Hematological profile of East African short-horn zebu calves from birth to 51 weeks of age

Hematochemical profile of Cholistani cattle being reared in the Cholistan desert of Pakistan under pastoralism

ABSTRACT The objective of the present study was to assess and create normal reference intervals for hematochemical profile of Cholistani cattle (n=360) being reared under pastoralism. The comparisons have been made with earlier published data on Bos indicus and taurus cattle breeds. The general health status of animals was ascertained through a thorough anamnesis from the livestock owners and clinical signs. However, theileriosis, in specific, was ruled out through blood smear examination. The animals were assigned in groups according to age: young (n=190; ≤12 months) and adult (n=170; >12 months up till 7 years); and gender: male (n=182) and female (n=178) cattle. The mean (±SE), median, range and reference intervals (25th to 95th percentile) for hematochemical profile were determined through descriptive statistics and differences between various groups were analyzed through Mann Whitney U test. The findings of this study may serve as reference hematochemical values for Cholistani cattle in specific and humped zebu cattle in general for assessing any physiological, pathological, or metabolic alterations.

Haemato-biochemical characterization of fasciolosis in Gir cattle and Jaffrabadi buffaloes

A total of 438 faecal samples of Gir cattle & Jaffrabadi buffaloes were examined by sedimentation technique and out of these, only 10 (2.28%) samples were found positive for Fasciola infection. Overall, the highest incidence of Fasciola infection was noticed in Jaffrabadi buffaloes (2.65%) than Gir cattle (1.72%) without significant difference (p > 0.05) between two species of animals. Haematological changes of Fasciola infected indigenous bovines showed the significant (p < 0.05) reductions in the mean values of haemoglobin (Hb), total erythrocytes count, packed cell volume, lymphocytes, and monocytes while total leucocytes count (TLC), mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, neutrophils, and eosinophils were increased significantly (p < 0.05). Biochemical analysis revealed hypoproteinemia, hypoalbuminemia as well as a significant increase in total bilirubin, Gamma-glutamyltransferase (GGT) and Alanine aminotransferase (ALT). The data presented here will not only help the epidemiologist but also help the field veterinarians in prognosis, diagnosis and planning the treatment and control strategies against Fasciola infection in bovines.

Effect of heat stress on superoxide anion production in native and crossbred cattle under in vitro whole blood culture model

Impact of global warming on the dairy industry has gained attention due to huge economic losses through low production and fertility caused by heat stress. Exposure to hyperthermia provokes a series of complex responses in mammals which are been related to morphological and physiological alterations including the production of reactive oxygen species (ROS). A quantitative spectrophotometric based nitroblue tetrazolium (NBT) reduction assay was used to estimate the superoxide anion (•O₂^-) level in heat stressed (at 42 °C) whole blood cultures of native and crossbred bulls (Sahiwal and Frieswal), in vitro. The breed effect in the kinetics of •O₂^- production at different time periods of continual heat stress was analyzed by repeated measures ANOVA. Comparison between different time periods in reference to 37 °C was analyzed by paired t-test. The •O₂^- level was significantly different (p < 0.05) between cells at 37 °C and 42 °C at different periods of incubation. Kinetics study showed increment of •O₂^- production on the acute phase of stress followed by a reduction in both Sahiwal and Frieswal breeds. In Sahiwal breed, the inflated superoxide level continued abated till 4 h and raised again at 6 h, while in Frieswal •O₂^- level reverted to raise sooner with in 2 h of incubation itself. Contrarily, kinetic of •O₂^- level in plasma showed a significant reduction (p < 0.001) at 30 min of 42 °C incubation followed by increment of •O₂^- level. Further, the breed variation was significant (p < 0.05) and a significant high reduction of •O₂^- level was observed in Sahiwal breed. Our finding indicates that, a better and longer •O₂^- production homeostasis and higher plasma scavenging ability of native breed may be one of the reasons for the higher thermal tolerance of these breeds in tropical climate.

Prevalence of pathogenic trypanosomes in anaemic cattle from trypanosomosis challenged areas of Itezhi-tezhi district in central Zambia

BACKGROUND

The measure of anaemia status using packed cell volume (PCV) can be a reliable indicator of African trypanosomosis (AT) in the absence of other anaemia-causing conditions. However, studies that have estimated prevalence of anaemia in cattle from AT endemic areas have rarely reported the prevalence of the disease in the anaemic cattle. Therefore we investigated the prevalence of AT in anaemic cattle at sites that had recently reported the disease in Itezhi tezhi district of central Zambia.

METHODS

During a survey, blood samples were collected from 564 randomly selected cattle for anaemia determination from seven crush pens (Mutenda, Kapulwe, Banachoongo, Itumbi, Iyanda, New Ngoma and Shinampamba). At a PCV- value cut off of 26 %, all samples positive for anaemia were subjected to both parasitological examination on thick and thin blood smears and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for detection of trypanosome DNA. Fisher's exact test and a mixed effect logistic regression analyses were used to determine and measures associations, respectively.

RESULTS

Of 564 cattle screened, 58 (10.3 %; 95 % CI: 7.8-12.8 %) had anaemia. PCR-RFLP results showed that 17 (29.3 %; 95 % CI; 17.2-41.4 %) anaemic cattle were positive for pathogenic trypanosomes compared to 1 (1.7 %; 95 % CI: 0.0-5.2 %) on parasitological examination using thick smears. The infections were caused by Trypanosoma congolense and Trypanosoma vivax. Fisher's exact test showed a strong association between PCV and pathogenic trypanosome infection (P = 0.004). A mixed effect multivariate logistic regression showed that a one unit increase in PCV reduced the likelihood of detecting AT with PCR-RFLP by 24.7 % (95 % CI: 4.6-40.6 %; P = 0.019) in anaemic cattle, taking into account their age and sex, with random effects for crush pen.

CONCLUSION

These results suggest that T. congolense and T. vivax could be important causes of anaemia in cattle reared in AT endemic areas of Itezhi tezhi in Central Zambia. This also suggests that even though pathogenic trypanosomal infection was strongly associated with PCV, it could only account for up to 41 % of the anaemia in cattle. Therefore further investigation to ascertain other factors responsible for anaemia in AT endemic areas of Itezhi tezhi in Central Zambia is needed.

Variation and covariation in strongyle infection in East African shorthorn zebu calves

Parasite burden varies widely between individuals within a population, and can covary with multiple aspects of individual phenotype. Here we investigate the sources of variation in faecal strongyle eggs counts, and its association with body weight and a suite of haematological measures, in a cohort of indigenous zebu calves in Western Kenya, using relatedness matrices reconstructed from single nucleotide polymorphism (SNP) genotypes. Strongyle egg count was heritable (h² = 23·9%, s.e. = 11·8%) and we also found heritability of white blood cell counts (WBC) (h² = 27·6%, s.e. = 10·6%). All the traits investigated showed negative phenotypic covariances with strongyle egg count throughout the first year: high worm counts were associated with low values of WBC, red blood cell count, total serum protein and absolute eosinophil count. Furthermore, calf body weight at 1 week old was a significant predictor of strongyle EPG at 16–51 weeks, with smaller calves having a higher strongyle egg count later in life. Our results indicate a genetic basis to strongyle EPG in this population, and also reveal consistently strong negative associations between strongyle infection and other important aspects of the multivariate phenotype.

BRONSVOORT BMARK, COETZER JACOBUSA, HANDEL IANG, HANOTTE OLIVIER, JENNINGS AMY, LESOSKY MAIA, KIARA HENRY, THUMBI SAMM, TOYE PHIL, WOOLHOUSE MARKW, PENZHORN BANIEL. The impact of co-infections on the haematological profile of East African Short-horn Zebu calves

The cumulative effect of co-infections between pathogen pairs on the haematological response of East African Short-horn Zebu calves is described. Using a longitudinal study design a stratified clustered random sample of newborn calves were recruited into the Infectious Diseases of East African Livestock (IDEAL) study and monitored at 5-weekly intervals until 51 weeks of age. At each visit samples were collected and analysed to determine the infection status of each calf as well as their haematological response. The haematological parameters investigated included packed cell volume (PCV), white blood cell count (WBC) and platelet count (Plt). The pathogens of interest included tick-borne protozoa and rickettsias, trypanosomes and intestinal parasites. Generalized additive mixed-effect models were used to model the infectious status of pathogens against each haematological parameter, including significant interactions between pathogens. These models were further used to predict the cumulative effect of co-infecting pathogen pairs on each haematological parameter. The most significant decrease in PCV was found with co-infections of trypanosomes and strongyles. Strongyle infections also resulted in a significant decrease in WBC at a high infectious load. Trypanosomes were the major cause of thrombocytopenia. Platelet counts were also affected by interactions between tick-borne pathogens. Interactions between concomitant pathogens were found to complicate the prognosis and clinical presentation of infected calves and should be taken into consideration in any study that investigates disease under field conditions.