Reproduction continues to be a critical component to maintain a dairy farm economically viable. For every farm and for every cow, there is an optimum time for pregnancy, which is mostly influenced by level of production, persistency of lactation, and parity. In general, as production decreases, lactation number increases, and persistency of lactation decreases, cows should be bred sooner postpa...

This study compares in two experiments the responses of lactating dairy cows to four different progesterone-based protocols for fixed-time artificial insemination (FTAI) in terms of their effects on follicular/luteal dynamics and fertility. The protocols consisted of a progesterone intravaginal device fitted for five days, along with the administration of different combinations of gonadotropin ...

Grazed pasture, which is the cheapest source of nutrients for dairy cows, should form the basis of profitable and low-input animal production systems. Management of high-producing dairy cows at pasture is thus a major challenge in most countries. The objective of the present paper is to review the factors that can affect nutrient supply for grazing dairy cows in order to point out areas with sc...

Abstract The reproductive efficiency of the cows was monitored after two resynchronization protocols: Ovsynch (OVS) and Double (DOS). research initially included 70 HF who entered first synchronization protocol – Presynch. Cows that did not conceive were divided into groups introduced to protocols. In group (n=35), DOS began with application GnRH on day 22 Presynch TAI (Timed Artificial Insemin...

Experiment 1 evaluated pregnancy rates (PRs) when estradiol cypionate (ECP) replaced the second GnRH injection of a timed artificial insemination (TAI) protocol for lactating dairy cows. Cows were pre-synchronized with two injections of PGF2α (Lutalyse r , Pharmacia Corp., 25 mg; i.m.) given to multiparous cows (n=170) at 40 ± 3 and 54 ± 3 d postpartum (dpp) and to primiparous cows (n=201) at 6...

The objective of the study was to determine the effect of replacing triticale (high rumen degradable starch) with maize grain (low rumen degradable starch) during the transition period and the first 120 days of lactation on metabolic and hormonal profile indices, milk production and fertility performance in cows. Forty-eight Holstein-Friesian dairy cows were divided into 4 groups: TT (2.5 kg tr...

The aim of this study was to evaluate the effect of replacing progesterone injections by progesterone vaginal inserts on productive and reproductive parameters of lactating cows with reproductive problems after prolonged periods of heat stress. Fifteen Holstein cows were randomly assigned to one of three treatments: 1) treated with two progesterone vaginal inserts (P4-INS); 2) treated with prog...

Early identification of nonpregnant dairy cows post breeding can improve reproductive efficiency and pregnancy rate by decreasing the interval between AI services and increasing AI service rate. Thus, new technologies to identify nonpregnant dairy cows early after artificial insemination (AI) may play a key role in systematic management strategies to improve reproductive efficiency and profitab...

The aim of work is to explore influence first fruitful insemination, service period and dry dairy productivity Simmental cows. research aimed at studying the milk production cows with different levels reproductive qualities. result research, a relation was established between age duration period, performance. It has been that insemination 18-24 months most beneficial effect on subsequent produc...

Objectives were to compare circulating progesterone (P4) profile and pregnancies per AI (P/AI) of two commercial intravaginal P4 devices (PRID-Delta(®) vs CIDR(®)). In Experiment 1, ovariectomized dairy cows (PRID-Delta, n=6 vs CIDR, n=6) were sampled throughout 7 days to measure circulating P4. In Experiment 2 (PRID-Delta, n=399 vs CIDR, n=375), cows were assigned to treatments, as follows: D0...