Comparison of Cumulative Growth of Sindhi Crossbred Calves in Cho Don District with F1 Crossbred Calves (Red Sindhi Bull X Local Cow)

growth curves are different at different age stages. The later the growth curves are, the further apart they become.

In the same group of calves (Sind crossbred or local calves), the cumulative growth performance curve of male calves always lies above the growth performance curve of female calves.

* Comparing the cumulative growth of Sindhi crossbred calves in Cho Don district with F1 crossbred calves (Red Sindhi bull x local cow) from other localities (kg)

To evaluate the growth ability of Lai Sind calves in Cho Don district, we compared them with Lai Sind calves from some other localities. The results are shown in Table 3.10:

Table 3.10: Comparison of cumulative growth of Sindhi crossbred calves in Cho Don district with F1 crossbred calves (Red Sindhi bull x local cow)

of other localities (kg)

Distinction

Months old	Sind crossbred calf Don Market	F 1 calf Lap Thach*	F 1 calf Thai Nguyen**
Male	Newborn	19.30  0.56	17.74  0.46	17.86 ± 0.29
	6	85.60 ± 1.96	82.97 ± 2.59	85.80 ± 2.20
	12	134.96  3.63	142.44  3.22	186.37  4.01
Female	Newborn	18.10  0.59	16.98 ± 0.32	18.25  0.24
	6	76.60 ± 0.8	79.84 ± 1.95	82.18  2.45
	12	121.60 ± 2.77	136.01  2.65	146.92 ± 2.58

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* Data by Luu Xuan Thuy, 2000 [29], ** Data by Pham Gia Huynh, 1997 [11]

Comments: Looking at table: 3.10, we can see that in the newborn stage, the weight of Lai Sind Cho Don calves is higher than that of calves from Thai Nguyen and Lap Thach localities, but later on, especially at 12 months of age,

The calves from the other two localities gained weight much faster than the Lai Sind calves from Cho Don. This can be explained by the fact that:

- The Sind blood ratio of F1 calves in Lap Thach and Thai Nguyen is higher than that of Cho Don calves due to the purity of the father, so the influence of hybrid advantage is higher, leading to higher weight gain of crossbred calves in later stages.

- Due to different microclimates and different care and nurturing conditions of people in Cho Don and the other two localities.

3.2.3. Absolute growth and relative growth of Sindhi crossbred and local calves

To evaluate the growth ability of Lai Sind calves based on the results of monitoring the accumulated weight at different age stages, we determined the absolute growth ability and relative growth ability of Lai Sind calves according to the characteristics. At the same time, we compared the obtained results with the corresponding indicators of local calves. The results are shown in Table 3.11.

Table 3.11: Absolute growth of Sindhi crossbred and local calves

(gr/head/day)

Months old

Male ( X )			The ( X )
Local	Lai Sind	Compare LS/DP (%)	Local	Lai Sind	Compare LS/DP (%)
SS-3	329.09	415.93	126.39	296.08	383.52	129.53
3 - 6	246.09	320.86	130.38	240.40	266.74	110.96
6 - 9	212.41	280.06	131.85	224.21	265.48	118.41
9-12	203.81	267.89	131.44	147.46	234.22	158.84
SS-12 Average	247.85	321.19	129.59	227.04	287.49	126.63

The figures in Table 3.11 show:

- The absolute growth of calves is highest from birth to 3 months of age: Lai Sind male calves reach 415.93 gr/head/day, local male calves reach 329.09 gr/head/day, Lai Sind female calves reach 383.52 gr/head/day, local female calves reach 296.08 gr/head/day. The reason is that at this stage, calves are provided with perfect nutrition from their mother's milk and this is completely consistent with the growth laws of cattle according to stages.

- Stage 3 to 6 months old: Lai Sind male calves reach 320.86 gr/head/day, local male calves reach 246.09 gr/head/day, Lai Sind female calves reach 266.74 gr/head/day, local female calves reach 240.4 gr/head/day. The reason is that at this stage, calves have started to eat but their digestive system is not yet complete while the source of nutrition from mother's milk is reduced, so growth is reduced.

- Stage 6 to 9 months old: Lai Sind male calves reach 280.06 gr/head/day, local male calves reach 212.41 gr/head/day, Lai Sind female calves reach 265.48 gr/head/day, local female calves reach 224.21 gr/head/day. The reason is that at this stage, the calves have started to get used to food but the source of nutrition from mother's milk is no longer there, so growth is reduced. At this stage, it is very necessary to supplement concentrated feed in the diet to meet the growth needs of the calves.

- During the entire period from birth to 12 months of age, absolute growth in Lai Sind male calves reached 321.19 gr/head/day and in Lai Sind female calves reached 287.49 gr/head/day. Meanwhile, in local male calves it reached 247.85 gr/head/day and in local female calves it reached 227.04 gr/head/day.

Thus, the absolute growth of crossbred Sind male calves is 33.7gr/head/day higher than crossbred Sind female calves, corresponding to 11.7%, and local male calves are 20.81gr/head/day higher than local female calves, corresponding to 9.16%.

- When comparing the two groups of calves, the absolute growth capacity of crossbred Sind calves is always greater than that of local calves: Crossbred Sind male calves have an absolute growth capacity greater than that of local male calves by 73.34 gr/head/day, corresponding to 29.59%, this index in crossbred Sind female calves and local female calves is 60.45 gr/head/day, corresponding to 26.63%.

450.00

400.00

350.00

300.00

250.00

200.00

150.00

100.00

50.00

0.00

415.93

383.52

329.09

296.08

320.86

321.19

266.74

246.09

280.06

265.48

224.21

287.49

267.89

234.22

203.81

247.85

240.40

227.04

212.41

147.46

§úc §P

LS LS PC

SS-3 3-6T

6-9T

Month of age

9-12T

Weight (g/head/day)

To see more clearly the difference in absolute growth of the 2 groups of calves and in 2 different sexes, we illustrate the results in chart 3.2.

Figure 3.2. Absolute growth of Sindhi crossbred and local calves

The absolute growth chart of the two groups of calves shows:

- The absolute growth of Sind crossbred calves is always higher than that of local calves of the same sex and age.

- Absolute growth increases rapidly in the neonatal stage - 3 months of age and then gradually decreases in the following age stages.

The results of comparison of relative growth ability of 2 groups of calves across age stages are presented in Table 3.12.

Table 3.12: Relative growth of Sindhi crossbred and local calves (%)

Months old

Male		Female
Local	Lai Sind	Local	Lai Sind
SS - 3	32.22	32.79	32.31	32.56
3 - 6	13.06	13.52	13.97	12.39
6 - 9	8.26	8.55	9.27	8.99
9 -12	6.38	6.54	4.96	6.33

The results presented in Table 3.12 show that:

The relative growth of the two groups of calves in the two sexes followed the general rule of decreasing with age.

- Sind crossbred male calves decreased from 32.79% in the newborn - 3 month old stage to 6.54% in the 9-12 month old stage and from 32.56% to 6.33% in Sind crossbred female calves.

35.00

30.00

25.00

20.00

15.00

§úc §P

LS LS PC

10.00

5.00

0.00

SS-3

3-6T

6-9T

9-12T

Month of age

R (%)

- Local male calves decreased from 32.22% in the newborn - 3 month old stage to 6.38% in the 9-12 month old stage and from 32.31% to 4.96% in local female calves.

Graph 3.4: Relative growth of Sindhi crossbred and local calves (%)

3.2.4. Dimensions of some main dimensions of local and Sind cross calves

To more comprehensively assess the stature of the Sindhi and local calves, we have followed a number of key measurements. The results are presented in Table 3.13.,

Table 3.13: Some measurements of local and Sind cross calves ( X )

Distinction

Months old	n (child)		VN (cm)		DTC (cm)		CV (cm)		VO (cm)
Months old	DP	LS	DP	LS	DP	LS	DP	LS	DP	LS
Male	3	6	7	82.50	88.67	71.50	77.22	71.33	75.00	9.08	9.33
	6	6	7	95.90	103.56	78.70	85.44	77.70	86.56	10.45	10.94
	9	6	7	103.17	114.13	87.17	91.13	86.17	92.13	11.58	12.06
	12	6	7	108.80	117.40	95.00	104.80	96.60	104.20	13.30	13.40
Female	3	6	7	80.43	87.00	67.43	74.38	67.29	73.30	8.71	9.13
	6	5	7	93.67	99.13	76.17	84.07	75.50	81.93	10.29	10.57
	9	5	7	101.71	109.57	85.43	89.57	85.86	89.86	11.50	11.79
	12	5	7	105.00	114.40	93.17	99.40	95.17	101.60	12.92	13.10

The figures in Table 3.13 show:

All dimensions increased with age in both groups of calves, but the rate of increase in dimensions was different at each stage. The table above shows that at all stages, the dimensions of male calves were always larger than those of female calves.

- For Sind crossbred calves:

+ At 3 months of age, male calves have the following dimensions: Chest circumference (VN): 88.67 cm; diagonal body length (DTC): 77.22 cm; fin height (CV): 75.00

cm; tube circumference (VO): 9.33 cm. Female calves with corresponding measurements are: VN: 87.00 cm; DTC: 74.38 cm; CV: 73.30 cm; VO: 9.13 cm. In general, at this stage, the size of the measurements between male and female calves is not very different.

+ At 12 months of age, male calves have the following measurements: VN: 117.40 cm; DTC: 104.80 cm; CV: 104.20 cm; VO: 13.40 cm. Female calves with

The corresponding measurements are: VN: 114.40; DTC: 99.40 cm; CV: 101.60 cm; VO: 13.10 cm. Thus, at this stage, there is a significant difference between male and female calves in dimensions such as: VN, DTC, CV.

- For local calf groups.

+ At 3 months of age, male calves have the following dimensions: Chest circumference (VN): 82.50 cm; diagonal body length (DTC): 71.50 cm; fin height (CV): 71.33 cm; tube circumference (VO): 9.08 cm. Female calves have the following corresponding measurements: VN: 80.43 cm; DTC: 67.43 cm; CV: 67.29 cm; VO: 8.71 cm. At this stage, the dimensions between male and female calves have differences in DTC and CV.

+ At 12 months of age, male calves have the following measurements: VN: 108.80 cm; DTC: 95.00 cm; CV: 96.60 cm; VO: 13.3 cm. Female calves have the following measurements: VN: 105.00; DTC: 93.17 cm; CV: 95.17 cm; VO: 12.92 cm. Thus, at this stage, there is an insignificant difference in the measurements between male and female calves.

From the experiment on the influence of 7/8 Sind blood bulls on the survival and growth rate of crossbred calves, we concluded that crossbreeding has a clear effect on increasing the growth of offspring compared to purebred local calves, due to the renewed genetic potential for growth .

3.3. RESEARCH RESULTS ON THE EFFECT OF SUPPLEMENTARY FEEDING ON FEEDING AFTER WEANING HYBRID CALFS FROM 6 TO 10 MONTHS OLD

Through research on the effects of supplementing concentrated feed in the diet of crossbred calves from 6 to 10 months old, we obtained the following results:

3.3.1. Survival rate of Sind cross calves over experimental months

To evaluate the survival rate of the Sind crossbred calf herd, we regularly monitored the households, the results are shown in Table 3.14.

Table 3.14: Survival rate of calves over experimental months

Experimental month

Experimental calf		Control calf
Number of children alive (child)	Survival rate (%)	Number of children alive (child)	Survival rate (%)
Start TN	10	100	10	100
1	10	100	10	100
2	10	100	10	100
3	10	100	10	100
4	10	100	10	100

The results in Table 3.14 show that: The survival rate of Sind cross calves reached 100% in the experimental months (1, 2, 3, 4 experimental months) in both experimental and control groups.

The reason may be that the calves after the milk-feeding stage have gradually become accustomed to the living conditions and the hybrid advantage has been promoted, making the vitality of the crossbred calves better. In addition, farmers have also improved their cattle raising techniques, especially with the guidance and help of students and interns in caring for and raising the experimental herds of cattle of the families, so the survival rate of the Sind crossbred calves is high.