Session VII: Products and marketing

Beef production of three yak breeds in Tibet

J. Qiumei, B. Chong, D. Yongla, T. Degyi, D. Chyegi, Zh. Yongqing and L. Sang

Tibetan Livestock Research Institute, Lhasa 850000, Tibetan Autonomous Region, P.R. China

Summary

Three animals from both sexes from the Pali, Sibu and Jiali yak (two males as an exception) were slaughtered to evaluate their beef production characteristics by various measurements. The results show that the dressing percentages, net beef percentages, ratios of net beef to carcass weight, eye muscle areas, and ratios of bone to net beef weight were 49.47%, 40.74%, 81.84%, 61.09 cm² and 1:4.56 for the Pali yak, 50.59%, 43.02%, 85.09%, 64.55 cm² and 1:4.21 for the Jiali yak and 46.67%, 37.4%, 79.62%, 45.41 cm² and 1:3.96 for the Sibu yak in Tibet, respectively. Further nutrients tests indicate that yak beef produced in Tibet is rich in protein, amino acids and minerals but less of fat. We, therefore, proposed yak beef production have a very promising market.

Keywords: Amino acids, beef, bone, minerals, dressing percentage, Tibet, yak

Introduction

Yak beef has higher protein and lower fat contents than normal beef. As a natural and ecologically clean food, the yak beef produced on the Tibetan Plateau has an increasing demand in recent years. Most importantly, yak beef is the main source of animal protein and energy to all the Tibetan nomads. This paper presents the measured characteristics of yak beef produced by three Tibetan yak breeds and explore the potential of yak beef production by considering the optimum slaughter time, reducing the input and enhancing the economy of Tibetan yak production system.

Materials and methods

Seventeen adult, healthy and middle body-conditioned animals grazing under natural pasture were purchased and transferred from Pali, Jiali and Sibu yak producing areas to Lhasa in 1997 and 1998. After several days acclimatisation and being fasted for 24 hours, the animals were slaughtered for various measurements to evaluate the beef productivity and related characteristics on site. Fresh samples were immediately collected, frozen and sent for further laboratory analyses in the Southwest Nationality College in Chengdu, Sichuan.

Results and discussion

Live weight

From both the body confirmation and live weight, it is found that the Pali yak is the largest, followed by Jiali yak and Sibu is the smallest (Table 1).

Table 1. Measurements of carcass of three yak breeds in Tibet.

Breeds	Sex	No.	Liveweight  (kg)	Carcass weight (kg)	Carcass length (cm)	Eye muscle area (cm2)	Net beef (kg)	Dressing percentage  (%)	Net beef (%)	Net beef/ carcass (%)	Bone/ beef
Jiali	♂	2	314.45	157.89	134.00	82.25	140.89	50.38	44.97	89.24	1:4.16
	♀	3	203.45	103.21	119.33	46.85	83.54	50.79	41.06	80.94	1:4.25
Pali	♂	3	332.74	164.58	123.33	74.45	137.15	50.84	42.40	83.17	1:4.96
	♀	3	221.59	106.58	111.33	47.72	85.75	48.10	39.08	80.50	1:4.16
Sibu	♂	3	254.65	114.13	128.00	45.97	88.67	44.76	34.82	77.69	1:3.48
	♀	3	205.94	101.29	120.67	44.84	82.62	49.18	39.98	81.55	1:4.43

Carcass measurements

Table 1 shows that Jiali male yak have the largest eye muscle area (82.3 cm²), followed by Pali (74.5 cm²) and Sibu yak (45.9 cm²), however, the value for female Jiali and Pali yak are almost the same and Sibu also is the smallest one. Most of the carcass characteristics of Tibetan yak are much lower than those of Jiulong yak, one of the top yak breeds in Sichuan (Zhong 1997), but the eye muscle area is just a little smaller than the Jiulong yak and larger than Tianzhu White yak in Gansu (50.3 cm²).

The Jiali yak further shows higher dressing percentage, net beef weight, net beef/carcass weight and eye muscle area than Pali and Sibu yak which represent that the beef productivity of Jiali yak is the best followed by the Pali and Sibu yak.

It was reported that that average carcass weights and dressing percentages for male and female Sibu yak were 206.87 kg and 53.15%, and 106.00 kg and 46.33%, respectively, and average carcass weights, dressing percentages, net beef rates, eye muscle areas and ratios of bone to beef were 208.5 kg, 55%, 46.89%, 50.63cm² and 1:5.63 for male Jiali yak and 128.34 kg, 49.54%, 42.76%, 43.28cm², and 1:6.70 for female Jiali yak, respectively (Dou 1990). Thus it is concluded that beef productivity of the Sibu yak has been tending to decrease. The dressing percentage and net beef rate of the Jiulong yak were 47–56% and 37.84–45.57%, respectively. The dressing percentage, net beef rate and ratio of bone to beef of the castrated adult Tianzhu White yak were 54.6, 41.4% and 1:4.07, and the dressing percentage and net beef rate of castrated adult Qinghai-Plateau and Maiwa yak were 53 and 42.5%, and 55.2 and 42.8%, respectively (Zhang 1989). The beef productivity of the Tibetan yak is still not very low considering the data from other breeds and is capable of being improved through feeding, management and selection of the breeding animals.

Nutrients and minerals in the Tibetan yak beef

Table 2 shows that the yak beef has higher crude protein but less fat, especially those found in the eye muscle. However, the crude protein in the rib muscle is higher than in the eye muscle, in particular for the females.

Table 2. Nutrients of Tibetan yak beef (%).

Breeds	Sex	Muscles	Water	Crude protein	Crude fat	Ash
Pali	♂	Eye muscle	74.24	22.56	2.06	1.033
		Rib muscle	54.93	17.82	25.29	0.843
	♀	Eye muscle	75.22	22.18	2.41	1.07
		Rib muscle	43.61	15.04	40.5	0.675
Jiali	♂	Eye muscle	75.25	21.38	2.33	1.05
		Rib muscle	68.35	21.23	9.42	1.00
	♀	Eye muscle	74.37	22.34	2.22	1.07
		Rib muscle	69.01	19.11	11.01	0.87
Sibu	♂	Muscles	73.39	22.60	2.98	1.03
		Eye muscle	68.18	20.45	10.43	0.94
	♀	Rib muscle	73.42	22.86	2.72	1.00
		Eye muscle	58.60	17.86	22.67	0.87

Trace elements in the Tibetan yak beef is relatively higher than in the Jiulong yak, especially for Fe and Mg which are possibly resulted from the higher trace elements in the soil, forage and water but remains for future survey (Table 3).

Table 3. Minerals in muscles of Tibetan yak.

Breeds	Sex	Muscles	Zn (mg/kg)	Fe (mg/kg)	Mn (mg/kg)	Cu (mg/kg)	Mg (mg/kg)	Ca (mg/kg)	Co (mg/kg)
Pali	♂	Eye muscle	83.470	81.598	30.892	30.892	304.813	324.235	0.071
		Rib muscle	39.130	83.176	19.525	13.863	258.057	297.560	0.128
	♀	Eye muscle	92.138	91.293	29.621	25.581	314.034	308.986	0.236
		Rib muscle	64.275	111.984	34.036	31.663	215.513	290.014	0.203
Sibu	♂	Eye muscle	94.827	188.693	46.599	25.842	187.147	–	0.1603
		Rib muscle	85.956	179.303	51.391	21.801	201.467	–	0.158
	♀	Eye muscle	107.680	204.429	26.292	21.520	190.112	–	0.589
		Rib muscle	80.370	202.899	27.074	22.214	220.349	–	0.209

Amino acids in Tibetan yak beef

Beef of Tibetan yak is affluent in variety of amino acids but at a lower total content compared with the Jiulong yak (84.90 and 82.38% in rib and eye muscle, respectively) and Tianzhu White yak (90.18 and 91.16% in rib and eye muscle, respectively) probably due to its poorer feeding and management (Table 4). Among three breeds of Tibetan yak, the Pali yak has a higher total value of amino acids followed by the Sibu and Jiali yak.

Table 4. Amino acids in muscles of Tibetan yak (%).

	Sibu				Pali				Jiali
	♂		♀		♂		♀		♂		♀
	Rib muscle	Eye muscle	Rib muscle	Eye muscle	Rib muscle	Eye muscle	Rib muscle	Eye muscle	Rib muscle	Eye muscle	Rib muscle	Eye muscle
Aspartic acid	2.25	2.27	1.91	2.41	2.64	2.15	2.67	2.10	2.37	2.06	1.97	2.11
Threonine	1.00	1.08	0.85	1.09	1.34	1.12	1.35	1.10	1.21	1.06	1.02	1.11
Serine	0.81	0.84	0.69	0.83	1.14	0.89	1.18	0.87	0.99	0.83	0.83	0.88
Glutamic acid	3.81	3.85	3.13	4.14	6.19	5.09	6.23	4.95	5.58	4.88	4.65	5.03
Glycine	1.58	0.89	0.93	0.88	1.85	0.93	1.91	0.90	1.28	0.90	1.10	0.91
Alanine	1.68	1.33	1.25	1.49	2.15	1.58	2.19	1.53	1.44	1.50	1.54	1.56
Cystine	0.29	0.20	0.23	0.26	0.18	0.14	0.23	0.12	0.16	0.14	0.15	0.17
Valine	1.09	1.03	0.93	1.15	1.44	1.17	1.50	1.14	1.29	1.11	1.10	1.15
Methionine	0.58	0.66	0.52	0.71	0.67	0.56	0.64	0.54	0.57	0.56	0.46	0.56
Isoleucine	1.02	1.03	0.86	1.15	1.40	1.20	1.39	1.16	1.32	1.18	1.10	1.22
Leucine	2.01	2.04	1.74	2.19	2.61	2.16	2.28	2.10	2.39	2.10	1.98	1.12
Tyrosine	0.74	0.81	0.65	0.89	0.92	0.81	0.96	0.79	0.87	0.79	0.69	0.80
Phenylalanine	1.04	0.96	0.86	1.01	1.24	0.99	1.30	0.98	1.11	0.94	0.93	0.98
Lysine	1.99	2.10	1.76	2.23	2.20	1.90	2.30	1.88	2.08	1.80	1.61	1.52
Histidine	0.70	0.89	0.69	0.92	1.01	0.89	0.95	0.87	0.89	0.80	0.69	0.83
Arginine	1.41	1.29	1.09	1.43	2.01	1.53	2.03	1.51	1.76	1.48	1.44	1.52
Proline	1.06	0.64	0.72	0.66	1.42	0.83	1.44	0.73	1.02	0.75	0.85	0.76
Total (%)	23.06	21.91	18.81	23.44	30.41	23.94	30.35	23.27	26.33	22.88	22.11	22.23

Special remarks

Pali, Sibu and Jiali yak are three preferred yak breeds in Tibet, which have been supporting the Tibetan nomads' life providing the necessary productive and subsistence materials. Yak beef, rich in protein, amino acids and trace minerals and less of fat, is the main product of yak production, which plays a key role in providing animal protein and energy to the Tibetans living on the cold highlands. It is also natural and unpolluted green meat favoured by the increasing markets. Tibet has a large number of yak and related natural resources to support a sustainable yak industry. However, owing to the constraints from both the marginal eco-geographical location and infrastructures, the potential of yak production has not been well developed. The authors recommend that an effective use of the natural forage resource should be considered for the sustainable yak production, the key backbone industry to the local Tibetan socio-economy.

Acknowledgements

The authors acknowledge all the technical supports from the Jiali Bureau of Animal Husbandry, Jiali Breeding Animal Station, Pali Township, Yadong Veterinary Service Station, Kangbu Township in Yadong County, Mezhugongka County Government, Mezhugongka Farm, Southwestern Nationality College, Sichuan Sanitation and Prevention Station, Sichuan Livestock Research Institute, Tibet First People's Hospital.

References

Guanghui Z. 1997. Research of selection and breeding of the Jiulong yak. Sichuan Nationality Press, Chengdu, P.R. China. [in Chinese].

Rongchang Z. 1989. China yak. Gansu Scientific and Technology Press, Lanzhou, P.R. China, 386 pp. [in Chinese].

Yaozun D. 1990. Tibetan yak. Collection of papers on the Tibetan animal husbandry and veterinary. 1980–1990. Lhasa, P.R. China. [in Chinese].