Impact of season on haematological and biochemical parameters of crossbred female calves in hot and humid tropics

The objective of the present study was to assess the impact of season on haematological and biochemical parameters of crossbred female calves. Seven crossbred female calves of 6–12 months of age were selected. The study was conducted in three different spells of 30 days each in pre-monsoon, monsoon and post-monsoon seasons. Ambient temperature (AT), relative humidity (RH) and temperature humidity index (THI) was recorded in all the three seasons. Whole blood was collected for estimation of haematological and plasma was used estimation of biochemical parameters. Highest AT and THI was recorded in pre-monsoon while highest RH was recorded in monsoon. The study revealed that season had no effect on haematological parameters such as total leucocyte, haemoglobin, packed cell volume, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, while total erythrocyte count was significantly lower in monsoon compared to pre and post-monsoon seasons. Glucose and cholesterol were significantly lower in pre-monsoon and monsoon compared to post-monsoon. Glutathione peroxidase activity was significantly higher in pre-monsoon compared to monsoon and post-monsoon. No significant difference between seasons in the concentration of total protein, albumin, globulin and albumin globulin ratio was noticed. The results indicate that hot conditions have profound effect on haematological and biochemical parameters of crossbred calves.     

Evaluation of Genetic Diversity,Population Structure,and Relationship Between Legendary Vechur Cattle and Crossbred Cattle of Kerala State,India

The legendary Vechur cattle of Kerala, described as a very short breed, and the crossbred (CB) Sunandini cattle population exhibited great phenotypic variation; hence, the present study attempted to analyze the genetic diversity existing between them. A set of 14 polymorphic microsatellites were chosen from FAO-ISAG panel and amplified from genomic DNA isolated from blood samples of 30 Vechur and 64 unrelated crossbred cattle, using fluorescent labeled primers. Both populations revealed high genetic diversity as evidenced from high observed number of alleles, Polymorphic Information Content and expected heterozygosity. Observed heterozygosity was lesser (0.699) than expected (0.752) in Vechur population which was further supported by positive F_IS value of 0.1149, indicating slight level of inbreeding in Vechur population. Overall, F_ST value was 0.065, which means genetic differentiation between crossbred and Vechur population was 6.5%, indicating that the crossbred cattle must have differentiated into a definite population that is different from the indigenous Vechur cows. Structure analysis indicated that the two populations showed distinct differences, with two underlying clusters. The present study supports the separation between Taurine and Zebu cattle and throws light onto the genetic diversity and relationship between native Vechur and crossbred cattle populations in Kerala state.     

Effects of different levels of ergot in concentrate on the health and performance of male calves

A number of studies dealing with the effects of ergot and ergot alkaloids on the health and performance of poultry and pigs were reported in the past, but only a few studies and field reports are available for ruminants. Therefore, a dose-response study was carried out with calves since young animals are considered to be especially sensitive to ergot. A total of 35 male Holstein calves were randomly assigned to three feeding groups after one month of feeding milk replacer. The mean initial live weight of the calves was 49.4±5.7 kg. One control group was fed an ergot-free concentrate (n=12), one group an ergot proportion of 1000 mg/kg in the concentrate (n=ll), and another group was fed a concentrate containing 5000 mg/kg ergot (n=12). Hay, grass silage and water were available forad libitum consumption, whereas the daily concentrate portion was restricted to 2 kg. Live weight, health parameters and feed intake were monitored over the experimental period of 84 days. In addition, blood samples were taken from theVena jugularis at the beginning and at the end of the experiment and analysed for ergot alkaloids and liver parameters. Total dry matter intake, live weight gain and feed-to-gain ratio were not significantly influenced by increasing ergot proportions when the whole experimental period was considered, although there was a trend for an ergot-related decrease in concentrate intake during the first 6 weeks of the experiment. After this period of time, it seemed that calves got used to the presence of ergot in the concentrate and were able to adjust their intake to the level of the control group. Moreover, health and liver parameters, such as total bilirubin, aspartate aminotransferase, glutamate dehydrogenase, gamma-glutamyl transpeptidase and creatine kinase in the serum were not significantly influenced by dietary treatments. Concentrations of the individual ergot alkaloids in serum were lower than the detection limits of the applied HPLC-method. In conclusion, it can be assumed that an ergot contamination of the concentrate up to 5000 mg/kg resulted in a transient depression of concentrate intake by the calves. However, no significant effects on health and performance could be detected when the entire test period of 84 days was considered. Presented at the 28^th Mykotoxin-Workshop, Bydgoszcz, Poland, May 29–31, 2006     

Evaluation of methodological and biological influences on the collection and composition of exhaled breath condensate

The purpose of this inter-species comparison (calves and pigs) was to identify methodological and biological influences on the collection and composition of exhaled breath condensate (EBC). A total of 352 EBC samples were collected, whilst variables of ventilation were registered in parallel. Partial pressure of carbon dioxide (pCO₂) and pH were analysed in non-degassed EBC samples. The concentration of total protein in EBC was measured colorimetrically. In both species, lung function was evaluated before and after EBC collection. Statistical analyses were performed to study the effect of EBC collection on lung function and to identify the influence of ventilatory variables on the collection and composition of EBC. Collection of EBC did not affect lung function. Despite the volume of EBC collected per unit time being primarily dependent on ventilation per unit time, species-specific conditions during the EBC collection process resulted in different dependences of EBC collection from other variables of ventilation (i.e. maximal airflow during expiration or expired tidal volume kg^-1 body weight). The concentration of protein ml^-1 EBC increased with the expired volume per min and with peak expiratory flow. Although the pCO₂ in fresh EBC was significantly negatively dependent on the duration of collection, comparable pHs (5.6 - 6.2) were measured in EBC of both calves and pigs. The obtained data may help one standardize EBC collection in different species.     

Plasma biomarker profiling in the detection of growth promoter use in calves

The detection of illicit growth promoter use during meat production within the European Union is reliant on residue testing which is a limiting factor on the number of animals which can be tested and consequently compromises the efficacy of testing procedures. The present study examined a novel detection strategy based on the profiling of plasma component concentrations in response to growth promoter administrations. Calves subjected to nortestosterone decanoate, 17β-oestradiol benzoate and dexamethasone were found to have altered urea, aminoterminal propeptide of type III procollagen and sex hormone binding globulin profiles in response to treatments. These findings demonstrate the potential of using the identification of perturbed profiles within a panel of biomarkers which cover a spectrum of biological activity to reveal growth promoter abuse.     

Survival and cause-specific mortality of moose calves in Northeastern Minnesota

Ungulate reproductive success (calf production and survival) influences population performance. The moose (Alces alces) population in northeastern Minnesota, USA, has declined 65% from 2006 to 2018 but has begun to stabilize. Because causes of this decline were largely unknown, we investigated production, survival, and cause-specific mortality of calves of the global positioning system (GPS)-collared females in this population. In 2013 and 2014, we GPS-collared 74 neonates and monitored them for survival. In 2015 and 2016, we monitored 50 and 35 calving females for signs of neonatal mortality using changes in adult female velocities and assessed seasonal calf survival by aerial surveys. In 2013 and 2014 (pooled), survival to 9 months was 0.34 (95% CI = 0.23–0.52) for collared calves, and in 2015 and 2016 (pooled) survival was 0.35 (95% CI = 0.26–0.48) for uncollared calves. Mortality in all 4 years was high during the first 50 days of life. In 2013 and 2014 (pooled), calving sites were relatively safe for collared neonates; predator-kills occurred a median 17.0 days after departure and a median 1,142 m from calving sites. Predation was the leading cause of death of collared calves (84% of mortalities), with wolves (Canis lupus) accounting for 77% of these. Other forms of mortality for collared and uncollared calves included drowning, infection, vehicle collision, and natural abandonment. We documented higher wolf predation than other recent studies with similar predator communities. Identifying specific causes of calf mortality and understanding their relations to various landscape characteristics and other extrinsic factors should yield insight into mechanisms contributing to the declining moose population in northeastern Minnesota and serve as a basis for ecologically sound management responses. © 2019 The Wildlife Society.     

Seasonal changes of gastrointestinal nematode populations in yearling beef cattle in Louisiana with emphasis on prevalence of inhibition in Ostertagia ostertagi

Investigation of seasonal changes in the composition of nematode populations, principally Ostertagia oslertagi, was conducted over 3 years at three locations in Louisiana. This is the most commonly occurring parasite of cattle in the state. Naturally infected yearling cattle were killed monthly over extended periods and tracer calves were grazed for monthly intervals from late autumn to summer at two locations in 1978–1979. Major objectives were to determine seasonal incidence of common gastrointestinal nematodes and for O. ostertagi, in particular, the time period during which larval inhibition was prevalent, circumstances under which larvae were conditioned to inhibition, and the duration of inhibition. Small numbers of inhibited O. ostertagi were recovered between November and February. Large numbers were found initially in March and increased numbers in April and May. Both normally developing and inhibition prone larvae were acquired during late winter-early spring, with the proportion of the latter being more prevalent in April and May. Evidence from tracer calves indicated that few O. ostertagi larvae were acquired after early June. Large burdens of inhibited larvae persisted in yearling cattle through summer; numbers of developing larvae and adults were minimal. Maturation of inhibited larvae occurs from August to October and in one instance was associated with cases of clinical parasitism. Factors responsible for inhibition were not defined, but increasing temperatures of late winter-early spring, host resistance, and density-dependence of populations were considered. Other abomasal genera were most prevalent in spring while intestinal genera were most common during autumn through spring.