Effects of herd fertility on the economics of sexed semen in a high-producing, pasture-based dairy production system

Abstract

This study used a stochastic simulation model to estimate the potential economic benefit of using sexed semen in heifers only and in heifers and lactating cows in a high-producing, pasture-based system under 3 fertility scenarios. Three breeding strategies were modeled:(1) only heifers inseminated with sexed semen and cows inseminated with conventional unsexed semen (SSH);(2) both heifers and cows inseminated with sexed semen (SSHC); and (3) a reference scenario in which all females were inseminated with conventional, unsexed semen (CONV). Each scenario was evaluated under 3 herd fertility states: high (HF), medium (MF), and low (LF), which, under the reference scenario, corresponded to herd replacement rates of 21, 25, and 31%, respectively. The model estimated the economic profit, including the net present value of the genetic gain from selection intensity. The economic return from adoption of sexed semen strategies declined, with reduced levels of baseline herd fertility turning negative in the LF state. The mean (±SD) sexed semen advantage (SSA) per cow for HF-

Economics of timed artificial insemination with unsorted or sexed semen in a high-producing, pasture-based dairy production system

“…For TSEX-H and TSEX-HC, the relative P/AI of SS compared with conventional AI was the most critical parameter to the range in annual ∆PROF. Similar to Walsh et al (2021) this parameter was associated with substantially greater financial variability when used in heifers and cows compared with heifers only (see Figure 3). The P/AI of SS relative to conventional AI had more effect on the annual ∆PROF per cow in TSEX-HC (€100.28) than in TSEX-H (€14.23) with more SS doses being used in the TSEX-HC scenario.…”

“…The difference in our results compared with Calsamiglia et al ( 2018) and Tenhagen et al (2004) may be attributable to the greater economic importance of fertility in seasonal pasture-based systems. Conversely, with the adoption of SS, Walsh et al (2021) and Seidel (2003) found dairy herds with already low reproductive performance using CONV are less likely to realize a financial advantage from sexed semen use as potentially reduced P/AI amplify existing fertility challenges. In less fertile herds adoption of TAI alone may return a positive annual ∆PROF by increasing the proportion of cows bred earlier in the breeding period.…”

“…The P/AI of SS relative to conventional AI had more effect on the annual ∆PROF per cow in TSEX-HC (€100.28) than in TSEX-H (€14.23) with more SS doses being used in the TSEX-HC scenario. Walsh et al (2021) reported that use of sexed semen in a fixed herd size in heifers and cows in a high herd fertility state with a modal SS pregnancy rate of 87% relative to conventional semen returned a substantial profit advantage (€49.14/cow per year) over a conventional unsorted semen reproductive policy. Similarly, we found that in a fixed herd size TSEX-HC with a modal SS relative P/AI of 84% to conventional semen returned a profit advantage relative to CONV.…”

“…We used a stochastic whole farm simulation model to evaluate the bio-physical and financial effects of TCONV and TSEX reproductive technologies. A brief explanation of the University College Dublin Lyons Dairy Simulation Model is provided here for context, and a more detailed description of the methodology is documented by Walsh et al (2021). The model operates on a monthly timestep to provide a comprehensive framework that integrates animal inventory, milk production, feed requirements and supply, genetic gain, land, and labor utilization of a high-producing pasturebased dairy production system (see Figure 1).…”

“…Genetic gain was modeled in a similar way to Walsh et al (2021). The financial contribution of genetic gain was simulated as the change in the herd economic merit based on Ireland's Economic Breeding Index for dairy cattle.…”