Veterinar, Vol. 56. No. 1., 2018.
Izvorni znanstveni članak
Comparison of the LH wave characteristics in dairy cows subjected to three synchronization protocols
Antonia Bem
; Veterinarski fakultet Sveučilišta u Zagrebu, Zagreb, Hrvatska
Dina Jelenčić
; Veterinarski fakultet Sveučilišta u Zagrebu, Zagreb, Hrvatska
Goran Štibrić
; farma mliječnih krava
Josipa Kuleš
; Veterinarski fakultet Sveučilišta u Zagrebu, Zagreb, Hrvatska
Renata Barić Rafaj
; Veterinarski fakultet Sveučilišta u Zagrebu, Zagreb, Hrvatska
Juraj Grizelj
; Veterinarski fakultet Sveučilišta u Zagrebu, Zagreb, Hrvatska
Silvijo Vince
; Veterinarski fakultet Sveučilišta u Zagrebu, Zagreb, Hrvatska
Branimira Špoljarić
; Veterinarski fakultet Sveučilišta u Zagrebu, Zagreb, Hrvatska
Daniel Špoljarić
; Veterinarski fakultet Sveučilišta u Zagrebu, Zagreb, Hrvatska
Sažetak
Fertility of high-yielding dairy cows can be improved by use of controlled reproduction methods at the beginning of breeding. Despite precise technology and long-term experience in induction-synchronization protocols, little is known about characteristics of LH pulse wave. The goal of this research was to determine characteristics of LH waves in cows subjected to different synchronization protocols with timed artificial insemination (TAI). The archive data from the research on 60 Holstein-Friesian breeds, in early lactation, were used. Cows were divided into three groups: group A was subjected to modified Double Ovsynch (DO), group B modified Presynch (PS), while group C was subjected to Ovsynch (OV) protocol. Blood samples were taken from animals to determine LH (n=15) and progesterone (n=60). All cows were artificially inseminated at 6 and 24 hours after the second injection of GnRH. In group B, percentage of pregnant cows 30 days after TAI was higher (P <0.10) than in cows from the other two groups (B: A: C = 47.37%: 29.41%: 21.05%). The decrease in the percentage of pregnant cows 60 days after TAI was more pronounced in group B (47.36%: 31.58%) and milder in group C (21.05%: 15.79%), suggesting that prevalence of late embryonic and foetal mortality may be higher in PS and OV protocols compared to DO protocol. Only cows from group A (P <0.001) had the dominant follicle of optimal size, while in the other two groups the diameter significantly exceeded that value. Progesterone concentration was strongly grouped after the PGF2α application in all three protocols, with values below the 0.5 ng/mL in more than 50 % of animals. There was significant (P <0.01) difference between LH on zero hours between group C (6.12 ± 1.16 ng/mL) and B (1.84 ± 1.16 ng/mL). Four hours later, the level of LH in group A significantly deviates in relation to groups B and C (P <0.01), whereas cows from group C still have the highest concentration of LH. Ovulation was ultrasonically confirmed in all cows, except for one from group C, which was later culled.
Ključne riječi
dairy cows; synchronization; ovulation; LH; progesterone
Hrčak ID:
200316
URI
Datum izdavanja:
20.4.2018.
Posjeta: 790 *