The aim of the study was to find the levels of serum ionized calcium and some macro-minerals during peri-partum period in Berari goat. Twelve advanced pregnant Berari goats were used for the study. Blood samples were collected on -14 day and -7 day before expected date of kidding and subsequently on the day of kidding (0th day), 7th, 14th and 21th day postpartum. Serum samples were collected for estimation of ionized calcium (iCa), total calcium, phosphorous and magnesium. Serum ionized calcium increased significantly from the day of kidding through 7th, 14th and 21st day postpartum with mean reference range of 4.19 ±0.18 to 4.89±0.16 mg/dl during peri-partum period in Berari goat. These values are almost half of the value reported for total calcium. Serum total calcium shown increasing trend through day 14th, 7th prepartum, day of kidding (0th day), 7th, 14th and 21st postpartum. Serum Phosphorus has shown increasing trend during entire peri-partum period. While magnesium has shown lowest value on 7th day postpartum without any specific trend. There was significant (p<0.05) positive correlation between levels of ionized calcium and total calcium and magnesium during peripartum period in Berari goat.
Berari is recently recognized as 23rd goat breed of India, a breed of Vidarbha region of Maharashtra, is low yielding prolific meat breed thriving well in tropical, wet and dry climate. Three weeks before and three weeks after parturition the period as marked by several metabolic alterations and adaptation to new physiological status of the animal consider very critical called as transition period (Araújo et al., 2014). Level of plasma calcium during different physiological stages may vary (Shappel et al., 1987 and Goff et al., 1989). Goats metabolize calcium more efficiently during early lactation when calcium is drained in the milk. When serum calcium levels are decreased, usually less than 6 mg/dl (normal range 8-12 mg/dl) commonly known as milk fever. Although it is generally accepted that ionized calcium is the metabolically active form in the extracellular fluid, it is seldom measured. The measurement of free calcium is clinically more useful. The advantage to measuring ionized Ca is that it tends to be less variable than total plasma Ca (Szenci et al., 1994.). The Ion Selective Electrode (ISE) method currently used for the estimation of electrolytes is the most accurate and rapid method for ionized calcium estimation. Magnesium involved in many physiological functions such as activation of various enzyme system (Romani and Scarpa, 2000). Magnesium plays a key role as an extracellular ion for nerve transmission. Hypomagnesaemia (tetany) occurs during the early stages of lactation in goats. Reproductive problems such as low first service conception rates and silent heat have been related to wide Ca:P ratio and to phosphorus deficiencies.
Materials and Methods
Twelve advanced pregnant Berari goats aged between 2 to 5 years and body weight ranging between 28-30 kg were selected from Berari Goat and Deccani Sheep Research, Demonstration and Training Centre, Borgaon (Manju), MAFSU, Akola, Maharashtra. Blood samples were collected from the jugular vein puncture during morning hours on 14day and 7day before expected date of kidding and subsequently on the day of kidding (0th day), 7th, 14th and 21th day postpartum in clot activator sterilized tubes. Clear serum was separated by centrifugation. Serum macro minerals viz. total calcium, phosphorous and magnesium were estimated by using biochemical semi auto analyzer and standard kits supplied by AGD biomedical. Serum ionized calcium (iCa) was estimated by Electrolyte Analyzer by using Ion Selective Electrode (ISE).
Analysis of variance of the data was done by using Completely Randomized Design (CRD) and to study relationship correlation coefficient was calculated according to Snedecor and Cochran (1994).
Results and Discussion
Mean ± SE levels of ionized calcium, total calcium, phosphorus and magnesium during peripartum period in Berari goat is shown in Table 1 and correlation of iCa with these macro minerals during peripartum period in Berari goat is presented in Table 2.
Total Calcium (tCa)
The results show that, on the day of kidding (0thday) 8.19±0.18 mg/dl value was recorded. The lowest value of 7.40±0.14 mg/dl was obtained on the 14th day of prepartum and highest value of 9.99±0.17 mg/dl on 21st day of postpartum. The total calcium level was increased from day 7th day prepartum to 21st postpartum. The level of total calcium during prepartum period ranged between 7.40±0.14 to 8.03±0.13 mg/dl, on the day of kidding (0th day) 8.19±0.18 and during postpartum period ranged between 8.95±0.14 to 9.99±0.17 mg/dl. Serum total calcium level on 14th day prepartum showed significant (p<0.05) increased on 7th day before kidding and remained almost similar on the day of kidding (0th day). After kidding total calcium concentration showed significant increased through day 7th, 14th and 21st of postpartum. Total calcium has shown steady increased from day 7 prepartum to day 21st postpartum throughout the experimental period. Gurgoze et al. (2009) observed similar trend of calcium level during prepartum and postpartum period in Awassi ewes. However, Talawar et al. (2016) reported significant (P<0.05) reduction in blood serum calcium concentrations in the group of pregnant ewes as compared to control and postpartum group. The levels obtained in present study were agreement with the results reported by Azab and Abdel- Maksoud, (1999); Iriadam, (2007), Soares et al. (2018) in goats and Teleb et al. (2014) and Sharma et al. (2015) in ewes. The decrease in calcium concentration at late gestation could be attributed to increased demand for calcium for mineralization of foetal skeleton and also owing to their supply to the foetal tissue to meet out the increased demand of growing foetus reported by Talawar et al. (2016). Kaushik and Bugalia (1995) reported drop in circulatory concentration of calcium before and at kidding are consequential to mammary drain in colostrum as well as reduced dietary intake and calcium absorption in gut.
Table 1: Mean ± SE levels of ionized calcium and macro-minerals during peripartum period in Berari goat
|Parameter||Prepartum Period||Day of Kidding||Postpartum Period|
|14th Day||7th Day||0th Day||7th Day||14th Day||21st Day|
|Total Calcium (mg/dl)||7.40d±0.14||8.03c±0.13||8.19c±0.18||8.95b±0.14||9.76a±0.11||9.99a±0.17|
|Ionized Ca (mg/dl)||4.43bc±0.14||4.50abc±0.14||4.19c±0.18||4.52abc±0.13||4.62ab±0.13||4.89a±0.16|
|Phosphorus (mg/dl)||4.70c ±0.15||5.24c±0.28||5.98b ±0.20||6.54b ±0.24||7.42a ±0.23||7.76a ±0.13|
Means with common superscript does not differ significantly
Table 2: Correlation of ionized calcium with macro-minerals during peri-partum period in Berari goat
Ionized Calcium (iCa)
The ionized calcium concentration on the day of kidding (0th day) 4.19 ±0.18 mg/dl value was recorded. Serum ionized calcium level on 14th day prepartum showed significant (p<0.05) increased on 7th day before kidding. The values decreased significantly (p<0.05) on the day of kidding (0th day). After kidding ionized calcium concentration showed significant increased through day 7th, 14th and 21st of postpartum. Ionized calcium (iCa) level recorded lowest on the day of kidding whereas highest on 3rd week after post-partum. Serum iCa level ranged between 4.19 ±0.18 to 4.89±0.16mg/dl during prepartum and postpartum period in Berari goat. The level of iCa recorded in Berari goat in our study is almost half of the level of total calcium recorded, similar finding is also recorded by Caprita et al. (2013) in broiler chickens. Riond et al. (1995) reported average serum Ca 2+ concentrations 52% of those of total calcium. Belonje (1976) reported ionized calcium in lactating ewes and in day old suckling lamb were 4.25 ± 0.49 mg/100 ml and 4.47 ±0.65 mg/100 ml respectively. Dauth et al. (1984) pointed out an importance of ionized calcium estimation for veterinary surgeons and other people involved in the diagnosis and treatment of milk fever. The analysis is easy, cheap, instantaneous and reliable as compared with total calcium. Sava et al. (2005) reported that serum iCa reflect true calcium status of body in health and diseased condition. They suggested that in human being the Ca++ levels are independent of serum protein status. However, Agnes et al. (1993) reported that serum pH decided the concentration of ionized calcium as it is negatively correlated with ionized calcium. Ballantine and Herbein (1991) studied levels of ionized calcium in Jersey and Holsteins cows during different stage of lactation. They reported that Jersey cows had lower total calcium (7.47mg/dl) and ionized calcium (4.25mg/dl) than Holsteins cows (8.10 and 4.66 mg/dl). On day of calving the levels of iCa in Jersey cows are in comparable with our results on the day of kidding (0th day) in Berari goat. Changes in the level of ionized calcium may indicate the contribution of integrated hormonal response occurring during day of kidding in the goat. Tan et al. (1972) also reported decreased of the ionic calcium with the progress of pregnancy in women.
In present study the levels of ionized calcium increased significantly (p<0.05) from day 7th,14th and 21stpostpartum.However in contrast to our study in Berari goat, Riond et al. (1995) reported significant decrease level of serum ionic calcium during day 1 and day 2 postpartum in Brown Swiss and HF dairy cows. Mean plasma ionized calcium during early lactation in our study is in agreement with the levels (4.25 mg± 0.49 /100 ml) reported by Belonje, (1976) in lactating ewes. The literature regarding the level of serum ionized calcium during peripartum period in goat is scanty. Some workers have studied the levels of ionized calcium in other animals during pregnancy and lactation.
On the day of kidding (0th day) the phosphorous concentration value of 5.98±0.20mg/dl was recorded. The lowest value recorded on 14th day of prepartum and highest values recorded on 21st day of postpartum. The levels of phosphorus increased steadily from 14th day pre-partum to 21st day postpartum during peripartum period in Berari goat. The values of prepartum in comparison with day of kidding and subsequently on the day postpartum differ significantly (p<0.05). From the 7th day onwards it was increased significantly up to 14th day postpartum. Phosphorous concentration ranged between (4.70±0.15 to 7.76±0.13 mg/dl) during peripartum period in Berari goat. This range is slightly higher than the values recorded by Krajnicakova et al. (2003) in goat. Our result shows highest concentration of phosphorous on 21stday post-partum. Similar findings recorded by Tanritanir et al. (2009) in Sirt hair goat, Sansom et al. (1982); Ozyurtul et al. (2007) in ewes and Shinde and Sankhyam (2007) in goat. Alacam et al. (2008) reported lowest phosphorous concentration on 20th day post-partum in cattle. The trend of phosphorus has showed steady increase from 14th day prepartum up to 21st day post-partum. This might be due to maternal bone resorption of available phosphorus to the fast growing foetus inside the uterus for skeleton mineralization. The ever increasing demand of phosphorous by fast growing foetus could be fulfilled by absorbing available phosphorous from circulation or reabsorption from the bones of dam. As dam prioritize the fetus rather than herself (Gurgoze et al., 2009) and also may be due to increase in metabolic process during early lactation, hormonal response in postpartum. However, Krajnicakova et al. (2003) reported non-significant differences in phosphorus levels at the different stages of growth, reproduction, pregnancy and lactation in goat.
On the day of kidding (0th day) 3.12±0.23 mg/dl value of magnesium concentration was recorded. Serum Mg concentration was lowest on 7th day postpartum and highest values on 21st day post-partum in Berari goat. Serum magnesium showed significant (p<0.05) increased on 7th day of prepartum and on the day of kidding then the level slightly decreased on 7th day of postpartum. The levels of Mg show non-significant increasing trend after 7th day through day 14th and 21st postpartum. Similar trend was also obtained for phosphorous levels in our study in Berari goats. The values of serum Mg increased significantly (p<0.05) from day 14 pre-partum to day of kidding (0th day). After kidding Mg concentration increased but this increase was statistically non-significant. Our finding corroborated with the values reported by Ozyurtul et al. (2007); Sharma et al. (2015) in ewe, Kulcu and Yur (2003) in cow and Shinde and Sankhyam (2007) in goat. The present results are not in agreement with the report of Sansom et al. (1982), they reported plasma Mg concentration were higher during last 3rd week of pregnancy but decreased at lambing and for 3rd weeks after lambing in ewes. Azab and Abdel-Maksoud (1999) recorded plasma Mg significantly (P<0.05) increased at 4 and 3 weeks before parturition and decreased (P>0.05) at 2 and 1 weeks before parturition. This decrease was significant (P<0.05) on the day of parturition in goats. Boudebza et al. (2016) reported highest Mg level in late gestation than on early lactation and during dry periods in ewes. Brenner and Seidel, (1976) in ewes and Talawar et al. (2016) in goat reported no significant change in mineral concentrations at the time of parturition. There was transient increased of Mg2+ concentrations than the total Mg during periparturient period signifies the metabolic importance of magnesium concentration (Riond et al., 1995). The change could be carried by physiochemical alteration from mother to the fetus as the magnesium subsequently required for normal skeletal development in fetus while it is constituent of milk in dam.
Correlation of Ionized Calcium with Macro Minerals during Peripartum Period in Berari Goat
There was significant (p<0.05) positive correlation (r =0.536) between ionized calcium and total calcium. Also significant (p<0.05) positive correlation between ionized calcium and magnesium (r=0.480). Total calcium has shown significant (p<0.05) positive relationship with magnesium (r=0.268) and non-significant positive correlation with phosphorous (r =0.002). Serum magnesium level has shown positive significant (p<0.05) correlation with phosphorous (r =0.382) during peripartum period in Berari goat.
The levels of ionized calcium and macrominerals viz. total calcium. Mg and P were estimated during the peri-partum period of the Berari goat. The main objective of the study was to find out the levels of iCa during the peri-partum period of these goats by using ion selective electrode (ISE). The ISE is the most convenient, accurate and reliable method for the estimation iCa. In our study the iCa levels were almost half the levels of the total calcium. This indicate that the half of the calcium in the blood is in ionized form i.e. biologically active form in these animals serum ionized calcium increased significantly from the day of kidding through 7th, 14th and 21st day postpartum. Serum phosphorus shown increasing trend through day 14th, 7th prepartum, day of kidding (0th day), 7th, 14th and 21st post-partum. Serum Mg concentration lowest on 7th day postpartum and highest values on 21st day postpartum without any specific trend. There was significant positive correlation between serum ionized calcium and total calcium and magnesium level during peri-partum period in Berari goat.
Considering the biological importance of ionized calcium and to establish its normal reference range and cut off value of iCa for the accurate diagnosis of various metabolic disorders during peri-partum period in these goats, it is necessary to study this parameter through entire gestation period with more number of samples along with total calcium, total protein, pH and vitamin D status in healthy and animals with subclinical and clinical hypocalcaemia.