---

Abstract

The influence of age and live weight at conception on the consumption of metabolizable energy and crude protein during 6 months of pregnancy, processes of their growth and development was studied. The gain of live weight of springer heifers during the first three months of pregnancy was determined to be 67,0±3,66 kg in group I, 65,0±5,26 kg in group II and 49,0±4,40 kg in group III. Studying the growing power of the animals during 0-3 months (92 days) of pregnancy, the springer heifers of groups I and II were found to be superior to the herdmates of the group III by 196g and 174g or 26,9 and 24,4% (p<0,01) in terms of the average daily gain. Comparing the characteristics of the live weight gain at 4-6 months (92 days) of pregnancy, the springer heifers of groups I and II were found to be significantly superior to their analogues in group III by 29.0 and 28.0 kg. The springer heifers of groups I and II outweighed their herdmates of group III by 316 and 305 g or 43,4% and 47,5% (p<0,001) in terms of the average daily gain. It is necessary to underline that animals of groups I and II had higher gain of live weight during the whole experimental period by 47,0 and 43,0 kg or 58 and 53% as compared to the analogues of group III.
According to the results of multicriteria analysis, for group I the objective function was determined to be lower and was 0.0359 on the examined criteria, while the objective functions of groups II and III were worse at 1.4 and 12.1 respectively. At the same time, the animals in group II were 8.6 times superior to their analogues in group III. It indicates the superiority of animals in groups I and II with a productive mating age of 14.8-15.3 months and a live weight of 373-414 kg. They had a more intensive gain of live weight during pregnancy and spent less energy and crude protein feed per kilo of gain.
The linear, partial quadratic and partial quadratic regressions were developed to describe the correlation between the increase of live weight of heifers and their age and live weight at the time of conceiving and the consumed metabolizable energy and crude protein for 6 months of pregnancy.
The season of the year was determined to have no significant impact on the heifers’ development during the pregnancy period in the herd and their further milk productivity.

References

1. Hutchenko, H. A. (2017). Osoblyvosti kholodnoho metodu utrymannia teliat [Peculiarities of the cold method of keeping calves]. Studentskyi naukovyi visnyk MNAU– Student scientific bulletin of the Mykolaiv National Agrarian University. 2 (13), 2, 50–54 [in Ukrainian].
2. Sychova, O. O. (2009). Intensyvnist rostu molodniaku velykoi rohatoi khudoby zalezhno vid yoho morfo-funktsionalnoho statusu v neonatalnyi period [Growth intensity of young cattle depending on its morphological and functional status in the neonatal period]. Naukovyi visnyk Natsionalnoho universytetu bioresursiv i pryrodokorystuvannia Ukrainy – Scientific Bulletin of the National University of Bioresources and Nature Management of Ukraine. 138, 47–51 [in Ukrainian].
3. Prasad, Vara W .L. N. V., Srinivasa, Naik, H., Nasreen, A., Ramana, Murthy R. V., Srilatha, Ch., Sujatha, K., & Phaneedra, M. S. S. V. A. (2017). Case of Cutaneous Apocrine Adenocarcinoma in a 10 days old Buffalo calf. Journal of Livestock Science. 8, 35–37.
4. Pidpala, T. V., (Ed.) Ostapenko, O. M., Yasevin, S. Ye., Drovniak, O. V., Marykina, O. S., & Hrebeniuk, N. V. (2018). Intensyvni tekhnolohii u molochnomu skotarstvi [Intensive technologies in dairy farming]: monohrafiia. Mykolaiv, 250 [in Ukrainian].
5. Shalovylo, S. H., & Shcherbatyi, Z. Ye. (2006). Shliakhy pidvyshchennia produktyvnosti koriv u molochnomu skotarstvi [Ways to increase the productivity of cows in dairy farming]. Silskyi hospodar –  Village owner. 11-12, 3–5 [in Ukrainian].
6. Shkurko, T. P. (2012). Napravlene vyroshchuvannia remontnykh telyts molochnykh porid [Directed breeding of repair heifers of dairy breeds]. Kormy i fakty–Fodder and facts. 24, 24–27 [in Ukrainian].
7. Pankieiev, S. P., & Pylypenko, Yu. P. (2021). Perspektyvna tekhnolohiia spriamovanoho vyroshchuvannia molodniaku v molochnomu skotarstvi [Promising technology of targeted breeding of young animals in dairy farming]. Tavriiskyi naukovyi visnyk – Taurian Scientific Bulletin. 118, 260–267 [in Ukrainian].
8. Ettema, J. F., & Santos, J. (2004). Impact of age at calving on lactation, reproduction, health, and income in first-parity Holsteins on commercial farms. Journal of Dairy Science. 87, 8, 2730–2742. https://doi.org/10.3168/jds.S0022-0302(04)73400-1.
9. Lopes, G., Jr., C. Johnson, L. Mendonça, P. Silva, J. Moraes, A. Ahmadzadeh, J. Dalton, & Chebel, R. (2013). Evaluation of reproductive and economic outcomes of dairy heifers inseminated at induced estrus or at fixed time after a 5-day or 7-day progesterone insert-based ovulation synchronization protocol. Journal of Dairy Science. 96, 1612–1622. https://doi.org/10.3168/jds.2012-5971.
10. Silva, T. V., Lima, F., Thatcher, W. & Santos, J. (2015). Synchronized ovulation for first insemination improves reproductive performance and reduces cost per pregnancy in dairy heifers. Journal of Dairy Science. 98, 7810–7822. https://doi.org/10.3168/jds.2015-9704.
11. Tozer, P. R., & Heinrichs, A. J. (2001). What affects the costs of raising replacement dairy heifers: a multiple-component analysis. Journal of Dairy Science. 84, 4, 1836–1844. https://doi.org/10.3168/jds.S0022-0302(01)74623-1.
12. Gabler, M. T., Tozer, P. R., & Heinrichs A. J. (2000). Development of a cost analysis spreadsheet for calculating the costs to raise a replacement dairy heifer. Journal of Dairy Science. 83, 5, 1104–1109. https://doi.org/10.3168/jds.S0022-0302(00)74975-7.
13. Heinrichs, A. J., Jones, C. M., Gray, S. M., Heinrichs, P. A., Cornelisse, S. A., & Goodling, R. C. (2013). Identifying efficient dairy heifer producers using production costs and data envelopment analysis. Journal of Dairy Science. 96, 11, 7355–7362. https://doi.org/10.3168/jds.2012-6488.
14. Mohd, Nor N., Steeneveld, W., Derkman, T. H. J., Verbruggen, M. D., Evers, A. G., de Haan, M. H. A., & Hogeveen H. (2015). The total cost of rearing a heifer on Dutch dairy farms: calculated versus perceived cost. Irish Veterinary Journal. 68, 29. https://doi.org/10.1186/s13620-015-0058-x
15. Piskun, V. I., Yatsenko, Yu. V., & Yatsenko, Yu. Yu. (2020). The concept of optimization of technological solutions of agricultural production. Modern engineering and innovative technologies. Germany. 12, 1, 5‑11. https://doi.org/10.30890/2567-5273.2020-12-01-015.