Effects of Milk Quality on Growth and Development of Suckling Calves

Lina MA, Yang YU, Haihui GAO, Xiaojun LIANG

Abstract [Objectives] This study was conducted to study the effects of cows milk quality on suckling calves growth and development.

[Methods] A total of 80 regular milk samples from Simmental and Angus cows were collected to complete the detection of conventional milk components.

[Results] Under the same feeding and management conditions， the chemical composition of Simmental cows milk was better than that of Angus cows milk. High milk fat in Simmental cows milk was beneficial to calves early growth and development， and high milk protein in Angus cows milk composition was conducive to calves early weight gain.

[Conclusions] This study provides a theoretical basis for reducing calves mortality， alleviating calves stress， and improving the economic benefits of beef cattle breeding.

Key words Milk quality; Calf; High milk fat; High milk protein; Growth and development

Received： April 8， 2022  Accepted： June 9， 2022

Supported by Research on the Calf Breeding Technology （NGSB-2021-12-04）; National Modern Agricultural Industry Technology System of the Ministry of Finance and the Ministry of Agriculture and Rural Affairs （CARS-37）.

Lina MA （1985-）， female， P. R. China， assistant research fellow， master， devoted to research about livestock genetic breeding.

*Corresponding author. E-mail： 1092295523@qq.com.

Calves are the backup force of beef cattle breeding， and calves growth and development is closely related to the production performance of beef cattle in adulthood. Calves suckling period is within 3 months after birth， during which they must be breast-fed by cows due to that their digestive system is not yet fully developed and their digestive capacity is insufficient. Breast milk is the main food for calves normal growth. It should be ensured that calves are fed with their mothers until weaning to increase their survival rate， reduce their death and alleviate their stress， so as to improve the economic benefits of beef cattle breeding.

Materials and Methods

Sample collection

Forty milk samples from the third parity of the second-generation Simmental cows and 40 milk samples from the third parity of Angus cows were collected， all from Ningxia Yongning Benwang Ecological Breeding Company. The milk samples were collected from each cow at 7：00 am， 12：00 noon and 18：00 pm， mixed with preservatives， stored in ice packs and sent to the laboratory.

Calf feeding management

The calves were breast-fed with their mothers， and supplemented with feed in the early stage for 7 d， with free access to green hay and drinking water， and other feeding and management levels were kept the same. The composition of calf supplementary pellet feed， alfalfa grass and nutrient levels in the test period are shown in Table 1 and Table 2.

Measurement of calves body weight data

The birth weights of the two groups of calves were measured， and their 30-day-old， 60-day-old and 90-day-old body weights were also measured before morning feeding. The calves development was recorded.

The premix provided the following per kg of diets： VA 250 KIU， VD 60 KIU， VE 1 000 IU， Fe 80 mg， Cu 12 mg， Zn 80 mg， Mn 70 mg， Se 0.40 mg， I 1 mg， Co 0.80 mg; and the combined net energy is the calculated value， and the rest are measured values.

Routine composition determination

The determination was carried out according to the analysis method of GB5009.46. Specifically， the micro Kjeldahl method was used for protein; the Babcock method was used for fat; lactose was determined by the potassium permanganate titration method; and the direct drying method was used for non-fat milk solids.

Results and Analysis

Conventional ingredient index of milk

The chemical composition of the milk samples was determined in Table 3. The chemical composition of the milk sample from Simmental cows was better than that from Angus cows， including fat which was 75.64% higher， protein which was 9.26% higher， lactose which was 7.98% lower， total solids which was 16.95% higher， and the number of somatic cells which was 43.79% higher， minerals which was 27.12% higher， and urea nitrogen which was 59.78% lower.

Correlation analysis between main components of milk and daily weight gain of calves

The results of the birth weight and 30-day-old， 60-day-old and 90-day-old body weights of calves are shown in Table 4. There were no significant differences in birth weight and average daily gain between the two groups of calves （P>0.05）， but the 30-day-old， 60-day-old and 90-day-old body weights of Simmental calves were significantly higher than those of Angus calves （P<0.05）.

Correlation analysis between main components of Simmental cow milk and calves daily weight gain

The correlation coefficients between milk fat， milk protein， lactose and dry matter in cows milk components and calves daily weight gain were calculated. The results showed that the correlation coefficients of the main components of Simmental cows milk and calves daily weight gain ranked as milk fat （0.96）>dry matter （0.95）>milk protein （0.79）>lactose （0.60）. The correlation between milk fat of Simmental cows milk and calves daily weight gain was the greatest.

Correlation analysis between main components of Angus cow milk and calves daily weight gain

The correlation coefficients between milk fat， milk protein， lactose and dry matter in cows milk components and calves daily weight gain were calculated. The results showed that the correlation coefficients of the main components of Angus cows milk and calves daily weight gain showed an order of dry matter （0.94 g/d）>milk protein （0.92 g/d）>milk fat （0.91 g/d）>lactose （0.89 g/d）. The correlation between milk protein in Angus cows milk on calves daily gain was the largest， and according to the effect of milk protein in Angus cows milk on calves daily gain， the higher the milk protein rate of cows milk， the greater the calves daily gain.

Discussion and Conclusions

In recent years， the effects of cow milk quality on calves growth and development have become a research hotspot. The main nutritional indexes in the milk produced by the third generation of Simmental cows are significantly better than those of Holstein milk， and Simmental cows milk has better development and utilization value[1]. In Ningxia， cattle farms are generally dominated by house-raised Angus and Simmental cattle[2]， and Simmental cattle are mainly crossbred with local cattle breeds. Studies have found that the calving month has a certain relationship with the milk fat percentage. The cows calving in September-October have the highest milk fat percentage and those calving in March-April have the lowest milk fat percentage[3]. Supplementary feeding of 1 kg of corn per horse per day in the basal feed can significantly increase the blood sugar level， milk yield， milk protein percentage and lactose content of Yili horse mare， and improve milk quality[4]. Adding compound probiotics to dairy cows diets can significantly increase milk production， improve milk quality （milk fat percentage， milk protein percentage， total milk solid content， lactose）， and change the structure of intestinal flora， improve intestinal health， and the optimum dosage is 40 g/d[5]. Adding no more than 10% bacterial bran to dairy cows diet can improve milk quality and improve dairy cows antioxidant capacity[6].

In the study， a total of 80 regular milk samples from Simmental and Angus cows were collected to complete the detection of conventional milk components. It was found that under the same feeding and management conditions， high milk fat in Simmental cows milk was beneficial to calves early growth and development， and high milk protein in Angus cows milk composition was conducive to calves early weight gain.

References

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[3] ZHU GH. Effect of calving month on cows milk fat percentage[J]. Shanghai Agricultural Science and Technology， 1989（6）： 27. （in Chinese）.

[4] LI Q， DOU JJ， LI H， et al. Effects of supplementary feeding with different levels of maize on milk yield and milk quality in Yili horses[J]. Chinese Journal of Animal Science， 2021， 57（9）： 168-171. （in Chinese）.

[5] SUI M， WU YN， LI JR， et al. Effects of dietary supplementation of probiotics on production performance， milk quality and intestinal flora of dairy cows[J]. China Feed， 2021（11）： 50-54. （in Chinese）.

[6] LIU D， DING ZZ， WU ZL， et al. Effect of adding bacterium residue in diets on milk production， milk quality， blood biochemical indexes and antioxidant function of dairy cows[J]. Feed Research， 2021， 44（4）： 7-10. （in Chinese）.