D Alberghina | PubMed Health

PubMed2005

Effect of long-distance road transport on thyroid and adrenal function and haematocrit values in Limousin cattle: influence of body weight decrease.

The purpose of this study was to evaluate the effect of long-distance road transport as a relevant stressor on total and free iodothyronines, cortisol levels and haematocrit values in 10 male Limousin cattle. Serum T3,T4,fT3,fT4 and cortisol concentrations were analysed by immunoenzymatic assays. Serum cortisol levels and haematocrit modifications were also evaluated on the basis of percentage body weight decrease. The results showed a general increase of total and free iodothyronines and cortisol levels after short-and long-distance road transport and a decrease 15 days after transport, as compared to basal values. Significant positive correlations between T3 and T4, between T3 and fT3, and between T4 and fT4 were found. These results suggest that transport stress induces an increase in the activity of thyroid and adrenal function in Limousin cattle that is evident after even a short-distance road transport and continues to increase after long-distance transport.

Adrenal Glands↗

PubMed2002

A lactate-guided conditioning programme to improve endurance performance.

Blood lactate measurements are used widely in horses to assess athletic performance, but there are few published data on using lactate as a guide for endurance improvement. The velocity at which blood lactate concentration ([LA]) of 4 mmol/l is reached (v4) is widely used to determine fitness. In an earlier study of v4, exercise at low intensities for longer duration was more effective at improving endurance than shorter, higher intensities. However, the prescription was unchanged during the study (6 weeks). We hypothesised that, to produce greater improvement in v4 in the same time frame, it is necessary to adjust conditioning regimes more frequently. Six horses underwent an initial treadmill-based standard exercise test (SET). A regression analysis [LA]-speed relationship was used to calculate v2. Horses were then conditioned for 45 min at their calculated v2 3 times/week (6% incline). Every 2 weeks the horses performed an SET to evaluate the v2 conditioning protocol which ended with SET 4. Mean v4 increased 17% from SET 1 to SET 4 (P = 0.003; 5.8 +/- 03 to 6.8 +/- 0.4 m/s). This study demonstrates that a lactate-guided conditioning programme can significantly enhance endurance performance over a 6-week time peroid when the conditioning protocol is adjusted every 2 weeks based on v4 improvement.

Animals↗