Field synchronization of Ethiopian Highland sheep for fixed time artificial insemination: improvement of conception rate with a double injection of prostaglandin at 11 days

Figures & data

Figure 1. Schematic representation of the experimental design. P₄+ECG group: ewes synchronized with the standard protocol using intravaginal polyurethane sponges and 1 injection of ECG. PGF_S group: ewes synchronized with 1 injection of dinoprost. PGF₇ and PGF₁₁ groups: ewes synchronized with two injections of dinoprost given 7 and 11 days apart respectively, starting 13 days before the timed artificial insemination (Day 0). AI: day of artificial insemination. LTA: Lambing to AI between 145 and 155 days.

Table 1. Differences in conception rate (CR) and litter size (LS) according to the different parameters.

		Conception rate		Litter size		Multiple bearings
Parameter		Ewes conceiving/Total (%±SD)	P value	Number of lambs per lambing sheep (±SD)	P value	Number of ewes having multiple LS/Ewes conceiving (%±SD)	P value
Location	Menz	125/260 (48.08 ± 3.1)	0.511	136/120 (1.13 ± 0.4)	0.037*	15/120 (12.50 ± 3.0)	0.096^t
	Debre Birhan	100/223 (44.84 ± 3.3)		122/97 (1.26 ± 0.5)		22/97 (22.68 ± 4.3)
BCS	≤2	22/69 (31.88 ± 5.6)	0.487	27/22 (1.23 ± 0.4)	0.466	5/22 (22.73 ± 8.9)	0.515
	[2, 3] [3, 4]	116/227 (51.10 ± 3.3) 87/187 (46.52 ± 3.6)		135/111 (1.22 ± 0.5) 96/84 (1.14 ± 0.4)		20/111 (18.02 ± 3.6) 12/84 (14.29 ± 3.8)
Protocol	P4+eCG	55/121 (45.45 ± 4.5)^a	0.004**	79/55 (1.44 ± 0.6)^a	<0.001**	20/55 (36.36 ± 6.5)^a	0.050*
	PGFS	46/135 (34.07 ± 4.1)^a		49/46 (1.07 ± 0.2)^b		3/46 (6.52 ± 3.6)^cb
	PGF7	40/89 (44.94 ± 5.3)^a		41/40 (1.03 ± 0.2)^b		1/40 (2.50 ± 2.5)^b
	PGF11	84/138 (60.87 ± 4.2)^b		89/76 (1.17 ± 0.4)^b		13/76 (17.11 ± 4.3)^dc
Parity	1	99/207 (47.83 ± 3.5)	0.621	110/92 (1.20 ± 0.5)	0.365	14/92 (15.22 ± 3.7)	0.819
	2	48/108 (44.44 ± 4.8)		59/47 (1.26 ± 0.4)		12/47 (25.53 ± 6.4)
	3	42/89 (47.19 ± 5.3)		49/42 (1.17 ± 0.4)		7/42 (16.67 ± 5.8)
	4	35/76 (46.05 ± 5.7)		38/35 (1.09 ± 0.3)		3/35 (8.57 ± 4.7)
Overall		225/483 (46.58 ± 2.3)		258/217 (1.19 ± 0.4)		37/217 (17.05 ± 2.6)

CR: Conception rate.

LS: Litter Size.

SD: Standard Deviation.

P: probability.

*: Significant (0.001 ≤ p ≤ 0.05).

**: Highly significant (p < 0.001).

^t: Tendency.

Values with different superscripts (a, b, c and d) in the same column are significantly different (P < 0.05).

Table 2 Effect of synchronization protocols on lambing rate in Menz sheep

Parameter		LR (%)	P value
Protocol	P4+eCG	79/121 (65.29)^a	<0.001**
	PGFS	49/135 (36.30)^b
	PGF7	41/89 (46.07)^b
	PGF11	89/138 (64.49)^a
Overall		258/483 (53.42)

LR: Lambing Rate.

P: probability.

**: Highly significant (p < 0.001).

Values with different superscripts (a and b) in the same column are significantly different (P < 0.05).