<0.01) to reach 330±150 mg/L at 3 rd day postpartum.Hp concentration at 7 th and 10 th day postpartum declined to 230±90 and 220±160 mg/L, respectively.Table 1 summarize the results of Hp concentration in dystocia affected cows in comparison to those having normal calving.Serum Hp concentration of dystocia affected cows was 360±240 mg/L at calving.No significant variation in Hp concentration at calving was observed between cows having normal and difficult calving.
At 3 rd day postpartum, Hp concentration in cows having dystocia increased to 660±220 mg/L.This level was significantly (P<0.01)higher than Hp concentration at calving also higher than the concentration at 3 rd day postpartum in normal calving cows.
At 7 th and 10 th days postpartum, Hp concentration declined to 510±300 and 400±110 mg/L, respectively.These levels were significantly (P<0.05)higher than Hp concentration at 7 th and 10 th day postpartum in normal calving cows.
At calving, Hp concentration in dystocia affected cows showed no significant variation between the cows that giving twins (320±80 mg/L) and those giving single calve (250±90 mg/L).At 3 rd day postpartum, Hp concentration in both groups of cows increased significantly (P<0.05)compared with that recorded at calving, but no variation was observed between these two groups (Table 2).
Hp concentration in cows having dystocia due to fault orientation, insufficient dilatation of birth canal and uterine inertia, were 280±60, 320±120 and 190±110 mg/L, respectively.These levels increased significantly (P<0.05) at 3 rd day postpartum in dystocia cases caused due to fault orientation and insufficient dilatation of birth canal but not due to uterine inertia.There was no significant effect of dystocia causes on serum Hp at calving and at 3 rd day postpartum (Table 3).

Discussion
The results indicated that no detectable variation in Hp concentration during the pregnancy.This result agree with previous studies which found no effect of pregnancy on Hp concentration (16,20).
There was an increase in Hp concentration during the last week of gestation.This result was observed previously in cows and mares (11,21).These changes in serum Hp may be occur due to the physiological changes before parturition, especially elevation of cortisone at this period of gestation (18,22).It was reported that increasing serum cortisone concentration is followed by increasing Hp concentration (21).
The results showed that serum Hp increased significantly at calving day.Same observation was recorded in cows (23), mares (11), ewes (12), and does (14).Elevation of serum Hp at calving may be occur due to the changes in estrogen level at this period, it was recorded that Hp level increased with increases of estrogen concentration (11).
Hp was increased significantly at 3 rd day postpartum, after that it declined at 7 th day and returned to normal value at 10 th day postpartum.Peak Hp concentration was observed at 3 rd day postpartum because it was produced in response to the uterine tissue damage during parturition (24).Decreasing Hp level at 7 th day postpartum and later can be attributed to the low production of Hp and destruction of serum Hp during this period because the halflife of Hp is 3.5 days (25).
Hp in dystocia affected cows was significantly higher especially at 3 rd day postpartum, which could reflect the degree of tissue damage in birth canal.Dystocia cases are more susceptible to injuries and trauma in birth canal than normal birth (18).

Conclusions
It be concluded that normal calving and dystocia elevated the serum Hp, and insufficient dilatation of birth canal was the most effective cause of dystocia on health of cows.Also comparison of serum Hp at 3 rd and 7 th day postpartum can be used as an indicator for the development of complications.

Figure 2 :
Figure 2: Haptoglobin concentration (Mean±SD) of normal calving cows (n = 17) during the period around calving.Means marked by different letters at each time were statistically different (P<0.05).

Table 2 :
Haptoglobin concentration (mean ± SD) in dystocia affected cows which having single and twins birth

Table 3 :
The effect of dystocia causes on haptoglobin concentration (mean ± SD) in cows