Gabriele Gerardi

Use of serum amyloid A and milk amyloid A in the diagnosis of subclinical mastitis in dairy cows

Mastitis is the most frequent and costly disease in dairy herds, as it negatively affects yield and milk quality. The presence of clinical mastitis is quite easy to asses, whereas the diagnosis of the subclinical form can be more difficult and requires laboratory assays. Somatic cell count (SCC) is widely used as a rapid and low-cost indicator of mastitis, even if is not useful in discriminating between the clinical and subclinical form. As amyloid A has been investigated as a marker of mastitis, the aim of this study was to assess the potential value of measuring amyloid A in serum and milk and the correlation with SCC in the diagnosis of subclinical mastitis. The reliability of two different ELISA kits for the measurement of amyloid A in milk was also tested. During a 1-month trial period, 21 cows were assigned to three experimental groups according to their health status: 6 cows with clinical mastitis (CM), 10 cows with subclinical mastitis (SM) and 5 healthy cows (HE). Amyloid A was measured both in serum (SAA) and in quarter milk samples (mAA) with a serum ELISA kit, and in quarter milk samples (MAA) with a milk ELISA kit. SCC, total microbial count (TMC) and bacterial examination of the milk were also carried out. After a log transformation, the data were submitted to ANOVA and linear regression. TMC was significantly higher in cows with clinical mastitis, while no differences were observed between the other two experimental groups. SCC and MAA levels were significantly different among the three groups. mAA concentrations were similar between cows with subclinical and clinical mastitis, and SAA was not affected by mastitis. A significant correlation between SCC and MAA or mAA was detected, while no correlation was recorded between SAA and mAA. A close relationship between MAA and mAA was noticeable even at low concentrations, suggesting MAA as a potential physiological marker of subclinical mastitis.

The effects of different environmental conditions on thermoregulation and clinical and hematological variables in long-distance road-transported calves

The aim of this study was to investigate the effects of long-distance road transport (19 h, from Poland to Italy) during 2 seasons (summer vs. winter) on clinical and hematological variables in calves. The environmental temperature range that could compromise the thermoregulation system (thermal stress) of the calves was tested. For the 7 Holstein calves in each transport, the BW and rectal temperature (RT) were measured, and blood samples were collected at the farm of origin, before loading at the transit center (T2), after unloading at the farm of destination (T3), and 1, 2, 3, and 4 d after arrival. The body temperature (BT) and heart rate (HR) were continuously monitored from T2 to T3. The data were statistically analyzed according to a mixed model that considered the fixed effects of transport (repeated measurements), season of journey, and their interaction. Within the observed temperature-humidity index (THI) range (30 to 80), effective thermoregulation allowed the calves to maintain their BT with small physiologic changes to prevent thermal stress, particularly in the summer. With no seasonal differences, the HR was greater at loading than unloading (120 vs. 115 beats per min; P = 0.012). As for the transport effect, the BW was less (P < 0.001) after unloading, and the RT was greater (P = 0.004). This effect was more marked in summer. The hematological variables indicated a moderate effect of transport on the hydration condition, reactive and muscular systems, and metabolism, although hematocrit (P = 0.004), erythrocytes, cortisol, NEFA, β-hydroxybutyrate, lactate, creatine kinase, lactate dehydrogenase, and aspartate aminotransferase activity (P < 0.001), and total protein (P = 0.007) were greater after unloading. This was confirmed by a moderate decrease in total leukocytes (P = 0.031) and glucose concentration (P = 0.002). The changes in the clinical variables were similar for both seasons even though in the summer, hematocrit (P < 0.001), urea (P = 0.008), and total protein (P = 0.010) increased and glucose concentration (P = 0.038) decreased. In conclusion, the data did not show a pronounced effect attributable to the season of the journey. Long-distance road transport leads to notable changes in clinical and hematological variables at the end of the journey. However, these variables remained within their physiological ranges and returned to basal values within a few days after the journey.

Two-dimensional, M-mode and Doppler-derived echocardiographic parameters in sedated healthy growing female sheep:

Despite the fact that sheep are a widely used animal model in cardiovascular research, reference values for transthoracic echocardiography in normal growing animals are not available. Eight healthy female lambs underwent two-dimensional, M-mode and pulsed wave Doppler echocardiographic examination at 100 days of age and every three months thereafter over a 12-month period. The study was conducted under sedation with midazolam, butorphanol and constant rate infusion of intravenous propofol. Their growth phase was completed at about one year of age. All the echocardiographic parameters considered were significantly correlated with body weight and age class except for the left ventricular systolic and diastolic diameters. Functional indices were not correlated to body weight or age except for the E-point to septal separation distance (EPSS). Doppler-derived parameters were not influenced by independent variables. Transthoracic echocardiography can be considered an applicable method for cardiovascular research using a growing lamb animal model after appropriate adjustments for age and body size.

Relationship between milk fatty acid composition and dietary roughage source in dairy cows

According to a 2 × 2 crossover design, 14 Holstein dairy cows were fed two isoenergetic diets based on either grass hay (GH) or maize silage (MS). Milk samples were collected during the third week of each period, and fatty acid (FA) profiles were analyzed using gas chromatography. The data obtained were subjected to ANOVA. Dietary treatment had no effect on either dry matter intake or milk yield. Milk from animals fed the GH-diet contained lower concentrations of saturated FAs (61.9 vs. 63.4% of total FAs; P < 0.05) and higher levels of polyunsaturated FAs (PUFAs) (6.1 vs. 5.8; P < 0.01). Feeding additional hay also increased conjugated linoleic acid and n-3 FA levels and decreased C16:0 levels. Increases in both PUFAs and n-3 FAs resulted in lower (P < 0.01) atherogenic and thrombogenic indices in milk from animals fed the GH diet compared with those fed the MS diet. A complete substitution of GH for MS appeared to improve milk FA profiles, even using different types of concentrates to provide a balanced diet.

Interference of haemolysis and hyperproteinemia on Sodium, Potassium, and Chloride measurements in canine serum samples

Interference of haemolysis and hyperproteinemia on Sodium, Potassium, and Chloride measurements in canine serum samples D. Bernardini & G. Gerardi & B. Contiero & M. Caldin Published online: 28 July 2009 # Springer Science + Business Media B.V. 2009

Lecithin: a by-product of biodiesel production and a source of choline for dairy cows

The aim of the present study was to compare soy lecithins (L), a by-product of the biodiesel production process, with choline chloride microencapsulated with hydrogenated vegetable oils (C), to verify their effects on dry matter intake, milk yield, milk quality traits, milk choline and haematological profile of dairy cows. A total of 12 mid-lactating Holstein Friesian cows were assigned to one of two experimental groups and fed according to cross-over design (2 diets × 2 periods). Diets were isoenergetic, isofibrous and isonitrogenous and had the same content of choline. Dry matter intake, milk yield and the 3.5% fat-corrected milk (FCM) were not affected by the diet. The milk choline content and the milk quality did not differ between treatments, with the exception of milk fat (P<0.05) and urea (P<0.01), which resulted lower for the L-group. Milk fat, protein and choline yields remained unaffected. With regard to the haematological profile, all of the parameters fell within the physiological range of lactating dairy cows, and the only difference was represented by the lower urea level of the L fed cows (P<0.01), that could be explained by a better N metabolic efficiency. Results indicated that soy lecithins can be used as an available source of choline in midlactating dairy cows.

Aortic stenting in the growing sheep causes aortic endothelial dysfunction but not hypertension: Clinical implications for coarctation repair

BACKGROUND Stent implantation is the treatment of choice for adolescents and adults with aortic coarctation (CoAo). Despite excellent short-term results, 20%-40% of the patients develop arterial hypertension later in life, which was attributed to inappropriate response of the aortic baroreceptors to increased stiffness of the ascending aorta (ASAO), either congenital or induced by CoAo repair. In particular, it has been hypothesized that stent itself may cause or sustain hypertension. Therefore, we aimed to study the hemodynamic and structural impact following stent implantation in the normal aorta of a growing animal. METHODS Eight female sheep completed the study and a stent was implanted in four. Every 3 mo we measured blood pressure of the anterior and posterior limbs and left ventricular function by echocardiography. Twelve months later invasive pressure was measured under baseline and simulated stress conditions. Expression of genes indicating oxidative stress (OS), endothelial dysfunction (ED) and stiffness, as well as pathological examination were performed in ascending (ASAO) and descending aorta (DSAO). RESULTS SOD1 and MMP9 gene expression were higher in ASAO of the stented animals, compared to DSAO and controls, while NOS3 was decreased. No differences were found in blood pressure and echocardiographic parameters. No histological differences were found in the aorta of the two groups of animals. CONCLUSIONS Stent does not affect central and peripheral hemodynamics, cardiac structure and function even in the long term. However, the finding of markers of OS and increased stiffness of ASAO, proximal to the stent, points to molecular mechanisms for increased cardiovascular risk of patients with stented CoAo.

Changes in the Metabolic Profile and Performance of Dairy Cows Fed Two Dietary Crude Protein Concentrations

According to a 2 × 2 cross-over design, 14 lactating Holstein–Friesian cows were fed two isofibrous and isoenergetic diets based on either 14.5 % of crude protein (LOW CP diet) or 16.5 % (HIGH CP diet). Milk yield and quality and metabolic profile were detected during the third week of each experimental period. Dietary treatment had no effect on dry matter (DM) intake (21.0 kg/d on average), milk yield (34.7 kg/d on average), and milk protein content (3.48 % on average). LOW CP fed cows showed a lower milk urea content (19.4 vs. 29.7 mg/dl; P < 0.01). In LOW CP treatment, it was observed a significant increase of plasma globulins, glucose, and creatinine meanwhile the urea level was significant lower. The efficiency of CP utilization was higher (0.39 vs. 0.34; P < 0.05) for the LOW CP group.

Effects of Ambient Temperature on Calf Welfare Parameters During Long-Road Transportation

In the tested ambient temperature range (i.e., between −7 and 30°C), it was asserted that calves physical regulatory system of temperature homeostasis regularly works, particularly under ambient winter conditions. In summer, only ambient temperatures near 31°C could lead to reduced operation of the thermoregulatory center with the presence of clinical signs. This finding is strengthened by the correlation between ambient and rectal temperatures (R 2=0.57; P<0.001); rectal temperature appears to remain constant within an ambient temperature range between 8°C and 28°C. Furthermore, ambient temperatures lower than −7°C cause a slight reduction in body temperature, while values higher than 29°C result in a more than proportional physical temperature increase, which are better interpolated using a polynomial equation.