Towards understanding the type and function of indigenous goats: input for genetic improvement and conservation programme

Figures & data

Figure 1. Map of the study area.

Figure 2. Morphological trait measurements (1, head length (HL); 2, head width (HW); 3, ear length (EL); 4, horn length (HOL); 5, neck girth (NG); 6, chest width (CW); 7, chest depth (CD); 8, wither height (WH); 9, cannon bone circumference (CBC); 10, chest girth (CG); 11, body length (BL); 12, paunch girth (PG); 13, rump height (RH); 14, rump length (RL); 15, rump width (RW)).

Table 1. Equation for computation of structural indices for Central Highland goats and their biological interpretation.

No.	Indices	Equation	Biological interpretation	References
1	Body index (BOI)	(BL/CG)*100	>0.90, the animal is longiline; from 0.86 to 0.88 is medigline; and <0.85, it is brevigline	Khargharia et al. (2015)
2	Dactyl thorax index (DTI)	(CBC/CG)*100	The DTI may not be more than 10.5 in light animals, up to 10.8 in intermediary; up to 11.0 in light meat animals and up to 11.5 in heavy meat type.	Chacon et al. (2011); Khargharia et al. (2015)
3	Body ratio (BR)	WH/RH	If the withers are lower than the rump, the animal is low in front and vice versa.	Chiemela et al. (2016)
4	Thoracic development (THD)	CD/WH	This indicates thoracic development of animals, with values above 1.2 indicating animals with good THD.	Dauda (2018)
5	Conformation index (CI)	CG^2/WH	Should be close to 2.1 the bigger the index, the closer the animal is to the traction type; the smaller this index, the weaker the animal will be	Dauda (2018)
6	Compact index (CPI)	BW/WH/100	Compact index indicates how compact the animal is. Meat-type animals have values above 3.15. Value close to 2.75 indicates dual purpose and close to 2.60 indicates that the animals are more suitable for milk purpose.	Chacon et al. (2011); Khargharia et al. (2015)
7	Relative depth of thorax index (RDI)	CD* 100/WH	RDI value >50 indicates the animal’s tendency to a meat phenotype.	Hernández et al. (2002), Parés (2009), Silva-Jarquin et al. (2019)
8	Transversal pelvic index (TPI)	RW*100/WH	TPI >33 indicators of meat breeds.	Hernández et al. (2002), Silva-Jarquin et al. (2019)
9	Longitudinal pelvic index (LPI)	RL*100/WH	LPI <37 is an indicator of meat breeds.	Hernández et al. (2002), Silva-Jarquin et al. (2019)
10	Height slope (HS)	WH-RH	–	Salako (2006)
11	Length index (LI)	BL/WH	–	Salako (2006)
12	Width index (WDI)	RW/CW	–	Salako (2006)
13	Proportionality (PPI)	(WH/BL)*100	–	Chiemela et al. (2016)
14	Pelvic index (PLI)	(RW/RL)*100	–	Chiemela et al. (2016)
15	Depth index (DI)	CD/WH	–	Khargharia et al. (2015)
16	Balance (BAL)	(RL*RW)/(CD*CW)	–	Khargharia et al. (2015)
17	Area (AI)	BL*WH	–	Khargharia et al. (2015)

BL = body length, WH = wither height, CG = chest girth, CW = chest width, CD = chest depth, RH = rump height, RL = rump length, RW = rump width, CBC = cannon bone circumference.

Table 2. Structural indices (LSM ± SE) of indigenous goats.

Indices	Overall	CV %	Highland	Lowland	Midland	P-value
BOI	89.3 ± 0.26	6.12	91.1 ± 0.38^a	86.3 ± 0.44^b	91.3 ± 0.36^a	<0.0001
DTI	12.3 ± 0.04	8.40	12.1 ± 0.08^b	12.6 ± 0.08^a	12.1 ± 0.06^b	<0.0001
BR	1.02 ± 0.001	3.83	1.03 ± 0.003	1.02 ± 0.002	1.03 ± 0.003	0.5865
THD	1.05 ± 0.005	5.23	1.02 ± 0.004^c	1.07 ± 0.004^a	1.04 ± 0.003^b	<0.0001
CI	71.9 ± 0.47	13.6	67.7 ± 0.80^c	75.1 ± 0.86^a	71.1 ± 0.65^b	<0.0001
CPI	0.0033 ± 0.0	22.7	0.0030 ± 0.00^c	0.0034 ± 0.00^a	0.0033 ± 0.00^b	<0.0001
HS	1.65 ± 0.10	14.8	1.69 ± 0.21	1.52 ± 0.17	1.75 ± 0.18	0.6341
LI	0.93 ± 0.002	5.69	0.93 ± 0.004^b	0.91 ± 0.003^c	0.95 ± 0.003^a	<0.0001
PPI	107.5 ± 0.29	5.95	107.7 ± 0.55^b	109.3 ± 0.50^a	105.6 ± 0.43^c	<0.0001
PLI	68.3 ± 0.26	7.97	68.0 ± 0.49^b	66.0 ± 0.45^c	70.9 ± 0.41^a	<0.0001
WDI	0.96 ± 0.005	10.2	0.99 ± 0.01^a	0.91 ± 0.001^b	0.99 ± 0.007^a	<0.0001
DI	0.52 ± 0.001	5.77	0.50 ± 0.002^b	0.54 ± 0.002^a	0.50 ± 0.002^b	<0.0001
BAL	0.53 ± 0.003	11.8	0.55 ± 0.007^a	0.50 ± 0.004^b	0.54 ± 0.004^a	<0.0001
AI	4014.3 ± 32.4	17.7	3894.5 ± 59.3^c	4001.8 ± 56.0^b	4096.2 ± 50.6^a	<0.0001
TPI	19.4 ± 0.07	7.78	18.7 ± 0.17^b	19.5 ± 0.13^a	19.6 ± 0.11^a	<0.0001
LPI	28.4 ± 0.08	5.67	27.5 ± 0.12^b	29.6 ± 0.14^a	27.6 ± 0.09^b	<0.0001
RDI	51.7 ± 0.15	5.77	50.1 ± 0.26^b	53.80.22^a	50.3 ± 0.21^b	<0.0001

BOI = body index, DTI = dactyl thorax index, BR = body ratio, THD = thoracic development, CI = conformation index, CPI = compact index, HS = height slope, LI = length index, WDI = width index, PPI = proportionality index, PLI = pelvic index, DI = depth index, BAL = balance, AI = area index, TPI = transverse pelvic, LPI = longitudinal pelvic indices, RDI = Relative depth of thorax index.

Ns, P > 0.05, * = P < 0.05, ** = P < 0.01, *** = P < 0.001.

Means with different superscripts in each subclass within a column differ significantly (P < 0.05) from each other.

Table 3. Pearson correlation estimates for structural indices.

	BOI	DTI	BR	THD	CI	CPI	HS	LI	PPI	PLI	WDS	DI	BAL	AI	TPI	LPI	RDI
BOI
DTI	−0.11**
BR	0.08*	−0.07ns
THD	−0.54***	−0.26***	−0.24***
CI	−0.41***	−0.47***	−0.01ns	0.82***
CPI	−0.06ns	−0.50***	0.03ns	0.48***	0.82***
HS	0.10*	−0.10*	0.99***	−0.24***	0.02ns	0.07ns
LI	0.62***	−0.37***	−0.13**	0.32***	0.30***	0.38***	−0.11**
PPI	−0.62***	0.37***	0.12**	−0.31***	−0.29***	−0.37***	0.11*	−0.99***
PLI	0.09*	−0.43***	0.15**	0.09*	0.30***	0.38***	0.17**	0.21***	−0.21***
WDS	0.23***	−0.36***	0.13**	−0.02ns	0.15**	0.24***	0.15**	0.24***	−0.25***	0.61***
DI	−0.31***	−0.14**	−0.13**	0.67***	0.62***	0.44***	−0.12**	0.26***	−0.24***	−0.17**	−0.15**
BAL	0.19***	−0.17***	0.02ns	−0.06ns	0.02ns	0.08*	0.03ns	0.16**	−0.17***	0.42***	0.88***	−0.36***
AI	0.21***	−0.56***	0.90***	0.18***	0.67***	0.83***	0.29***	0.41***	−0.41***	0.43***	0.36***	0.23***	0.18**
TPI	−0.14*	−0.32**	−0.08ns	0.52***	0.59***	0.53***	−0.06ns	0.32**	−0.33**	0.75***	0.48***	0.28**	0.44***	0.41***
LPI	−0.34**	0.19**	−0.33**	0.58***	0.37***	0.17**	−0.34***	0.15*	−0.15*	−0.38***	−0.20**	0.57***	0.02ns	−0.06ns	0.31**
RDI	−0.32**	−0.14**	−0.13**	0.67***	0.62***	0.42***	−0.13*	0.25**	−0.24**	−0.11**	−0.15**	1.00***	−0.36**	0.23**	0.25**	0.57***

BOI = body index, DTI = dactyl thorax index, BR = body ratio, THD = thoracic development, CI = conformation index, CPI = compact index, HS = height slope, L = , length index, WD = , width index, PPI = proportionality index, PLI = pelvic index, DI = depth index, BAL = balance, AI = area index, TPI = transverse pelvic LPI = longitudinal pelvic indices, RDI = Relative depth of thorax index.

Ns = P > 0.05, P < 0.05, ** = P < 0.01, *** = P < 0.001.

Table 4. Eigenvectors and eigenvalues of the selected principal components for structural indices of Central Highland goats.

Indices	PC1	PC2	PC3	PC4	PC5
BOI	−0.036	0.312	−0.376	0.352	0.071
DTI	−0.241	−0.188	−0.052	−0.073	0.403
BR	−0.041	0.217	0.453	0.298	0.359
THD	0.322	−0.241	0.033	−0.121	0.050
CI	0.380	−0.086	0.198	−0.034	−0.099
CPI	0.353	0.051	0.136	0.070	−0.199
HS	−0.027	0.228	0.458	0.299	0.337
LI	0.259	0.132	−0.395	0.275	0.116
PPI	−0.256	−0.137	0.396	−0.271	−0.122
PLI	0.186	0.319	0.113	−0.242	−0.200
WDI	0.146	0.356	−0.020	−0.296	0.220
DI	0.279	−0.301	0.061	0.160	0.122
BAL	0.076	0.315	−0.109	−0.412	0.361
AI	0.296	0.205	0.144	0.185	−0.176
TPI	0.314	0.099	0.030	−0.329	0.117
LPI	0.170	−0.322	−0.122	−0.117	0.465
RDI	0.279	−0.301	0.061	0.160	0.122
Eigenvalue	5.511	3.884	2.290	1.943	1.082
Proportion	0.324	0.229	0.135	0.114	0.064
Cumulative	0.324	0.553	0.688	0.803	0.867

BOI = body index, DTI = dactyl thorax index, BR = body ratio, THD = thoracic development, CI = conformation index, CPI = compact index, HS = height slope, LI = length index, WDI = width index, PPI = proportionality index, PLI = pelvic index, DI = depth index, BAL = balance, AI = area index, TPI = transverse pelvic, LPI = longitudinal pelvic indices, RDI = relative depth of thorax index.

Figure 3. Loading plot of structural indices of Central Highland goats.

Table 5. Phenotypic correlation between live weight and morphological traits for female (below diagonal) and male (above diagonal) goats.

	BW	BL	WH	CG	CW	CD	RH	RL	RW	PG	HL	HW	MC	EL	NG	HOL	SC
BW		0.88***	0.91***	0.89***	0.56***	0.86***	0.90***	0.76***	0.84***	0.25**	0.77***	0.49***	0.59***	0.54***	0.67***	0.87**	0.64***
BL	0.83***		0.86***	0.82***	0.45***	0.81***	0.83***	0.72***	0.77***	0.28**	0.76***	0.46***	0.54***	0.47***	0.58***	0.81***	0.62***
WH	0.85***	0.82***		0.87***	0.52***	0.89***	0.91***	0.72***	0.80***	0.21**	0.80***	0.45***	0.55***	0.55***	0.61***	0.85***	67***
CG	0.91***	0.77***	0.84***		0.61***	0.90***	0.86***	0.82***	0.81***	0.35**	0.70***	0.61***	0.69***	0.52***	0.77***	0.85***	0.73***
CW	0.68***	0.50***	0.59***	0.72***		0.54***	0.53***	0.64***	0.69***	0.35**	0.28**	0.57***	0.65***	0.45***	0.69***	0.59***	0.48***
CD	0.85***	0.75***	0.80***	0.90***	0.69***		0.85***	0.77***	0.74***	0.18ns	0.73***	0.48***	0.64***	0.56***	0.67***	0.81***	0.66***
RH	0.83***	0.76***	0.89***	0.81***	0.61***	0.77***		0.76***	0.81***	0.29***	0.79***	0.48***	0.55***	0.49***	0.62***	0.84***	0.67***
RL	0.82***	0.68***	0.76***	0.86***	0.71***	0.86***	0.77***		0.777***	0.47***	0.53***	0.69***	0.77***	0.46***	0.81***	0.77***	0.61***
RW	0.83***	0.75***	0.81***	0.84***	0.68***	0.76***	0.76***	0.77***		0.44***	0.60***	0.64***	0.63***	0.43***	0.75***	0.80***	0.61***
PG	0.87***	0.69***	0.76***	0.89***	0.69***	0.77***	0.77***	0.83***	0.77***		0.14ns	0.64***	0.39***	0.08ns	0.52***	0.35**	0.27**
HL	0.67***	0.78***	0.71***	0.64***	0.33**	0.58***	0.68***	0.50***	0.62***	0.52***		0.32**	0.36***	0.42***	0.36**	0.76***	0.62***
HW	60.0***	0.42**	0.58***	0.69***	0.63***	0.62***	0.57***	0.73***	0.67***	0.72***	0.32***		0.68***	0.29**	0.79***	0.55***	0.48***
MC	71.0***	0.49***	0.62***	0.74***	0.69***	0.72***	0.60***	0.78***	0.69***	0.74***	0.30**	0.77***		0.44***	0.85***	0.63***	0.59***
EL	0.44***	0.43**	0.45***	0.42***	0.35**	0.41***	0.44***	0.42***	0.42***	0.35**	0.39***	0.34**	0.40***		0.38***	0.43***	0.40***
NG	0.66***	0.42**	0.55***	0.73***	0.73***	0.72***	0.56***	0.79***	0.65***	0.74***	0.21**	0.83***	0.83***	0.34**		0.68***	0.60***
HOL	0.80***	0.72***	0.75***	0.79***	0.65***	0.77***	0.72***	0.75***	0.74***	0.73***	0.62***	0.86***	0.65***	0.40***	0.63***		0.67***

BW = body weight, BL = body length, WH = wither height, CG = chest girth, CW = chest width, CD = chest depth, RH = rump height, RL = rump length, RW = rump width, PG = punch girth, HL = head length, HW = head width, EL = ear length, NG = neck girth, SC = scrotum circumference and HOL = horn length.

** = P < 0.01, *** = P < 0.001.

Table 6. Multiple regression analysis of live weight on different morphological traits of female Central Highland goats.

No.	Prediction equation	R^2	R^2 change	P-value
1	−34.5 + 0.83*CG	0.825	–	<.0001
2	−39.5 + 0.59*CG + 0.34*BL	0.871	0.046	<.0001
3	−39.9 + 0.35*CG + 0.35*BL + 0.23*PG	0.887	0.016	<.0001
4	−42.8 + 0.32*CG + 0.31*BL + 0.20*PG + 0.14*RH	0.891	0.004	<.0001
5	−43.5 + 0.27*CG + 0.33*BL + 0.17*PG + 0.14*RH + 0.23*MC	0.894	0.003	<.0001
6	−42.5 + 0.30*CG + 0.30*BL + 0.19*PG + 0.15*RH + 0.37*MC + 0.15*HW	0.898	0.004	<.0001
7	−47.7 + 0.27*CG + 0.31*BL + 0.19*PG + 0.16*RH + 0.27*MC – 0.55*HW + 0.16*NG	0.900	0.002	<.0001
8	−42.7 + 0.25*CG + 0.27*BL + 0.20*PG + 0.13*RH + 0.29*MC – 0.61*HW + 0.21*NG + 0.30*HL	0.910	0.010	<.0001

CG = chest girth, BL = body length, PG = paunch girth, RH = rump height, MC = muzzle circumference, HW = hip width, NG = neck girth, HL = head length.

Table 7. Multiple regression analysis of live weight on morphological traits of male Central Highland goats.

No.	Prediction equation	R^2	R^2 change	P-value
1	−41.3 + 0.95*WH	0.830	–	<.0001
2	−42.0 + 0.56*WH + 0.41*CG	0.874	0.044	<.0001
3	−41.1 + 0.40*WH + 0.32*CG + 0.24*BL	0.890	0.016	<.0001
4	−43.0 + 0.25*WH + 0.25*CG + 0.22*BL + 0.28*RH	0.899	0.009	<.0001
5	−41.3 + 0.23*WH + 0.21*CG + 0.19*BL + 0.23*RH + 0.55*RW	0.901	0.002	<.0001
6	−40.3 + 0.16*WH + 0.23*CG + 0.20*BL + 0.25*RH + 0.73*RW – 0.03*PG	0.910	0.009	<.0001
7	−33.6 + 0.15*WH + 0.22*CG + 0.21*BL + 0.30*RH + 0.72*RW – 0.04*PG + 0.20*HOL	0.911	0.001	<.0001

WH = wither height, CG = chest girth, BL = body length, RH = rump height, RW = rump width, PG.

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Data availability

None of the data were deposited in an official repository. However, the data that support the study findings are available to reviewers, available from authors upon request.