Serum protein profile
The mean concentration of total protein and albumin decreased significantly (p<0.05) from group-I to group-III (pre-partum to post-partum period) as shown in Table 1.
Table 1: Biochemical parameter changes during transition period in buffaloes.
Similar findings were seen in study of Ashmawy (2015)
, with significant decrease (p<0.05) in total protein (g/dl) levels from pregnant to early lactation group. However, non-significant difference (p>0.05) among the mean concentrations of total protein, albumin and globulin were seen in study of Abdulkareem (2013
), conducted on riverine buffaloes of Iraq during transition period. Serum protein profile in dairy cows has been reported earlier with similar findings of Mohri et al., (2007)
with decrease in protein profile from late pregnancy to early lactation reflecting the requirement of protein source for lactation and providing immunoglobulins. In last trimester of pregnancy with prevailing endocrine situations, there may be insulin resistance and decreased level in insulin growth factor-1, which can cause net mobilisation of amino acid reserves and decreases the plasma level of albumin and protein (Block et al., 2001).
Albumin is considered as negative acute phase protein and it may get decreased during transition period due to encounter of high inflammatory responses (Bionaz et al., 2007).
Serum liver enzymes
A significant increase (p<0.05) in the mean± SE values of serum glutamic-oxaloacetic transaminase (SGOT) has been observed in buffaloes of Group-I to Group-III (Table 1). The levels of Gamma-glutamyl transferase (GGT) (U/L) showed significant (p<0.05) difference with highest value in group II (24.33±0.14) as compared to group I (15.38±0.18) and group III (21.29±0.20). Whereas, highest level of Serum glutamic pyruvic transaminase (SGPT) (U/L) was observed in group III (Table 1). Mills et al., (1986
) and EA Mohammed et al., (2019)bserved
high level of SGOT during calving and postpartum period indicating of stressed hepatic metabolism and pronounced catabolism of body reserves. Similar findings related to levels of SGOT and SGPT were found in the study of Grasso et al., (2004), Abdulkareem (2013)
, and Fiore et al., (2017)
with no significant changes in the concentration of GGT (U/L). The changes in the concentrations of liver enzymes indicate metabolic disorders with involvement of liver even at sub-clinical levels (Fiore et al., 2015).
Serum lipid profile, Urinary nitrogen and creatinine
The mean values showed significant decrease (p<0.05) in the level of cholesterol and triglyceride as transition period progresses (Table 1 ). Similar findings were found in study of Karapehlivan et al., (2007)
and Rambachan et al., (2019)
with low level of triglyceride as progression of lactation occurs, as they are believed to be used by the mammary glands for production of milk fat. Kweon et al., (1986)
observed that higher rate of disease occurrence in cattle with low cholesterol level at the time of calving. However, the observation of Singh et al., (2012)
are not in accordance to our findings with non-significant difference (p>0.05) in cholesterol level (mg/dl) among buffaloes in different transition stage. Total cholesterol reflects the indirect availability of exogenous source along with hepatic functionality (Grum et al., 1996).
The level of serum cholesterol (mg/dl) may get decreased during calving and got build with progression of lactation in response to physiological adaptation. In ruminants, cholesterol and triglyceride are transported from liver via
lipoproteins and these lipoproteins get decreased during periparturient period (Katoh, 2002)
which eventually leads to decrease level of cholesterol and triglyceride around calving (Akamatsu et al., 2007).
There was significant (p<0.05) increase in the level of urinary nitrogen (mg/dl) from 0 day to +30 days. Roubies et al., (2006)
observed that level of BUN are influenced by many actors viz
dietary intake, protein quantity in feed, rumen degradability and catabolism of body reserved protein. The significant increase (p<0.05) in the concentration of creatinine during calving is suggestive of dehydration causing decreased glomerular filteration whereas, decrease in their level during post-partum period points toward skeletal muscle wasting (Megahed et al., 2019).
Serum electrolyte concentrations
The calcium level (mg/dl) showed significant decrease (p<0.05) from Group-I to Group-II buffaloes (Table 1), where as non-significant difference (p>0.05) was observed between Group-II and Group-III. For phosphorus level, non- significant (p<0.05) decrease in the Group-I and Group-II was seen. But there was a significant decrease (p<0.05) in the mean±SE values of Group-III from other two’s. Mean±SE values of Ca:P ratio showed significant decrease (p<0.05) from Group-I to III, with lowest value seen in Group-II. Similar findings were found in Kronqvist et al., (2011)
study in which calcium level decreased from 0 day, 2, 4 and 7 days after calving till peak lactation attains. Wu et al., (2008)
also observed that calcium level of plasma on the day of calving was significant lower than the prepartum period (8.33 vs 9.30 mg/dl). Parathyroid hormone regulates the level of calcium via stimulation of osteocytic osteolysis mechanisms that releases calcium from lacunae to blood stream (Hernandez-Castellano et al., 2020)
. During the lactation, calcium homeostasis becomes less effective in high yielding cattle (Kovacs, 2011)
. The Mean±SE values of sodium and potassium (mEq/L) showed non-significant (p<0.05) decrease from Group-I to Group-II, whereas significant decrease (p<0.05) in the Group-III was observed. Serum magnesium level (mg/dl) showed a significant decrease (p<0.05) from Group-I to Group-II, but there was non-significant (p>0.05) decrease amongst Group-II and III (Table 1). The decrease in the potassium level during postpartum period was seen in study of Jacob et al., (2011)
suggesting of transfer of the cation in the milk during lactation. Skrzypczak et al., (2014)
reported that lower Na+ concentration in the first week of lactation could be due to Na loss associated with decreased plasma rennin activity. Additionally, Asif et al., (1996)
indicated that as a consequence of high prostaglandin concentrations, which increase excretion of Na+ by the kidneys, significant decrease in blood Na+ concentration can be seen.
In our study, the blood concentration of WBC (x10³/µl) in all the groups increased significantly (p<0.05) with highest values in Group-III (7.57±0.09). The levels of lymphocytes and granulocytes as depicted in Table 2 differ significantly (p<0.05) in all three groups, with highest value in Group-II particularly. Similar findings were found in the study of Preisler et al., (2000)
with increased amount of WBC, lymphocytes and neutrophil due to rise in concentration of cortisol at the time of calving. Cortisol is suppose to cause demargination of neutrophil from endovascular linings eventually leads to increase concentration of neutrophil in peripheral blood circulation (Shoenfeld et al., 1981).
The mean±SE values of RBC’s (106/µl) and Hematocrit (HCT %) in all the groups as depicted in Table 2 showed significant (P<0.05) decrease in Group-II from other groups.
Table 2: Haematological parameters during transition period in buffaloes.
Similarly, haemoglobin (Hb, g/dl) decreased significantly (p<0.05) along the progression of transition period from -30 days to +30 days (Table 2). Our results showed agreement to the findings of Gavan et al., (2010)
who observed a marked reduction in the values of RBC, Hb and HCT in periparturient period. Kumar and Pachauri (2000)
observed that Hb concentration in blood decreases during the calving time that might be due to decreased erythropoiesis in periparturient buffaloes. Chikazawa and Dunning (2016)
suggested that during time of parturition, there is increased in level of pro-inflammatory cytokines (TBF-alpha and interferon’s) which are inhibitors of erythropoiesis through the action on erythroid precursors in bone marrow. Also significant increase (p<0.05) in the levels of platelet count has been observed along the transition period, suggestive of activated COX-2 pathway (cyclooxygenases) which ultimately increases the activating platelet factors and thromboxane A2 (Sordillo et al., 2009).