Efficient reproductive performance is mandatory for optimal milk production and profitability of dairy farmers; however fertility is affected by multiple factors including nutrition. Assessing metabolic profile of dairy animals can reveal the reasons behind the cause of infertility. In this work, comparison of the blood biochemical profile of Jersey cross-bred cows with regular cyclic and anestrus condition was done in rural areas of Puducherry region. Twenty apparently healthy cows about 3-6 years of age were divided into cyclic (Group I) and non-cyclic groups (Group II) based on the clinical conditions and presence or absence of corpus luteum on the ovaries. From the two groups, the blood samples were collected and the blood biochemical parameters including total plasma protein, blood glucose, total cholesterol, urea, calcium and phosphorus were analyzed colorimetrically. There was significant reduction in the total plasma protein and phosphorus levels in anestrus state. However, blood glucose, total cholesterol, calcium and urea did not differ between anestrus and regular cyclic condition. So the deficiency of inorganic phosphorus could be one of the nutritional factors for anestrus condition in cows of that particular location and by improving the nutritional status, fertility may be improved in these animals.
The normal development of metabolic processes depends on the exogenous contribution of the nutrients like protein, carbohydrate, vitamins and minerals, their absence or deficiency causes serious metabolic disorders with negative implications in animal health and also on the reproductive function. Normal levels of biochemical parameters are of most important in maintaining the functional integrity of the reproductive system (Niazi et al., 2003). Minerals like calcium and phosphorus play an intermediate role in the promotion of action of hormones at sub cellular levels in an integrated fashion which will regulate functions of reproduction and production of domestic animals. Cattle rearing by dairy farmers are mainly pasture based. The animals are grazed extensively on natural pastures in the open range, with minimal feed supplementation. The pastures are often limiting in quality and quantity of nutritional requirements of animals. Thus results in poor body condition, weight loss, low milk yield and delayed resumption of ovarian cycles after calving. The breeding efficiency of dairy cows is affected by a number of reproductive disorders like anestrus, endometritis and repeat breeding. Anestrus can be defined as the lack or absence of the expression of estrus; heifers are anestrus prior to puberty and anestrus often occurs in cows after each calving. Kumar et al., 2014, reported that anestrus is one of the most commonly occurring reproductive problems of cattle in India which affects livestock productivity and resulting in economic losses to dairy farmers. The problem is more severe in sub urban and rural areas of India. Pawshe et al., 2011, reported that the estimated loss from anestrus in hilly regions of Mizoram, India was around Rs.193.00 per day in cow.
Metabolic profile analysis of dairy animals can identify the reasons behind differential fertility (Jorritsma et al., 2003). So, the objective of this study was aimed to determine the blood biochemical profile in both cyclic and non cyclic anestrus Jersey cross-bred cows. The determination of these blood metabolites could then provide an understanding of the impact of nutritional status on reproduction, and thus guide in the development of management strategies to improve animal production.
Materials and Methods
The present study was conducted on apparently healthy cross bred Jersey cows at age of 3-6 years. The animals were divided into regular cyclic animals (Group I) and anestrus or non cyclic animal (Group II) based on their history, presence and absence of corpus luteum. The animals which did not express estrus signs where examined twice at ten days interval for the presence of corpus luteum (CL). Those animals having smooth ovaries with no functional CL and having no clinically detectable abnormalities in their genital tract were grouped into anestrus animals (Group II) and animals having functional CL on one of the ovaries were considered as cyclic animals (Group I). Each group contained ten animals and the selected animals belonged to small farmers in rural areas of Puducherry region which were mostly maintained on grazing for 3-6 hours per day and supplemented with mixed ration of paddy straw, green fodder with little concentrate feed. Drinking water was provided to animals ad lib.
Blood samples from the animals were collected from jugular vein using 16G needle in the heparinized vacutainer. Serum sample was also collected without the addition of anticoagulant to the blood sample. The plasma/serum was separated from the samples and analysed for biochemical profile colorimetrically viz., total plasma protein (Lubran, 1978), blood glucose (Trinder, 1969), total serum cholesterol (Allain et al., 1974), blood urea (Wilcox et al., 1967) and mineral profile viz., serum calcium (Gitelman, 1967) and serum phosphorus (Fiske and Subbarow, 1925). The completely randomized design method was followed for the experiment and the data collected were analysed statistically (Zimmerman and Donald, 1997).
Results and Discussion
The mean average levels of blood biochemical parameters in regular cyclic animals (Group I) in comparison to anestrus cases (Group II) were listed in Table 1. The results revealed no significant variation in blood glucose level between anestrus and regular cyclic cows. The observed no difference in blood glucose levels in cows with anestrus and normal cyclic conditions was in agreement with the finding of Ahmad et al., 2004. Blood urea concentration was slightly higher in regular cyclic animals (29±0.77mg/dl) in comparison to anestrus animals (27.5±0.54mg/dl) but the observed blood urea levels were non-significant between the two groups. Ahmad et al., 2004 and Majeed et al., 1990, also observed non-significant difference in blood urea among regular cyclic and anestrus animals. Plasma protein level was significantly less in anestrus group (52.7±0.63g/L) in comparison to regular cyclic animals (65.9±0.89g/L). The level in cyclic animals was significantly higher than that of anestrus animals (P<0.05). Similarly Pariza et al.,2013 and Burle et al., 1995, reported significantly higher value of total serum protein in cyclic cows in comparison to anestrus. But Ahmed et al., 2004, reported significantly higher levels of total protein in non cyclic in comparison to cyclic cows. The variation could be due to the differences in animal breed and level of nutrition. Inorganic phosphorus level was found to be significantly (P<0.05) low in anestrus (4.81±0.33mg/dl) in comparison to regular cyclic animals (6.92±0.16mg/dl). Ali et al., 2014, Kumar et al., 2010 and Amir et al., 2003 reported significantly high level of inorganic phosphorus in cyclic animals. The result of this study correlates with the report of Husnain et al., 1981, that lower level of inorganic phosphorus is an important cause of non cyclic conditions. Jayachandran et al., 2013, also reported significantly lower level of inorganic phosphorus in anestrus buffaloes compared to regular cyclic animals. Serum cholesterol level was observed to be the same in both cyclic and anestrus animals as reported earlier by Ahmed et al., 2004. During our study, it is also observed that serum calcium level was found to be similar in both the groups. This result was supported by findings of Jayachandran et al., 2013, where they reported non-significant differences in serum calcium level between cyclic and anestrus animals. But Ali et al., 2014 reported slightly high level of calcium in regular cyclic animals in comparison to anestrus animals. The difference could be due to difference in breeds and feed ration.
The observed data show that the animals in regular cyclic conditions have higher inorganic phosphorus and protein level in comparison to anestrus group. Although protein is generally regarded as less important than energy for reproduction, low protein intake in feed can also cause infertility (Rooh, 2013). Low fertility and delayed conceptions are the prime signs of phosphorus deficiency. Delayed onset of puberty and silent or irregular estrus in heifers were important clinical manifestation exhibited by the animals from phosphorus deficient areas (Cahudhary and Singh, 2004). Therefore, it is concluded that the low levels of serum inorganic phosphorus could be one of the reasons for the anestrus in the cross bred Jersey cows in the observed locality and by improving the nutritional status; fertility may be improved in these animals.
Table 1: Mean (±SE) blood biochemical parameters in regular cyclic and anestrus cows
|S. No||Biochemical Parameter||Group I (Normal Cyclic)||Group II (Anestrus)|
|1||Blood glucose (mg/dl)||49.8±0.66||48.5±0.90NS|
|2||Blood urea (mg/dl)||29±0.77||27.5±0.54 NS|
|3||Plasma protein (g/L)||65.9±0.89||52.7±0.63*|
|4||Serum cholesterol (mg/dl)||77.1±1.22||77±1.12 NS|
|5||Inorganic phosphorus (mg/dl)||6.92±0.16||4.81±0.33*|
|6||Serum calcium (mg/dl)||7.4±0.17||7.2±0.37 NS|
*Mean values observed within a row differ significantly (P<0.05); NS: Non-significant
The authors gratefully acknowledge the Dean, Rajiv Gandhi Institute of Veterinary Education and Research (RIVER) for his support and encouragement for this research study.