Antral follicle count, productive and reproductive parameters in Bos indicus and Bos indicus-taurus prepubertal heifers with early puberty induction

Abstract

Prepubertal Nelore (G-N = 15) and crossbred Nelore x Aberdeen Angus heifers (G-NA = 15) were used for this study. AFC, live weight, body condition score (BCS), ovary and dominant follicle (DF) diameters were determined in each animal. Puberty induction was performed by insertion of a 4th use progesterone device (D0) which was removed on D12. Also, 1 mg estradiol benzoate was administered, and estrus intensity was classified (D12). At D21, the presence and diameter of the corpus luteum (CL) were registered. AFC was highly repeatable, regardless of hormone induction in both G-N (r=0.79) and G-NA (r=0.90). The mean AFC was greater in G-N compared to G-NA (24.2±8.5 vs. 17.7±9.0 follicles). A variation in BCS throughout the study occurred in G-NA, but not in G-N. The average weight gain (AWG) was greater in G-NA compared to G-N (0.69±0.33 vs. 0.40±0.29kg/day). The G-NA resulted in a larger diameter of DF at D12 than G-N (11.6±2.7 vs. 9.3±1.5mm). In conclusion, AFC was greater in Nelore heifers, although in both breeds this count was highly repeatable during puberty induction. Crossbred heifers had greater BCS and AWG with greater diameter of DF, indicating higher precocity when compared to Nelore heifers.

Características de las ondas de desarrollo folicular en vaquillas prepúberes Bos taurus indicus de dos tallas diferentes

“…Una de las mayores limitantes de productividad del ganado en zonas tropicales, lo constituye el inicio tardío de la pubertad y al primer parto. A pesar de la edad avanzada al que las vaquillas Bos taurus indicus comienzan su vida productiva, se han reportado múltiples estudios afirmando un mayor reclutamiento folicular por parte del ganado Cebú en comparación con el ganado Bos taurus taurus (Delchiaro et al, 2022). Entender las diferencias existentes entre las razas bovinas es importante para poder establecer un correcto manejo de los procedimientos o tecnologías reproductivas que se utilizan en la actualidad (Viana et al, 2000).…”

Serum Follicular Fluid Growth Differentiation Factor 9 (GDF-9) and Bone Morphogenic Protein 15 (BMP-15) as Markers of Ovarian Reserve

“…Antral follicle count (AFC) is defined as the sum of the number of small antral follicles in both female ovaries during the 2nd to 4th days of the menstrual cycle. AFC is calculated using trans-vaginal ultrasound (TVUS) [10]. The follicular diameter that is used to define AFC is 2-8 mm [11].…”