Table 3.

Strategies for cost-effective implementation of sexed semen in the cattle industry.

Aim	Breed	Evidence	Estrus detection	Strategy	Reference
To achieve higher pregnancy rates based on the animal’s reproductive performance	Holstein (heifers and cows)	Experiment	N/A	To prioritize the insemination of heifers instead of cows	(97)
To increase the overall net return and genetic level through a phased implementation of sexed semen	Not specified	Model-baseda	N/A	To have a herd with high management for reproductive performance and to inseminate 75% of the genetically superior heifers with sexed semen and 70% of the genetically inferior multiparous cows with beef semen. Changes in the genetic level have to be considered	(99)
To achieve the highest total economic return through dairy crossbreeding and genomic test	Swedish Holstein	Model-basedb	N/A	Use 90% sexed semen in heifers and 45% sexed semen in first-parity cows combined with genomic test and crossbreeding (+58€, 33% crossbreds in the herd)*	(109)
	Swedish Red		N/A	Use 90% sexed semen in heifers combined with genomic test and crossbreeding (+94€, 46% crossbreds in the herd)*
To increase the pregnancy rate based on the time of AI	Holstein (dairy heifers)	Experiment	An accelerometer system and a neck collar comprising an electronic identification tag	To inseminate 20.1-24 h after estrus detection, coupled with a temperature-humidity index at the time of artificial insemination below 65	(110)
	Jersey (virgin heifers)		Tail-head chalk (checked twice a day for removal)	To inseminate 16.1–24 h after estrus detection (instead of 12–16 h)	(111)
	Jersey (lactating cows)		Tail-head chalk (checked daily for removal of tail paint or standing estrus) and secondary signs evaluation (increased nervousness and activity, walking the fence line, and swelling and reddening of the vulva)	To inseminate 23–41 h after estrus detection (instead of ≤3 h, 4–12 h, 13–22 h, and ≥42 h)	(112)
	Jersey (dairy heifers)		N/A	To inseminate 60 h after the removal of the intravaginal progesterone device (instead of 54 h)	(113)
	Nelore cows (suckled, multiparous)		N/A	To inseminate 60 h after the removal of the intravaginal progesterone device (instead of 48 h or 36 h) OR To inseminate 0–12 h before ovulation (compared to 12–24 h and >24 h)

^*Compared with a pure-breeding scenario, without sexed semen and genomic test; AI, Artificial insemination; N/A, Not applicable.

^aCombination of two stochastic simulation models: SimHerd and ADAM.

^bCombination of two stochastic simulation models: SimHerd Crossbred (operational returns) and ADAM (genetic returns).