Absolute Growth (G/day) and Relative Growth (%) of Cattle Groups

0.66kg. After 24 months of raising, the weight of the cow groups reached: 352.50

± 1.38kg, 370.71 ± 1.19kg, 402.45 ± 1.34kg and 423.55 ± 1.14kg. Mass gain

The average absolute weight gain during 24 months of rearing was respectively: 448.65g, 472.03g, 511.94g and 539.03g/day. Thus, the highest absolute weight gain was achieved in HF cows and the lowest in F1 cows , in order of decreasing HF blood ratio in crossbred animals.

The coefficient of variation of weight over the corresponding months of rearing in the groups of F 1 , F 2 , F 3 and HF cows at birth was: 8.10%, 7.52%, 7.59% and 6.61%, with a tendency to decrease after 24 months of age and reached respectively: 4.17%, 3.49%, 3.58% and 4.33%.

4 5 0

4 0 0

3 5 0

3 0 0

2 5 0

2 0 0

1 5 0

F 1

F 2

F 3

1 0 0

5 0

1 2

Last month

1 8

2 4

The weight of HF cows at different ages is always larger than that of crossbred cows. Statistical comparison shows that the weight of cows at different ages is significantly different (P < 0.05) and when the HF blood ratio increases, the weight of cows at different ages also increases. The change in weight of cows at different ages can be seen more clearly in Figure 3.1.

Weight (kg)

Figure 3.1. Cow weight by month of age

The results of absolute and relative growth of the monitored cow groups are presented in table 3.2; charts 3.1 and figure 3.3.

Table 3.2. Absolute growth (g/day) and relative growth (%) of cattle groups

statistics

Months old stage

Group

SS – 6 7 – 12 13 –18 19 – 24

Th.s	absolute	relative	absolute	relative	absolute	relative	absolute	relative
	558.58a	125.92	456.79a	47.80	413.09a	29.98	366.19a	20.64
F 1 SE	5.03	0.62	8.84	0.84	9.21	0.69	5.47	0.31
(n = 114) Cv%	9.61	5.23	20.67	15.74	23.81	24.60	15.95	15.94
	592.36 b	126.53	479.79 b	47.73	415.77a	28.60	399.45 b	21.62
F 2 SE	4.91	0.56	8.36	0.76	7.15	0.41	6.77	0.40
(n = 118) Cv%	8.99	4.78	18.93	17.31	18.36	15.24	18.42	19.52
	643.31 c	126.14	518.69 c	47.54	471.49b	29.71	414.26 BC	20.46
F 3 SE	4.15	0.53	5.47	0.45	7.37	0.44	5.86	0.31
(n = 116) Cv%	6.88	4.54	11.35	10.27	16.85	16.02	15.24	16.37
	681.15 d	126.55	554.04 d	47.94	490.49b	29.33	430.40 c	20.14
HF SE	3.71	0.35	5.09	0.41	4.68	0.30	5.02	0.23
(n = 257) Cv%	8.73	4.44	14.72	13.60	15.29	16.54	18.69	18.32

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TT TT cow

TT TT

(Mean numbers with different letters in the same column are statistically different, P < 0.05).

The data in Table 3.2 show that the average daily growth of the F 1 , F 2 , F 3 and HF cow groups reached their highest from birth to 6 months of age, respectively: 558.58 ± 5.03g, 592.36 ± 4.91g, 643.31 ± 4.15g and 681.15

±3.71g, at age 7 - 12 months old: 456.79 ± 8.84g, 479.79 ± 8.36g, 518.69

± 5.47g and 554.04 ± 5.09g and the age group of 19 to 24 months reached respectively: 366.19 ± 5.47g, 399.45 ± 6.77g, 414.26 ± 5.86g and 430.40 ± 5.02g. Thus,

The growth of the cow groups is highest in the newborn - 6 month old stage, then gradually decreases, the lowest is in the 19 - 24 month old stage. The growth of F1 cows is lowest and the highest is in HF cows (in increasing order as the HF blood ratio increases). Absolute growth is low from the 7 - 12 month old stage onwards, proving that the growth of cows follows the main law of absolute growth. Statistical comparison shows that the absolute growth in the newborn - 6 month, 7 - 12 month stages of different cow groups is statistically significant (P < 0.05). At the stage

In the period of 19-24 months, the absolute growth of F 3 cows compared to HF, and of F 2 cows compared to F 3 cows were not statistically different (P > 0.05). The difference in this index between F 1 cows compared to F 2 , F 3 and HF cows was significant (P < 0.05).

Similar to absolute growth, relative growth of cow groups reached its highest in the neonatal – 6-month period, respectively: 125.92

± 0.62%; 126.53 ± 0.56%; 126.14 ± 0.53% and 126.55 ± 0.35% then decreased

gradually, reaching 20.64 ± 0.31% at 19 - 24 months of age; 21.62 ± 0.40%;

20.46 ± 0.31% and 20.14 ± 0.23% respectively.

F 1

F 2

F 3

7 0 0

6 0 0

5 0 0

4 0 0

3 0 0

2 0 0

1 0 0

SS _ 6

7 _ 1 2

1 3 _ 1 8

1 9 _ 2 4

Early adolescence

Absolute growth (g/day)

Figure 3.1. Absolute growth of cattle groups

F 1

F 2

F 3

1 4 0

1 2 0

1 0 0

8 0

6 0

4 0

2 0

SS _ 6

7 _ 1 2

1 3 _ 1 8

1 9 _ 2 4

Early adolescence

Relative density (%)

Figure 3.2. Relative growth of cattle groups

3.1.1. 2 Dimensions of some dimensions and body composition indexes of cattle groups

The dimensions and some body composition indexes of the monitored cow groups are presented in tables 3.3 and 3.4. The data obtained in tables 3.3 and 3.4 show that the measurements of fin height, chest circumference and diagonal body length of F1 cows at 6 months of age were the lowest (94.95 ± 0.36 cm, 120.39

± 0.47cm and 105.48 ± 0.43cm) and the highest was HF cow (103.79 ± 0.30cm,

126.75 ± 0.33cm and 112.87 ± 0.25cm). In general, these measurements at 6 months of age of the cow groups were in the range: 94.95 ± 0.36cm – 103.79 ± 0.30cm, 120.39 ± 0.47cm – 126.75 ± 0.33cm and 105.48 ± 0.43cm – 112.87 ±

0.25cm respectively.

At the ages of 12, 18, 24 months, the values of the measurements also had similar rules and at 24 months, these measurements of the groups of cows F 1 , F 2 , F 3 and HF were in the corresponding ranges: 125.38 ± 0.55cm - 134.65 ± 0.27cm, 173.97 ± 0.56cm - 180.52 ± 0.37cm and 144.24 ± 0.46cm - 152.15 ± 0.30cm. The results

This result shows that the dimensions of the cow group are quite large.

The coefficient of variation of the measurements of the cow groups was relatively low (2.33% - 4.90%), showing that the growth rate of the cow measurements was quite uniform.

The body length, body roundness and weight indexes at 6 months of age of the F 1 , F 2 , F 3 and HF groups ranged from 111.23 ± 0.82 – 108.76 ± 0.29; 114.68 ± 0.71 – 112.31 ± 0.28 and 126.95 ± 0.62 – 122.03 ± 0.29. After 24

The coefficient of variation in the rearing month was 115.20 ± 0.61 - 112.99 ± 0.36; 120.72 ± 0.48 - 118.78 ± 0.36 and 139.01 ± 0.70 - 134.10 ± 0.35, respectively.

The error of these indices also has relatively low values (3.35% - 7.84%).

From the above results, it can be seen that across ages, the dimensions of HF cows are the largest and the lowest are F1 cows . However, the body composition indices tend to be the highest in F1 cows and the lowest in HF cows. Body composition indices

	CV	VN	DTC	CV	VN	DTC	CV	VN	DTC	CV	VN	DTC
	94.95a	120.39a	105.48a	103.25a	144.18a	115.94a	115.85a	160.89a	130.83a	125.38a	173.97a	144.24a
F 1 SE	0.36	0.47	0.43	0.35	0.45	0.25	0.49	0.49	0.37	0.55	0.56	0.46
Cv%	4.04	4.11	4.30	3.56	3.34	2.38	4.48	3.25	3.02	4.71	3.41	3.39
	96.88 b	120.86a	106.61b	105.88b	146.59 b	117.16b	118.36b	164.43b	133.29b	126.47a	175.72 b	145.82 b
F 2 SE	0.41	0.43	0.40	0.50	0.44	0.24	0.45	0.54	0.48	0.57	0.48	0.43
Cv%	4.59	3.86	4.12	5.07	3.27	2.47	4.11	3.56	3.88	4.90	2.98	3.19
	101.80 c	124.32b	110.07 c	110.16 c	149.55 c	120.96 c	122.74 c	166.51 c	135.79 c	129.38b	176.84 b	148.75 c
F 3 SE	0.40	0.37	0.42	0.33	0.41	0.31	0.47	0.43	0.40	0.51	0.54	0.40
Cv%	4.23	3.16	4.12	3.25	2.98	2.69	4.08	2.79	3.16	4.28	3.31	2.88
	103.79 d	126.75 c	112.87 d	113.06 d	151.41 d	123.44 d	126.56 d	169.77 d	138.84 d	134.65 c	180.52 c	152.15 d
(n=257) SE	0.30	0.33	0.25	0.27	0.38	0.18	0.30	0.33	0.31	0.27	0.37	0.30
Cv%	4.65	4.17	3.57	3.85	4.04	2.33	3.80	3.15	3.53	3.20	3.31	3.14

Cow group

Statistics

Table 3.3. Size (cm) of some measurements by month of age of cow groups

Months old

6 12 18 24

(n=114)

(n=118)

(n=116)

(Mean numbers with different letters in the same column are statistically different, P < 0.05). Note: TSTK: Statistical parameters, CV: Fin height, VN: Chest circumference, DTC: Diagonal body length

Group Th.so6			12			18			24
	CSDT	CSTM	Customer Service	CSDT	CSTM	Customer Service	CSDT	CSTM	Customer Service	CSDT	CSTM	Customer Service
	111.23a	114.68a	126.95a	112.43a	124.41 ab	139.75a	113.15a	123.06	139.08a	115.20a	120.72a	139.01a
(n=114) SE	0.82	0.71	0.62	0.44	0.45	0.61	0.56	0.45	0.60	0.61	0.48	0.70
Cv%	7.84	6.58	5.23	4.20	3.87	4.68	5.43	3.94	4.60	5.65	4.24	5.34
	110.27a	113.43a	124.96 b	110.77 b	125.18a	138.55a	112.81a	123.44	139.12a	115.54a	120.63a	139.23a
F 2 SE	0.51	0.47	0.59	0.40	0.46	0.53	0.51	0.48	0.62	0.58	0.49	0.68
Cv%	5.04	4.51	5.10	3.91	3.97	4.16	4.81	4.19	4.82	5.47	4.37	5.27
	108.30b	113.01 ab	122.31 c	109.92b	123.73 BC	135.86 b	110.81b	122.26	135.85 b	115.18a	118.96 b	136.89 b
(n=116) SE	0.47	0.43	0.56	0.42	0.47	0.48	0.49	0.44	0.51	0.54	0.49	0.57
Cv%	4.69	4.06	4.92	4.09	4.12	3.72	4.79	3.89	4.04	5.09	4.37	4.49
	108.76 b	112.31b	122.03 c	109.26b	122.65 c	134.21 c	109.56 c	122.59	134.21 c	112.99 b	118.78b	134.10 c
(n=257) SE	0.29	0.28	0.29	0.23	0.28	0.36	0.33	0.33	0.39	0.36	0.36	0.35
Cv%	4.21	3.96	3.83	3.35	3.36	4.26	4.78	4.34	4.71	5.12	4.87	4.20

beef

Table 3.4. Some physical structure indexes of cattle groups

Months old

F 1

(n=118)

F 3

(The average numbers with different letters in the same column are statistically different, P < 0.05). Note: TSTK: Statistical parameters, CSDT: Body length index, CSTM: Body roundness index, CSKL: Mass index

This figure of the cow groups approximates the corresponding indices of specialized dairy cows. This shows that when crossing HF cows and Sind crossbred cows, the crossbreds have a body constitution index that is inclined towards milk production.

3.1.2 Growth ability of experimental cow groups

3.1.2.1 Cumulative, absolute and relative growth

The results of growth performance of the experimental cattle group are presented in tables 3.5; 3.6 and illustrated in figures 3.3; graphs

3.2 and figure 3.4.

Table 3.5. Weight of cows (kg) from birth to 24 months of age

statistics	Newborn	6 months	12 months	18 months	24 months
F	33.46	143.49b	227.51 b	305.25 b	374.59 b
1 SE	0.17	0.68	0.88	0.91	1.16
(n = 20) Cv%	2.33	2.11	1.74	1.33	1.38
F	33.42	148.42 c	246.78 c	328.22 c	401.18 c
2 SE	0.20	0.41	1.44	1.82	3.03
(n = 20) Cv%	2.66	1.25	2.61	2.49	3.37
F	33.64	157.40 d	258.18 d	342.63 d	420.89 d
3 SE	0.11	0.91	1.39	1.14	2.37
(n = 20) Cv%	1.52	2.60	2.41	1.49	2.52
HF	33.58	164.67a	274.60a	362.30a	448.96a
(n = 20) SE	0.12	0.52	0.93	0.78	2.25
Cv%	1.57	1.40	1.51	0.96	2.24

Cow group Th. number

Months old

(Mean numbers with different letters in the same column are statistically different, P < 0.05)

The results obtained in Table 3.5 show that the birth weight of the cow groups F 1 , F 2 , F 3 and HF are respectively: 33.46 ± 0.17kg, 33.42 ± 0.20kg, 33.64

± 0.11kg and 33.58 ± 0.12kg. After 24 months of age, the weight of F1 cows is low.

First, the mass increased gradually with increasing HF blood percentage and was highest in HF cows.

The weight at 24 months of age of the F 1 , F 2 , F 3 and HF groups was respectively: 374.59 ± 1.16 kg, 401.18 ± 3.03 kg, 420.89 ± 2.37 kg and 448.96 ± 2.25 kg.

During the 24 months of raising, the coefficient of variation in weight of the F1, F2, F3 and HF experimental groups had lower values than the monitoring group. This shows that the experimental group of cows grew and developed quite evenly, this uniformity was due to the result of the selection process right from the beginning of the experiment.

Thus, across ages, the weight of HF cows was higher than that of crossbreds. Similar to the monitored cow group, the weight of the cow groups tended to increase as the percentage of HF blood in crossbreds increased.

At birth, the weight of the cow groups was quite uniform. Therefore, the difference in weight between the cow groups was not statistically significant (P > 0.05). However, at other ages, the weight of the cow groups was statistically significant (P < 0.05).

Compared with the monitoring group, the experimental group had higher weights across ages. The low coefficient of variation in weight over months of rearing (monitoring: 3.49% - 8.10%, experimental rearing: 0.96% - 3.37%) demonstrated that the difference in weight at the beginning of rearing did not adversely affect the difference in weight of individuals during the rearing process.

Nguyen Kim Ninh (1994)[72] reported that the F 1 herd (HF x crossbred Sind) raised in mass in Ba Vi at 6 months old reached 98.4 ± 1.37 kg, 12 months old was 151.4 ± 1.53 kg, in the experimental herd the corresponding weight was 115.3 ± 3.78 kg and 183.0 ± 5.01 kg. The F 3 herd (HF x crossbred Sind) had corresponding weights according to these ages: 119.1 - 128.9 kg and 191.17 - 200.6 kg.

According to Nguyen Van Thuong and CS (2008)[189], HF cows raised in households in Moc Chau at birth, 6 months and 12 months reached the following weights: 34.42 ± 3.43kg - 35.02 ± 3.41kg, 132.20 ± 11.47kg - 133.30 ± 11.53kg, respectively.

According to Tran Trong Them (2006)[92], the average weight of F2 cows ( HF x crossbred Sind) in Ha Tay, Hanoi and Ho Chi Minh City at birth, 6 months, 12 months, 18 months and 24 months is respectively: 32.46 ± 0.37kg, 128.83 ± 1.54kg,

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