Evaluation of nutritional and mineral blood parameters as tools to predict Bovine reproductive conditions in the Ngaka Modiri Molema District of the North-West Province
Abstract
The aim of this study was to evaluate the nutritional and mineral levels in blood to assist in predicting the occurrence of reproductive conditions in cows. The study was conducted in Ngaka Modiri Molema District of the North-West Province in South Africa. All calls related to the incidences of reproductive conditions were recorded and blood samples collected from cows of different farmers. A total of 108 samples were collected between 2012 and 2015 from cases of reproductive conditions such as downer cow syndrome (n=13), dystocia (n=14), retained placenta (n=13), vaginal prolapse (n=9), abortion (n=28) and those from cows in the final trimester of pregnancy (n=31) reported to the North-West University teaching hospital between June 2012 and June 2015. Structured questionnaires were also used to collect data from farmers in Ngaka Modiri Molema District of the North-West Province. Farmers were interviewed during farm visits and at community outreach programmes organized by North-West University Animal Health Department. Farmers were asked about the types of conditions that their cows experience, age of the cow, breed, the body condition score, incidences of the condition, parity, whether the cows supplemented or not, and whether or not any treatment was given to the cows prior to the condition and medical history. Blood samples were screened for brucellosis by Rose Bengal Plate Test and later analysed for serum biochemical parameters such as calcium, magnesium, total protein, creatinine kinase, lipase, triglycerides, blood urea nitrogen, uric acid, Aspartate amino-transferase, sodium, chloride, potassium, cholesterol, total bilirubin and ammonia. Blood collected from cows that showed signs of abortion, retained placenta, downer cow syndrome, vaginal prolapse and dystocia were collected at the same time with the controls from cows in the final trimester of pregnancy. Data were analysed in SAS (version 20) using the analysis of variance techniques (ANOVA). The results were expressed as means ± SEM. The different treatments were significant if the associated P-value was less than the alpha level established (i.e. P<0.05). Correlation analysis was performed to see if there is association between reproductive conditions, breed types and blood chemistry between the experimental groups. The data from completed questionnaires were coded, captured and analysed using Statistical Package for Social Sciences (SPSS) version 21. Descriptive statistics (frequencies and percentages) was used to determine proportions of the different factors and how often these were experienced in rural areas.
In this study, dystocia was found to be the most frequently (26.2%) experienced condition, followed by abortion and retained placenta with equal proportions of 23.1%, then downer cow syndrome (20%). This study also established that 46.15% of the reproductive conditions occurred in cows aged between 4-6 years, followed by cows aged between 1-2 years (38.3 %). On the other hand, body condition score (BCS) did not show any significant differences (P>0.05). It was also seen that cows at first calving were mostly (41.1%) affected by reproductive conditions. Cows in this study were reported to be experiencing the conditions for the first time with abortion (100%), retained placenta (50%), dystocia (94%); downer cow syndrome (93.31%) and vaginal prolapse (80%). It was also noticed that the majority of downer cows (61.1%) had Brucellosis. Other reproductive conditions experienced with brucellosis were dystocia (50.0%) and vaginal prolapse (77.8%). The incidences of abortions in this study were found to be significantly higher (60.00%) in Brahman. The cows in the final trimester of pregnancy were mostly Brucella negative (74.2%).
The levels of calcium and magnesium in this study were found to be significantly lower than the normal range in all breeds (Afrikander, Bonsmara, Brahman, Nguni, Charolaise, Mixed breed and Drakensberger) with values ranging between 0-3.2 mg/dL and 0.32-0.7 mg/dL respectively. Calcium concentrations were significantly lower (P<0.01) than the normal range in downer cow syndrome, dystocia and cows in the last trimester of gestation. Low magnesium concentrations were seen in Afrikander, Brahman and Nguni breed in aborting cows. This study revealed that levels of aspartate amino-transferase (AST) were within normal ranges in most breeds. The mean concentrations of serum urea were within normal ranges (8–20 mg/dL) in all breeds. The concentrations of total bilirubin were above the normal ranges in all breeds, with between 8.25 mg/dL and 10.16 mg/dL. Levels of ammonia were higher than normal ranges, with values ranging between 626.00 mg/dL and 960 mg/dL in this study. Serum concentrations of triglycerides and lipase were found to be lower than normal with values ranging from 0.0 mg/dL and between (45.33 U/L -101.80 U/L) respectively. Serum triglyceride illustrated significant variations (P<0.05) only in mixed breed which experienced dystocia, downer cow syndrome and cows in their last trimester of gestation. Results obtained also showed that the mean concentrations of lipase were statistically significant (P<0.01) in aborting Afrikander and Nguni breeds. The present study also revealed that the levels of total protein were mostly above the normal ranges in most breeds with values ranging from 25.31 g/dL to 38.25 g/dL. The mean concentrations of cholesterol (CHOL) were all below the normal ranges in Afrikander (2.82 mg/dL), Bonsmara (2.95 mg/dL), Brahman (3.14 mg/dL), Nguni (3.34 mg/dL), Charolaise (1.90 mg/dL) and Drakensberger (2.67 mg/dL).
There were no significant differences in number of parity and whether or not the cows were supplemented. The results in this study show that the majority of cows in communal farming are not supplemented. The levels of disease control in communal farming areas are still lagging behind and this interferes with cow reproduction and production. Competent cattle production in communal farming requires adequate and monitored dietary needs of cows. Optimum herd management strategies are important contributing aspects in ensuring maximum production feedback. Deficiencies of trace minerals such as calcium and magnesium can influence the occurrence of reproductive conditions and impair cow fertility. However, due to the high infection of Brucella in these communal areas, it is therefore not easy to conclude that the conditions were as a result of nutritional deficiencies or brucellosis. The study was also limited in terms of formulating a reference parameter which could be used as a tool to predict the possibility of the occurrence of reproductive conditions in this study. It is therefore important to further study the incidences of these reproductive conditions with bigger samples and removing all Brucella infected samples so as to rule it out as a cause of these conditions. The results of this study are important and can be used by veterinary practitioners and farmers when dealing with such cow reproductive conditions.