Treatments to Optimize the Use of Artificial Insemination and Reproductive Efficiency in Beef Cattle under Tropical Environments

Table 4

Reproductive endpoints in prepubertal Bos indicus heifers that received, between d-12 and 0, no treatment (CIDR0), a new intravaginal insert containing 1.9 g of progesterone (CIDR1), or a similar intravaginal insert that had previously been used three times (CIDR4). The breeding season started on d 1 and consisted of AI after estrus detection between d 1 and 45 and exposure to bulls between d 46 and 90. Adapted from Claro Júnior et al. [15].

Dependent variable	Treatment
	CIDR0	CIDR1	CIDR4
Progesterone on d 0, ng/mL^a	0.37±0.16	2.31±0.11	1.20±0.11
Follicle diameter on d 0, mm^a	9.45±0.24	9.72±0.17	11.42±0.16
Uterine score on d 0^a	1.49±0.06	1.88±0.04	2.24±0.04
Interval to estrus, d^a	4.4±0.28	3.48±0.13	3.24±0.14
Estrus detection in 7 d, % (n)^a	19.5 (22/113)	42.6 (101/237)	39.3 (94/239)
Conception rate in 7 d, % (n)^a	27.3 (6/22)	33.7 (34/101)	46.8 (44/94)
Pregnancy rate in 7 d, % (n)^a	5.3 (6/113)	14.3 (34/237)	18.4 (44/239)
Estrus detection in 45 d, % (n)^a	52.2 (59/113)	72.1 (171/237)	75.3 (180/239)
Pregnancy rate in 45 d, % (n)^a	27.4 (31/113)	39.2 (93/237)	47.7 (114/239)
Pregnancy rate in 90 d, % (n)^a	72.6 (82/113)	83.5 (198/237)	83.7 (200/239)

aTreatment (𝑃<.05).