Authors:B. Bényei, Margit Kulcsár, A. Gáspárdy, and Anna Pécsi
Changes of progesterone (P4) profiles and oestrous cycle were investigated up to 70 days in 20 superovulated Holstein-Friesian cows in a dry tropical environment (Brazil). Superovulated cows showed no significant differences in relation to P4 level at the time of embryo recovery (39.0 ± 27.1 nmol/L, P = 0.536), first and second (12.0 ± 6.0 and 10.7 ± 2.2 nmol/L, P = 0.543) cycle. There was a close correlation between serum P4 concentration and the number of corpora lutea (CL; 13.3 ± 9.5) at the recovery (P < 0.0001). After the embryo collection, cows returned to cycle in different ways: (i) group of donors returning to cycle after 2.2 ± 0.8 days, (ii) group with a delay of 11.0 ± 1.9 days; and (iii) animals having a long (28.8 ± 2.2 days) acyclic period, which is significant (P < 0.001). The remaining animals (30%) showed cystic ovarian malformations. P4 level at the time of embryo recovery does not influence the oestrous cycle changes. The results suggest that Holstein-Friesian donor cows may suffer from cystic ovarian degeneration and may have a long acyclic period after superovulatory treatment in a tropical climate.
Authors:Balázs Bényei, István Komlósi, Anna Pécsi, Margit Kulcsár, László Huzsvai, C. Barros, and Gyula Huszenicza
Metabolic hormones [insulin, leptin, insulin-like growth factor-I (IGF-I), thyroxine (T4) and triiodothyronine (T3)], progesterone (P4) and beta-hydroxybutyrate (BHB) serum concentrations were evaluated and their effect on the superovulation results of donor cows was investigated in a semi-arid environment. Body weight, body condition score (BCS) and lactation stage were also included in the analysis. Twenty-three Holstein-Friesian cows were superovulated with 600 IU FSHp following the routine procedure and flushed on day 7 in a Multiple Ovulation and Embryo Transfer Centre in the semi-arid area of Brazil. The corpora lutea (CL) were counted and blood samples were collected for assays. All of the hormones investigated and BHB serum concentrations were within the physiological ranges. There was a positive correlation between hormones, except between BHB and all the others. The leptin level was influenced by feeding status, as indicated by the BCS. Insulin, T4, T3 and BHB levels were affected by milking status. Dry cows had higher levels of all hormones except BHB. An optimum level of leptin resulted in the highest number of CL, while the linear increase of P4, T4 and IGF significantly increased the number of CL.