Thyroid hormones, blood plasma metabolites and haematological parameters in relationship to milk yield in dairy cows

Abstract

To study their relationship to milk yield, the concentrations, in jugular venous blood, of thyroxine iodine (T 4 I), thyroxine (T 4 ), 3,5,3'-tri-iodothyronine (T 3 ), glucose, non-esterified fatty acids (NEFA), triglycerides, phospholipids, cholesterol, total protein, albumin, urea, haemoglobin and packed cell volume (PCV) have been measured in 36 cows (Simmental, Swiss Brown, Holstein and Simmental x Holstein) of different ages during a full lactation, pregnancy, dry period, parturition and 150 days of the ensuing lactation. Thyroid hormones and triglycerides were negatively, and total protein, globulin, cholesterol and phospholipids were positively, correlated with uncorrected or corrected milk yield during several periods of lactation, whereas glucose, NEFA, albumin, urea, haemoglobin and packed cell volume were not correlated with milk yield. The 10 animals with the highest milk yield (18-9 to 23-5 kg/day) exhibited significantly lower values of T 4 I, T 4 , T 3 and glucose, significantly higher levels of total protein and globulin and tended to have higher levels of NEFA than the 10 cows with the lowest milk yield (10-9 to 14-3 kg/day) throughout or during certain periods of lactation, whereas concentrations of triglycerides, phospholipids, cholesterol, albumin, haemoglobin and PCV did not differ. Changes in T 4 I, T 4 , T 3 , glucose and total jprotein during lactation were also influenced by age, presumably associated with an increase in milk production with age. T 3 was consistently lowest and cholesterol and phospholipids, during later stages of lactation, were highest in Holsteins, which had the highest milk yields of all breeds. Changes of blood parameters were mainly caused by shifts in energy and protein metabolism in association with level of milk production.

Effects of different energy intakes before and after calving on food intake, performance and blood hormones and metabolites in dairy cows

“…Because free fractions remained constant during the experiment and were similar in the three groups, blood plasma binding capacities were not altered and measurements of total T 4 therefore represented changes in the concentration of free T 4 . In accordance with previous studies (Blum et al, 1979(Blum et al, , 1980(Blum et al, , 1983a, T 4 was lowered by marked energy deficiency.…”

“…The according to requirements before parturition decrease of glucose after parturition was was presumably facilitated by low circulating insulin and by high circulating GH. The pattern of NEFA before, during and after parturition has already been noted (Radloff and Schultz, 1967;Seidel, Pufe, Mueller, Gruen, Kolb and Schuhmacher, 1973;Blum et al, 1983a). Circulating NEFA after parturition reflected differences in energy supply between groups.…”

“…The changes in total T 4 during the dry period, pregnancy and lactation have recently been described (Blum et al, 1983a). Because free fractions remained constant during the experiment and were similar in the three groups, blood plasma binding capacities were not altered and measurements of total T 4 therefore represented changes in the concentration of free T 4 .…”

“…Concentrations (Blum, Gingins, Vitins and Bickel, 1980;Blum, Kunz, Bachmann and Colombo, 1981;Blum, Kunz and Frohli, 1982;Blum, Kunz, Leuenberger, Gautschi and Keller, 1983a). GH was measured according to the method of Hart, Flux, Andrews and McNeilly (1975).…”

Revue bibliographique : Variations quantitatives et métabolisme des lipides dans les tissus adipeux et le foie au cours du cycle gestation-lactation 2e partie : chez la brebis et la vache

“…Ces activités augmentent à nouveau après le pic de lactation (Baldwin et al, 1973 ;Shirley, 1973 ;Grichting et al, 1977a, b ;Keys et Capuco, 1985 ;Mc Farland et Mc Namara, 1985 ; Reid et al, 1986), en particulier chez les animaux qui ont plus fortement mobilisé leurs lipides en début de lactation ( fig. 6 et 8), ou chez les faibles productrices (Mc Namara et al, 1985 Journet, 1967 ;Pehrson, 1971 ;Henseler et al, 1973 ;Metz et al, 1973 ;Rémond et al, 1973 ;Grigsby et al, 1974 ;Luthman et Persson, 1975 ;Schwalm et Schultz, 1976 ;Blum et al, 1983 ;Pethes et al, 19851. Les teneurs en AGNE sanguins sont en partie liées au poids des veaux, à la diminution du niveau d7ngestion volontaire et au bilan énergétique des mères (Petit et Rémond, 1977 ;Bernal-Santos, 1982 ;Chilliard et al, 1982, fig. 8 ; Doreau, 1983 ; Wright, 1983 ;Larnicol et al, 1984 ;.…”