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

TT TT TT

TT TT TT

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

The results in Table 3.6 show that, similar to the group of cows monitored, the average daily growth of the F 1 , F 2 , F 3 and HF groups raised in the experiment reached the highest from birth to 6 months of age (respectively: 611.31 ± 3.80g/day, 638.89 ± 2.29g/day, 687.53 ± 5.21g/day and 728.28g ± 2.74/day) and then tended to decrease gradually. At the stage of 19 to 24 months of age, the absolute growth of the cow groups reached the lowest, respectively: 385.22 ± 8.14g/day, 405.36 ± 10.79g/day, 434.78 ± 12.36g/day and 481.42g/day. ± 11.70g/day but still reached a higher value than the group of cows monitored. In general, the absolute growth during 24 months of the F 1 , F 2 , F 3 and HF groups raised in the experiment reached respectively: 576.92g, 473.79g, 510.78g and 537.85g/day, higher than the group of cows monitored. Thus, the group of cows raised in the experiment grew and developed quite well.

Similarly, the relative growth of the experimental cattle groups was highest from birth to 6 months of age, then gradually decreased. From birth to 6 months of age, the relative growth of the F 1 , F 2 , F 3 and HF groups was: 124.36 ± 0.41%, 126.49 ± 0.36%, 129.53 ± 0.41% and 129.53 ± 0.41%, respectively.

132.24 ± 0.22%. The corresponding period from 19 to 24 months of age is: 20.40 ± 0.32%,

19.98 ± 0.71%, 20.48 ± 0.66% and 21.34 ± 0.47%.

Thus, across ages, growth indicators in the experimental cattle groups were all higher than those in the monitoring group, and HF cattle always had the highest weight, followed by F3 and the lowest was F1 . In the neonatal stage to 6 months of age, there was almost no significant difference in weight, from 7 months of age onwards, the difference became larger, especially between HF cattle and crossbreds. The coefficient of variation in growth of the cattle groups during the entire experimental period was lower than that of the monitoring group, demonstrating that the experimental cattle herd had higher uniformity. In our opinion, due to better care and nutrition and a more balanced diet, the experimental cattle group grew better.

8 0 0

7 0 0

6 0 0

5 0 0

4 0 0

3 0 0

F 1

F 2

F 3 HF

2 0 0

1 0 0

0

SS _ 6

7 _ 1 2

1 3 _ 1 8

1 9 _ 2 4

Early adolescence

Absolute growth (g/day)

Figure 3.2. Absolute growth of cattle groups

F 1

F 2

F 3

HF

1 4 0

1 2 0

1 0 0

8 0

6 0

4 0

2 0

0

SS _ 6

7 _ 1 2

1 3 _ 1 8

1 9 _ 2 4

Early adolescence

Relative growth (%)

Figure 3.4. Relative growth of cattle groups

3.1.2.2 Dimensions of some body measurements and body composition index

The dimensions of some dimensions and body composition indices of experimental cattle are presented in tables 3.7 and 3.8.

Cow group

Statistics

Table 3.7. Dimensions of some dimensions (cm) of cow groups by month of age

Months old

6 12 18 24

(n=20)

(n=20)

66

(n=20)

HF

(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

Cow group

Statistics

Table 3.8. Some physical structure indexes of cow groups by month of age

Months old

6 12 18 24

67

(n=20)

(n=20)

(n=20)

(n=20)

(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

The obtained data showed that similar to the group of monitored cows, in the experimental groups of cows, the measurements of F1 cows were the lowest, the highest was HF cows and also increased gradually according to the level of HF blood increase in the crossbred animals. The measurements of fin height, chest circumference and diagonal body length of F1, F2, F3 and HF cows raised in the experiment at 6 months of age reached values ​​in the range of 98.47 ± 0.94cm - 107.38 ± 0.88cm, 122.53 ± 0.93cm - 128.48 ± 0.85cm and 108.13 ± 0.64cm - 116.71 ±

0.62cm. At 24 months of age, it was between 127.69 ± 1.10cm – 136.41 ± 1.18cm, 175.70 ± 1.49cm – 181.23 ± 1.37cm and 145.81 ± 1.32cm –

153.72 ± 0.71cm respectively.

The body length, body roundness and weight indexes of F 1 , F 2 , F 3 and HF cows at 6 months of age were respectively: 110.01 ± 0.89 – 108.77 ± 0.76, 113.36 ± 1.02 –

110.13 ± 0.89 and 124.59 ± 1.20 – 119.78 ± 1.24. At 24 months of age, the indices

This achieved: 114.39 ± 1.16 – 112.87 ± 1.15, 120.72 ± 1.62 – 117.90 ± 0.91and

137.72 ± 1.39 – 133.12 ± 1.31 respectively.

Dimensions and body composition indexes are specific manifestations of the growth and development process of cattle. The results showed that the body length, body roundness and weight indexes of experimental cattle tended to be slightly lower and inclined towards milk production.

The coefficient of variation of the measurements and body composition indexes of the experimental cattle groups were lower than those of the monitoring cattle group, demonstrating that the experimental cattle group had more stable body composition indexes.

The dimensions and body composition indexes of the monitored and experimental cattle groups did not differ significantly. This shows that HF ​​cattle and their crossbreds raised in Lam Dong province grew and developed quite well.

Regarding body structure indexes, Tran Trong Them (1986)[89] reported that the body length index of 1/2, 3/4, 3/8 and 11/16 HF cows at Phu Dong Farm -

Hanoi is in the range of 122.45 - 129.78; the roundness index is 105.6 - 113.25. Thus, our results are lower in body length index but slightly higher in body roundness index. According to the published data of Nguyen Quoc Dat (1999) [29], the body length and roundness index of the F 1 , F 2 and F 3 cow groups raised in Ho Chi Minh City are in the range of 113.9 - 114.7 and 118.9 - 120.8, so our results are equivalent.

Thus, our results on body length and roundness indexes of F1, F2 and F3 cattle groups raised in Lam Dong province are consistent with the research results of the above authors.

3.1.2.3 Describing the growth of cattle groups using the Gompertz function

With the data set of monitoring and experimental raising on the growth of HF cow groups and crossbreds F 1 , F 2 , F 3 between HF cows and Sind crossbred cows, using the residual sum of squares method of Levenberg (1994) [151]], Marquardt (1963) [157], we described the growth of cow groups using the Gompertz function through the nonlinear regression procedure of STATGRAPHICS Centurion XV Version 15.1.02 software.

The results of the estimated calculations of the parameters m, a and b of the regression equation on the growth of the groups of cows monitored and raised experimentally are presented in Table 3.9; 3.10 and represented by Figures 3.5; 3.6; 3.7; 3.8;

3.9; 3.10; 3.11 and 3.12.

The results obtained in Table 3.9 show that in the group of monitored cows, the growth of F1 cows has the following regression equation:

Y 1 = 420.80EXP[- 2.37EXP(- 0.105x)]

With the coefficient of determination of the growth curve of this function is: R 2 = 98.30%.