Resumen

D GALVIS, Rubén; AGUDELO, Diego  y  SAFFON, Andrés. Body Condition, lipoprotein profiles and ovarian activity in Holstein cows during early lactation. Rev Colom Cienc Pecua [online]. 2007, vol.20, n.1, pp.16-29. ISSN 0120-0690.

A group of 10 Holstein cows from Paysandú herd (Universidad Nacional de Colombia, sede Medellín), were evaluated at the expected calving day and over 10, 20, 30, 40 and 50 postpartum days, to determine body weight, BCS, milk yield and blood serum values of total cholesterol and lipoproteins (VLDL, LDL and HDL) in order to analyze the effect of Body Condition Score (BCS) at parturition on energy balance, weight loss, lipoprotein profiles and the ovarian activity in early postpartum.  Additionally, an ovarian ultrasonogram was performed to determinate follicle number and size, as well as the presence of corpora lutea. The composition of the diet was chemically analyzed monthly.  There were significant differences in body weight only at the interval between calving and 10 days postpartum; this was the period when the greatest weight loss was registered.  The energy balance (expressed as percentage of requirements) ranged between 3 to 18 % at parturition and from -22 to -9 % for the rest of the sampling times. Regarding lipid profiles, cholesterol, LDL and HDL showed statistically significant differences; these values increased proportionally to time after parturition.  Triglycerides and VLDL, on the other hand, increased until 40 days and decrease at 50 days postpartum.  There were no significant difference for the number of follicles throughout the experimental period, and only six cows ovulated. The group of cows that ovulated was able to maintain positive conditions for the use of body reserves, expressed in a greater BCS at parturition time, and a higher blood-serum HDL concentrations; however, these cows presented the major weight loss, the earliest nadir of energy balance and the higher blood-serum cholesterol concentrations. This would result in a better energy balance that effectively expressed itself a shorter time from parturition to ovulation and more milk production.

Palabras clave : energy balance; lipid profile; ovulation; tissue-reserve mobilization.

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