Triplet lambs and their dams – a review of current knowledge and management systems

Figures & data

Figure 1. Meta-analysis (Overall Effect) and meta-regression coefficients of lamb birth weight across studies. Individual study means and SE (black dots and bold horizontal lines) represent the difference in lamb birthweight between singletons vs. triplets and twins vs. triplets. Overall random-effects meta-analysis and meta-regression coefficients (mean, ± 95 CI) for studies comparing lamb birth weights in studies without any treatments (No treatment) applied, those that imposed a treatment designed to either increase (+ treatments) and decrease (− treatments) lamb birth weight. The difference in magnitude between studies comparing singletons or twins vs. triplets (Single vs. Twin Comparison).

Table 1. The weight of triplet lambs within a given study as the proportion of its singleton and twin counterparts (note the analysis includes 61 individual studies, but some studies has more than one comparison group).

	Triplet birthweight as a proportion
Reference	Singletons	Twin
Al-Gubory 1998	0.65	0.80
Al-Gubory 1998	0.66	0.77
Al-Gubory et al. 1999	0.64	0.89
Al-Gubory et al. 1999	0.60	0.76
Anilkumar et al. 2011	0.63	0.86
Avdi and Chemineau 1998	0.81	0.90
Avdi and Chemineau 1998	0.71	0.79
Avdi and Driancourt 1997		0.90
Boujenane 2012	0.72	0.85
Brand et al. 2014	0.71	0.84
Chniter et al. 2011	0.72	0.86
Cloete et al. 2002	0.65	0.80
Cloete et al. 2002	0.67	0.82
Cloete et al. 1993	0.66	0.83
Corner et al. 2008		0.84
Davies et al. 1971	0.66	0.77
de Miranda and McManus 2000	0.41	0.52
Demiroren et al. 1995	0.71	0.84
Doloksaribu et al. 2000	0.53	0.70
Dwyer 2003	0.76	0.84
Dwyer 2003	0.59	0.78
Dwyer 2003	0.65	0.83
Dwyer and Morgan 2006	0.66	0.84
Dwyer et al. 2005	0.61	0.74
Emsen and Yaprak 2006	0.51	0.67
Everett-Hincks and Cullen 2009	0.62	0.80
Gallo and Davies 1988	0.81
Gatenby et al. 1997	0.66	0.85
George 1976	0.68	0.82
George 1976	0.60	0.74
Gootwine and Rozov 2006	0.68	0.83
Gootwine et al. 1995	0.61	0.75
Hadjipieris and Holmes 1966	0.67	0.96
Hadjipieris and Holmes 1966		0.91
Halliday 1971	0.67	0.79
Halliday 1974	0.63	0.76
Hinch et al. 1983	0.59	0.81
Hinch et al. 1983	0.60	0.76
Holst et al. 2002	0.67	0.85
Holst et al. 2002	0.69	0.86
Holst et al. 2002	0.66	0.81
Holst et al. 2002	0.63	0.77
Holst et al. 2002	0.71	0.85
Holst et al. 2002	0.71	0.85
Hutton et al. 2011		0.78
Jafaroghli et al. 2010	0.67	0.80
Janos et al. 2018	0.73	0.95
Juengel et al. 2018		0.84
Kenyon et al. 2014	0.74	0.82
Kenyon et al. 2010a		0.85
Kenyon et al. 2010b		0.82
Kenyon et al. 2006		0.84
Kenyon et al. 2006		0.83
Kerslake et al. 2010a		0.80
Kerslake et al. 2010b		0.81
Kerslake et al. 2010c		0.82
Kerslake et al. 2009		0.79
Khalaf et al. 1979	0.54	0.72
Khalaf et al. 1979	0.60	0.80
Khalaf et al. 1979	0.69	0.79
Kumar et al. 2008	0.70	0.86
Knight et al. 1985	0.64	0.79
Knight et al. 1985	0.68	0.87
Knight et al. 1985	0.70	0.82
Knight et al. 1985	0.72	0.89
Leibovich et al. 2000	0.58	0.76
Leibovich et al. 2000	0.78	0.93
Manalu and Sumaryadi 1998	0.74	0.88
Mellado et al. 2016	0.56	0.66
Mishra et al. 2006	0.68	0.85
Mishra et al. 2008	0.71	0.85
Morris and Kenyon 2004		0.80
Muhle et al. 2010	0.56	0.78
Ritar et al. 1990	0.77	0.87
Roche et al. 2012	0.74	0.91
Rosov and Gootwine, 2013	0.67	0.82
Ruttle 1971	0.68	0.77
Scales et al. 1986	0.63	0.80
Scaramuzzi et al. 1993	0.71	0.89
Shelton et al. 1991	0.57	0.68
Shrestha et al. 1992	0.71	0.85
Sormunen-Cristian and Jauhiainen 2001		0.73
Sormunen-Cristian and Jauhiainen 2001		0.75
Sormunen-Cristian and Jauhiainen 2001		0.74
Stafford et al. 2007	0.59	0.67
Mean	0.66	0.81
Minimum	0.41	0.52
Maximum	0.94	0.96

Table 2. The effect of birth rank on lamb survival to weaning. Note the table consists of data from 29 studies, but some studies had more than one comparison.

		Percentage (%) of surviving lambs
Study Author	Year	Singletons	Twins	Triplets
Anilkumar et al.	2011	92.7	85.9	67.7
Bichard and Cooper	1966	87.9	85	66
Boujenane	2012	99	94	88
Chniter et al.	2011	96.1	90.1	84.8
Cloete et al.	1993	92.5	92	72.2
Cloete et al.	1993	87.5	89.7	63
Corner et al.	2008		84.7	70.4
Demiroren et al.	1995	80	80	73
Doloksaribu et al.	2000		81.4	45.3
Gatenby et al.	1997	94.5	90.2	72.2
Gootwine et al.	1995	93	90	77
Hanford et al.	2006	90.1	94.8	88.8
Hinch et al.	1983	88.5	75.6	50.3
Hinch et al.	1983	92.9	82.4	65.1
Hinch et al.	1996	85.4	78.5	55.8
Hutton et al.	2011		90	69
Jafaroghli et al.	2010	89	89.8	83.67
Juengel et al.	2018		84.9	74.1
Kenyon et al.	2006		80.4	60.3
Kenyon et al.	2006		80.7	53.9
Kenyon et al.	2010a		90.1	78.4
Kenyon et al.	2010a		84	65
Kenyon et al.	2011			69.5
Kenyon et al.	2011			56
Kenyon et al.	2011			61.7
Kenyon et al.	2011			64.5
Kenyon et al.	2011			60.3
Kenyon et al.	2011			56.7
Kenyon et al.	2011			62.7
Kenyon et al.	2011			57.7
Kenyon et al.	2012			66.8
Kenyon et al.	2012			72.9
Kenyon et al.	2012			71.1
Kenyon et al.	2012			75.1
Kenyon et al.	2012			65.1
Kenyon et al.	2013			67.45
Kenyon et al.	2013			61.9
Kenyon et al.	2013			76.1
Kenyon et al.	2013			72
Kenyon et al.	2013			65.4
Kenyon et al.	2014	94.6	83.7	76.2
Kerslake et al.	2009		94	73
Kerslake et al.	2010a		85.2	62
Khalaf et al.	1979	100	82	58.4
Khalaf et al.	1979	92.9	86.2	73
Khalaf et al.	1979	100	100	78.8
Knight et al.	1985	84	78	63
Knight et al.	1985	88	87	67
Knight et al.	1985	81	77	59
Knight et al.	1985	88	83	56
Mellado et al.	2016	71	74	64.7
Morris and Kenyon	2004		86	68
Scales et al.	1986	85.9	85.3	67
Shrestha et al.	1992	84	84	72
Mean		89.5	85.5	67.5
Lower quartile		85.9	81.8	61.9
Upper quartile		93.0	90.0	73.0

Table 3. Comparison^a of causes of death (%) of newborn lambs as identified by autopsy.

	Pre-natal death				Dystocia^b		Starvation exposure			Dystocia/starvation exposure			Other^f
	S^c	Tw^d	Tpl^e	S	Tw	Tpl	S	Tw	Tpl	S	Tw	Tpl	S	Tw	Tpl
Cloete et al. 1993				25	25	30	50	19	30		13		25	43	40
Cloete et al. 1993				100	27	50		22	22		6	8		45	20
Hinch et al. 1986	17	10	31	33	40	38	0	10	13	17	17	14	33	23	9
Hinch et al. 1986	17	21	28	57	36	36	3	11	11	13	7	8	10	26	15
Hinch et al. 1986	0	3	0	68	36	33	13	12	17	7	30	33	13	18	17
Holmøy et al. 2017				48	30	29	5	5	7				48	65	64
Holst et al. 2002				33	14	24	10	23	22	49	49	44	8	14	10
Kerslake et al. 2005				61	49	50	20	29	27	7	9	9	11	13	14
Scales et al. 1986	3	12	7	75	39	7	13	33	50	1	3	29	6	13	7
Range	0–17	3–21	0–31	25–100	14–49	7–50	0–50	5–33	7–50	1–49	3–49	8–44	6–48	13–65	7–64

^aAs identified by autopsy.

^bDystocia includes prolonged birth, rupture and central nervous system damage.

^cS – Single.

^dTw - Twin.

^eTpl – Triplet.

^fOther – either another cause of death or unknown.

Note: Individual % values have been rounded to the nearest whole number.

Table 4. The effect of birth rank and rearing rank on lamb weight (kg) at weaning.

Reference^1	Twin /Twin	Triplet/Triplet	Triplet/Twin	Triplet/Singleton
Morris and Kenyon 2004	27.4 ± 0.4^c	22.7 ± 0.5^a	25.3 ± 0.5^b
Kenyon et al. 2010a	23.1 ± 0.5	22.5 ± 0.6	23.7 ± 0.8
Kenyon et al. 2010b	24.4 ± 0.5^b	22.2 ± 0.7^a	22.6 ± 0.7^a
Kerslake et al. 2010a	16.0 ± 0.3^b	14.5 ± 0.7^a	15.1 ± 0.6^ab
Hutton et al. 2011	20.8 ± 0.4^b	17.6 ± 0.5^a	17.9 ± 0.7^a	15.3 ± 1.3^a
Kenyon et al. 2011a		18.8 ± 0.3^a	19.6 ± 0.3^a	22.0 ± 0.6^b
Kenyon et al. 2011b		24.2 ± 0.7^a	26.1 ± 0.6^ab	28.0 ± 1.0^b
Kenyon et al. 2012		25.5 ± 0.6^a	27.2 ± 0.7^b	28.7 ± 1.1^ab
Kenyon et al. 2013		21.0 ± 0.6^a	23.8 ± 0.6^b	26.8 ± 1.0^c

¹Data adapted from the various studies.

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