Optimisation of Early Pregnancy Diagnosis and Resynchronisation in Beef Cows.

The objectives of this study were (1) to investigate the effects of the preovulatory follicle (POF) size on the accuracy of Doppler-based early pregnancy detection, and (2) to determine whether the removal of PGF2α (PGF) treatment during the resynchronisation protocol would affect fertility in beef cows. In Experiment 1, Nelore suckling cows (n = 224) were enrolled in an estradiol-progesterone-based timed artificial insemination (TAI) protocol. At TAI, cows were separated based on the range of POF diameters, as follows: ≤11.

Selecting oocyte donors based on anti-Müllerian hormone (AMH) concentrations: A critical analysis of using cutoff values as exclusion criterion for an in vitro embryo production program in Gir cattle.

The aims of this study were to determine anti-müllerian hormone (AMH) cutoff values for selecting Gir (Bos taurus indicus) oocyte donors and estimate the impact of using AMH concentrations as a selection criterion. In Exp. 1, Gir heifers (n=120) were sampled for AMH analysis and submitted to ovum pick-up and in vitro embryo production (OPU-IVEP).

Does GnRH treatment at TAI regardless of estrus occurrence increase pregnancy rate in crossbred suckled cows?

The impact of GnRH treatment on the day of TAI in beef cows has received limited investigation, especially concerning its association with estrus expression. Consequently, two experiments were conducted to assess the potential of GnRH treatment on the day of TAI to enhance fertility according to the expression or not of estrus in beef cows. Experiment 1 aimed to determine ovulation rate and luteal function, while Experiment 2 aimed to determine the effect of the two GnRH treatment approaches on pregnancy rate.

Exploring uterine inflammation in postpartum primiparous precocious and conventional and multiparous Bos indicus beef cows.

This study aimed to compare the postpartum uterine dynamics of primiparous precocious (PP), primiparous conventional (PC) and multiparous conventional (MC) Bos indicus beef cows. For this purpose, PP (n = 8), PC (n = 18) and MC (n = 12) cows were enrolled in this study. These cows were evaluated at 20 and 10 days prepartum and weekly from parturition to 42 days postpartum (DPP).

Early versus late body condition score loss in dairy cows: Reproductive performance.

This study aimed to compare milk production and reproductive performance in high yield Holstein cows that lose BCS early and late in the postpartum period. Lactating dairy cows (n = 76) were received first timed AI at 60 to 75 DIM using the farm-managed estradiol-progesterone-GnRH-based timed AI protocol. The BCS of all cows was daily evaluated by automated BCS cameras.

Does combining estradiol cypionate and GnRH for ovulation induction in recipient cows increase pregnancy rate after timed embryo transfer?

Estradiol cypionate (EC) or GnRH have been widely used for ovulation induction in timed embryo transfer (TET). EC administration increases the proportion of cows that show estrus, whereas GnRH promotes more synchronized ovulations. The aim of the present study was to evaluate the potential beneficial effects of combining EC and GnRH in TET.

Effect of calving to timed artificial insemination interval on fertility of beef cows.

The objectives of this study were to determine the effect of calving to timed artificial insemination (C-TAI) interval on fertility of Bos taurus and Bos indicus cows and to determine the best C-TAI interval to include postpartum cows in TAI programs in each genotype (B. taurus and B. indicus).

Prostaglandin F2α regulation and function during ovulation and luteinization in cows.

Although prostaglandins are important in the ovulation process, a precise role for prostaglandin F2α (PGF) has not been elucidated. This study aimed to evaluate the regulation of PGF receptor mRNA (PTGFR) in granulosa cells and the local effect of PGF on ovulation and luteinization. In Experiment 1, using samples collected in vivo before (Day 2), during (Day 3) and after (Day 4) follicular deviation, expression of PTGFR in bovine granulosa cells was more abundant in the dominant follicle after deviation than in subordinates (P < 0.

Intrafollicular lipopolysaccharide injection delays ovulation in cows.

The aim of this study was to evaluate effects of intra-follicular (i.f.) treatment with lipopolysaccharide (LPS) on follicular and luteal development in cows.

Effect of sperm kinematics and size of follicle at ovulation on pregnancy rate after timed AI of beef cows.

The objectives of this study were to evaluate whether the diameter of the preovulatory follicle and the post-thaw sperm kinematics are factors that affect successful establishment of a pregnancy after timed AI (TAI) of postpartum beef cows. Nelore cows (n = 346) were subjected to an estradiol-progesterone based TAI protocol. At TAI, cows were categorized according to the diameter of the preovulatory follicle (POF) in the Early Ovulation (EO group, n = 184), and Late Ovulation (LO group, n = 162) groups.

Uterine inflammation and fertility of beef cows subjected to timed AI at different days postpartum.

The aim of this study was to evaluate the uterine health and fertility of postpartum beef cows subjected to timed AI (TAI) protocols at different days from calving. Lactating Nelore cows (Bos indicus; n = 244) were used in this study. The TAI protocols were initiated between 20 and 60 days postpartum (DPP).

Different protocols using PGFα as ovulation inducer in Nelore cows subjected to estradiol-progesterone timed AI based protocols.

The objective of this study was to evaluate the effect of a PGFα-analogue (PGF) on ovulation and pregnancy rates after timed artificial insemination (TAI) in cattle. In Experiment 1 cows received an intravaginal progesterone-releasing device (CIDR) plus 2 mg im of estradiol benzoate (EB) on Day 0. The CIDR devices were removed on Day 8, and all cows received 150 μg im of d-cloprostenol (PGFα-analogue), 300 IU of eCG and 1 mg of estradiol cypionate (ECP) im.

The acute effect of intravenous lipopolysaccharide injection on serum and intrafollicular HDL components and gene expression in granulosa cells of the bovine dominant follicle.

The aim of this study was to evaluate the effect of an acute systemic inflammatory response induced by lipopolysaccharide (LPS) in the serum and follicular fluid (FF) high-density lipoprotein (HDL) components, hormone concentrations and granulosa cell gene expression. For this purpose, twenty non-lactating Jersey dairy cows were submitted to a progesterone (P4) - estradiol (E2) based synchronization protocol. Cows received a single i.

Predictive value of prepartum serum metabolites for incidence of clinical and subclinical mastitis in grazing primiparous Holstein cows.

The aim of this study was to measure changes in biochemical markers in the peripartum period of primiparous Holstein cows diagnosed with subclinical and clinical mastitis. In this study, 37 dairy cows were monitored daily during milking until 60 days postpartum and were categorized according to the occurrence of clinical mastitis (group mastitis (GM), n = 9) or subclinical mastitis (group subclinical mastitis (GSUB), n = 10) or absence of symptoms (control group (CG), n = 18). Blood samples were collected weekly from -30 to 60 days from calving.