Characterization of some parameters of non-specific immunity in dairy cattle (I)

Assessment of blood and productive parameters in mid-lactation dairy cows fed different diets: replacement of corn silage with triticale silage

Corn crops require large amounts of resources that affect the environmental sustainability of dairy cow farming systems. The aim of the study was thus to investigate the effects of the replacement of corn silage (CS) with triticale silage (TS) by evaluating blood and productive parameters. The study lasted 7 weeks and involved two groups of 20 Italian Holstein Friesian dairy cows that were homogeneous in terms of parity (3±1.5), days in milk (DIM) (150±85.0), and daily milk production (26±4.6 kg).

Chemical analysis of feeds was carried out weekly. Dry-matter intake was estimated daily. At the beginning and end of the trial, haematological, metabolic, and immunological parameters were analysed. At the same, time body weight and body condition score were measured. Milk characteristics were also analysed weekly. Statistical analysis was performed by ANOVA on data of the second sampling, and a non-parametric test was performed to analyse BCS.

Regarding the haematological parameters in the two groups, only lymphocyte values were not in the normal range (2.86 and 2.50×109 L for CS and TS, respectively). Metabolic parameters were in the normal range except for blood ureic nitrogen (BUN; 13.65 and 14.04 mgdL-1), non-esterified fatty acids (NEFAs; 21.40 and 31.93 µmolL-1), and Cl (91.99 and 93.50 mmolL-1). Hair cortisol was low (0.94 and 0.91 pgmg-1), indicating the absence of stress signs, as confirmed by the results of other immunological parameters (serum lysozyme (SL), bactericidal activity (SBA), haptoglobin (HP), and oxygen free radicals (OFRs)).

Statistical differences were not found either for haematological or biochemical parameters. The total replacement of CS with TS did not affect milk yield and composition.

In conclusion, the replacement of CS by TS did not give rise to significant modifications in the parameters investigated and did not alter the health status of the animals, thus suggesting the feasibility of its introduction into the diet of mid-lactation dairy cows.

Welfare Assessment: Correspondence Analysis of Welfare Score and Hematological and Biochemical Profiles of Dairy Cows in Sardinia, Italy

The need for animal welfare definition and assessment is increasing worldwide, and several studies have been conducted to help fill the knowledge gaps regarding the welfare of cattle. However, further studies are needed to provide valid synthetized measures for welfare evaluation. The aim of this study was to assess the welfare status of 16 Sardinian dairy cattle farms, based on the developed Animal Welfare and Biosecurity Evaluation checklist (AWB-EF) and the corresponding hematological, biochemical, and electrophoretic profiles of these animals. Considering the AWB-EF as gold standard, blood samples were collected from 230 Holstein breed dairy cattle, aged between 3 and 8 years, out of the periparturient period, and with no clinical signs of specific pathologies. Principal Component (PC) and correlation analyses were performed to simplify phenomena interpretation and assess positive/negative associations. Four PCs were able to explain 76% of the total variability, and six laboratory parameters were strongly associated with the AWB-EF score (Spearman's correlation coefficient ≥ 0.40, p-Value < 0.05), reflecting the real health status of the animals. Given the complexity of animal welfare as a multidimensional concept and the need to include both animal-based and non-based measures in welfare evaluation, the present work represents a sound basis for future evaluation and veterinary health planning.

Bold personality makes domestic dogs entering a shelter less vulnerable to diseases

It is widely recognised that for vertebrate species, personalities vary along an axis with extremes represented by ‘proactive’ and ‘reactive‘ individuals. The aim of this study was to verify whether there is a relationship between personality and disease vulnerability in domestic dogs (Canis familiaris) exposed to an intensely stressful situation such as entering a shelter. Twenty-eight shelter dogs participated in the study. The ethogram consisted of approximately 100 behavioural patterns. Behavioural observations of dogs in their new environment, a Novel Object and a T-maze test were used to evaluate the personality of the dogs captured as strays and entering the shelter. A blood sample from each dog was obtained at admission into the shelter and after a month to evaluate their immunological state. Based on PCA analyses of observational combined with experimental data, the dogs were ordered along the boldness-shyness axis, with the first being the boldest. Excluding one (the 6th), the first 10 dogs showed an improved health status: absence of disease symptoms during the 30 days of monitoring and improved immunological parameters; the opposite was found for shy dogs. The results of this research seem to confirm findings in other vertebrate species, i.e., bold and shy dog vulnerability to diseases might be different, especially when they must cope with a stressful and highly infectious environment such as a dog shelter.

An immunological approach to the evaluation of welfare in Holstein Frisian cattle

Clinical immunological and haematological parameters, along with clinical conditions and growth rate, were studied in 413 male Holstein Frisian calves introduced into a large centre for genetic selection in different seasons of the year. Abnormalities were revealed by the laboratory tests in the great majority of calves after transportation stress, a general tendency to the restoration of physiological values being evident thereafter. Laboratory parameters were highly correlated with disease conditions: with three exceptions only, animals showed altered laboratory parameters some days before the occurrence of clinical symptoms. Eighteen per cent of animals showed altered laboratory parameters with no obvious clinical signs of disease; yet they experienced a reduced weight gain. Results suggest that clinical immunological and haematological parameters could be the foundation of a new, large-scale, robust approach to the control of welfare in cattle, which should be integrated preferably by a further range of records and measures.

Comparative evaluation of specific vaccines and immuno-modulators in disease control of beef cattle

Two field trials were undertaken to evaluate specific vaccines and Biological Response Modifiers (B.R.M.) with regard to disease control of beef cattle. Clinical data and laboratory results strongly suggested a genetically determined resistance to transportation stress of some cattle breeds, with possible important consequences on the occurrence of multi-factor diseases. Plenty of calves showed detectable levels of serum interferon and a remarkable activation of at least some lymphocyte populations in the first days after arrival. In general, B.R.M.-treated cattle could better react against environmental pathogens, as evidenced by both clinical and laboratory findings. Several data emerged that even the efficacy of specific vaccines could be largely accounted for by a positive modulation of non-specific immunity; this latter feature can be mainly referred to adjuvants and/or some bacterial antigens.

Postnatal changes in lymphocyte function of dairy calves

Lymphocyte blastogenic response, B-lymphocyte population and antibody-producing activity of lymphocytes were determined to evaluate the lymphocyte function in neonatal calves during the first 4 weeks of life. The mean percentage of B-lymphocytes ranged from 10.2 to 12.5% during the first 14 days of life and from 15.3 to 17.5% in calves from the day 21 to day 28 after birth. The absolute number of B-lymphocytes increased significantly (P less than 0.05) from 370/microliters at birth to 736/microliters on day 28 after birth. The mean stimulation index of blastogenic response, measured by fluorometric assay, ranged from 5.75 to 6.61 with Con A, from 5.29 to 5.98 with PHA and from 1.89 to 2.50 with PWM. The mean (+/- S.D.) number of plaque forming cells ranged from 22.0 (+/- 12.0) to 24.7 (+/- 9.2) in cultured lymphocytes from 5 calves at birth to 14 days after birth and their levels increased markedly from 137.8 (+/- 88.3) to 162.0 (+/- 57.8) in lymphocytes from 20 days to 28 days after birth. The present study showed that antibody-producing activity of lymphocytes is lower in calves within 3 weeks after birth compared to that of calves 3 weeks after birth, indicating that neonatal calf lymphocytes have a low antibody-producing activity at least up to 1 month after birth.

Characterization of some parameters of non-specific immunity in beef cattle (II)

Serum protein, immunoglobulins, complement, lysozyme, serum bactericidal activity and blast transformation of peripheral blood lymphocytes were tested in beef cattle in different herds and age groups. These parameters were evaluated in their time-kinetics, in comparison with age-matched groups of dairy cattle. Like dairy calves, beef calves up to 4 months of age were shown to have low levels of serum bactericidal activity and haemolytic complement; besides, a worse profile was detected in serum protein and gamma 2 globulin levels. Al(OH)3 and oil-adjuvanted vaccines had a favourable influence on immunoglobulin and lysozyme synthesis. An acute stressing event like transportation was shown to decrease mitogen-driven lymphocyte stimulation for at least 10 days after arrival.