Blood Biochemistry in Nellore Cows of Different Ages from the Bolivian Tropics

The objective of the work was to evaluate if the multiparous adult cows presented any difference in the values of blood biochemistry compared to young primiparous Nellore cows of the Bolivian tropics. During the month of February 2021, a study was carried out with 14 multiparous adult cows and 13 young primiparous cows, belonging to the Technology Center on Agriculture and Livestock in Bolivia (FUNDACION CETABOL) in Santa Cruz, Bolivia. The following variables were analyzed: Albumin, Total Protein, Globulin, Urea, Alkaline phosphatase, Aspartate transaminase, Glucose. The mean values and standard errors of the days of life of the cows used, according to the group they belonged to at the time of blood sampling and measurement were: Adult cows of 4561 ± 95 days and young cows of 1535 ± 99 days showing differences significant (p≤0.001). The all values of Albumin (g / dL), Total Protein (g / dL) and Urea (mg / dL) have values between normal ranges and without showing significant differences between adult cows and young cows. With the exception of Globulin (mg / dL) which has values above the normal ranges, although without showing significant differences between adult cows and young cows. The alkaline phosphatase enzymes were above the upper range, although without showing significant differences between both groups. For the enzyme aspartate transaminase, the values are between the normal ranges and without showing significant differences between both groups. The glucose values were found between the normal ranges for adult cows and for young cows and without showing significant differences between both groups. It is concluded that multiparous adult cows did not present any difference in blood biochemistry values compared to young primiparous Nellore cows of the Bolivian tropics.


Introduction
The metabolic indicators at the blood level have been used to evaluate the degree of effectiveness of the diet and the magnitude of the energy and protein imbalance [1]. However, the bovines belonging to the Bos indicus species the values of in adult cows. The search for elements necessary to sustain the benefits of the longevity of the cows would help to consolidate the search in the productive systems of the longest-lived cows.
The objective of the work was to evaluate if the multiparous adult cows presented any difference in the values of blood biochemistry compared to young primiparous Nelore cows from the Bolivian tropics.

Animals
Fourteen multiparous adult cows (Adult Group: AG) between ten and fifteen years old and thirteen young primiparous cows (Young Group: YG) between three and four years old were used. The cows of both groups were with calves at the foot and gestating at the time of taking the sample.

Feeding and Management
The herd was fed grazing managed in intensive conditions, with cultivated pastures Brachiaria decumbens (8 to 12 t / ha / year of DM), Brach aria humid cola (8 to 10 t / ha / year of DM), Brachiaria dictyoneura (8 to 10 t / ha / year of DM), Cynodon dactylon (10 to 20 t / ha / year of DM) and Panicum maximum cv mombaza (20 to 28 t / ha / year of DM) [6].

Variables to Analyze
Age at the time of sample collection: date of sample collectiondate of birth in days.

Sampling
A total of 5 ml of blood was collected from the coccygeal vein and was distributed in a Lithium heparin blood collection tube. Once the whole-blood sample is collected, testing was conducted within 2 hours (at room temperature) to prevent cellulose precipitation in the blood. The analysis is done in the Artemis Veterinarian laboratory in the city of Santa Cruz -Bolivia, for the determination of the content of Albumin (g / dL), Total Protein (g / dL), Globulin

Statistic Analysis
The means and standard errors were obtained, and it was tested whether there were significant differences between the groups (AG and YG) by applying analysis of variance to a classification criterion.

Results
The mean values and standard errors of the days of life of the cows used, according to the group they belonged to at the time of blood sampling and measurement were: AG of 4561 ± 95 days and YG of 1535 ± 99 days showing differences significant (p≤0.001).
Indicating that there are two different groups for comparison.
And the median and ranges of the number of deliveries of both groups were: AG 9 (6-12) and YG 1 (1). Table 1 shows the values of Albumin (g / dL), Total Protein (g / dL) and Urea (mg / dL) all have the values between normal ranges and without showing significant differences between adult cows and young cows. Except for Globulin (mg / dL) which has values above the normal ranges, although without showing significant differences between adult cows and young cows. Figure 1    ns (no significant); * (p≤ 0,05); ** (p≤0.001); *** (p≤0.0001)
The increase in gamma globulins could be indicating an immune response of the organism in the presence of Fasciola hepatica, increasing the rate of circulating immunoglobulins [10]. Also, the increase in the concentration of globulins occurs when there is the presence of infectious processes in the body [11].  [13]. Achieving the highest number of adult cows in the herd close to 80%, would allow from a zootechnical concept that the traits associated with biological efficiency such as longevity and reproduction of cows generate greater sustainability of the productive system [14].

Conclusion
It is concluded that multiparous adult cows did not present any difference in blood biochemistry values compared to young primiparous Nelore cows from the Bolivian tropics.