Cows are ruminants that have a high ability to convert feed that cannot be used by humans into nutrients such as milk and meat. Milk is defined as the fluid produced by the glands of mammals and is the first food consumed by newborns immediately after birth [1]. Milk and its derivatives are an important source of protein, fat and energy and are considered a part of the daily diet. Cows contribute 85% of the global milk production [2]. In 2003, the number of foreign dairy cows in Iraq reached 30,000 thousand heads, accounting for 2.11% of the total number of 1,425 thousand heads [3].

Simmental cattle are dual-purpose cattle. These cattle come from the Sime region of Switzerland, where the Romans brought them between the third and fifth centuries AD. In addition to providing a suitable environment in their homeland, they also helped spread the monasteries and breeders. The selection process began in the 15th century until the first club of the breed was established in the city of Bern. These cattle make up half of the Swiss livestock population and have migrated to most European countries and are used to feed local cattle [4]. The Simmental cattle are a cross between large German cattle and small Swiss cattle. The breed is sought after for its fast growth and excellent milk, butter and cheese production. It was also used as a working animal for pulling or drafting [5]      .

The total milk production of Simmental cows in Germany in 2006 was 6854 kg for a season of 316 days with a fat percentage of 4.14%, a protein percentage of 3.48%, a fat quantity of 284 kg and a protein quantity of 239 kg. In the same year, its production in Croatia was 445 kg for a season of 305 days, with a fat percentage of 4.07%, a protein percentage of 3.35%, a fat quantity of 181 kg and a protein quantity of 149 kg [6]. Milk production and composition are affected by a set of factors including breed, season, age, sex of the calf, production stage, environmental conditions, health status and other factors [7-10].

Due to the lack of studies and research on Simmental cows in Iraq, this study aims to evaluate the productive performance of Simmental cattle in central Iraq by monitoring their production path during the milk season and knowing the daily and monthly milk production quantity and knowing the composition of milk and the proportions of its components, as well as evaluating the seasonal effect on milk production and its components for these cows.

This study was conducted in Iraq, Qadisiyah Governorate, Diwaniyah District, Taj Al-Nahrain Dairy Cow Breeding Station, 180 km from Baghdad for the period from 31.07.2023 to 01.06.2024. To evaluating the productive performance of Simmental cows in central Iraq by following their production path during the milk season and knowing the daily and monthly production quantity, as well as knowing the percentages of milk components and its composition and evaluating the seasonal effect on milk production and composition. In this study, 11 Simmental dairy cows were used at the beginning of their milk production and in their first production season. The cows are fed concentrated feed consisting of barley, wheat bran, wheat flour, rice flour, yellow corn, rice husk, soybean meal, in addition to salts, vitamins and minerals. The feed content is not less than 15% crude protein and the percentage of total digestible nutrients TDN ranges between 70-75%. The green fodder consists of barley, clover, hay and white corn according to their availability. In winter, hay, hay, concentrated fodder and green fodder are provided. Concentrated fodder is given according to the cow's productivity at a rate of 1 concentrated fodder for every 2 kg of milk produced. Green and dry fodder are given according to body weight, and water is available 24 hours a day. The station animals are subject to a health and preventive program under the supervision of veterinarians.

Daily milk production kg was measured by following up on milk production records for each cow, which included 11 records. Milk samples were taken twice a month to measure the percentage of milk components, with a volume of 100 ml for each sample. The samples were kept in a box containing crushed ice to protect the samples from spoilage until they reached the laboratory. Milk components were estimated using a German-made Lacto Flash Funke Gerber device. The amount of fat and protein in the milk were estimated according to Al-Qudsi and Elia, 2010. The monthly milk production percentage and the percentage of the herd's persistence index for milk production Laction Persistency Index LP were calculated according to [11]. 

The data were statistically analyzed using the ready-made statistical program SPSS 2006 and the significance of the averages was tested using the LSD test.

Results and discussion

It is noted from Figure 1 and Table 1 that the highest value of daily and monthly milk production was in the third month of the milk season, and the average daily and monthly production and the percentage of monthly production from the total production were 1.94±16 kg, 58.34±480 kg, 13.81%. then it began to gradually decline until it reached the lowest value of the average daily and monthly milk production in the tenth month of the milk season, where the average daily and monthly production and the percentage of monthly production were 1.48±5 kg, 44.49±150 kg, 4.31%, respectively.  

Figure 1: Production Months and Milk Production Quantity

Table 1: Monthly Trends in Milk Production and Composition Parameters of the Herd

This result is consistent with Shevhuzhev et al., 2017 who indicated that the highest value of milk production for Austrian Simmental cows selected for milk production milk-meat, meat-milk was in the third month of the milk season and the lowest value was in the tenth month of the milk season. The herd persistence index L.P was more than 90%, which means that the persistence trait is very good to excellent and the shape of the milk curve is almost flat Saleh et al., 1989. The total milk production value of the herd averaged 305 days was 3564.90 kg, and this result is close to what Hadad 2020 and Shevhuzhev et al., 2017 reached. The highest average percentage of fat, protein and non-fat solids was in the tenth month of the milk season and the averages were 0.33± 4.25, 0.16± 3.24, 0.42±8.76 respectively. While the lowest average value of fat, protein and non-fat solids was in the third month of the milk season and the averages were 0.20±3.92, 0.18±2.99, 0.41±8.08 respectively. While the highest average of lactose was in the third month of the milk season where it was 0.56±4.90, and the lowest average of lactose was in the tenth month of the milk season where it was 0.10±4.52 respectively. It is noted that the percentages of milk components for this study were within the normal range of milk components for this breed and are close to what was mentioned by [5,6,12,13].

Table 1 Average standard error of daily and monthly milk production, main milk components, monthly production percentage, persistence index, and total milk production adjusted to 305 days.

Table 2 shows a strong significant negative correlation p<0.05 between the monthly milk production quantity and the percentage of fat, protein, and solid non-fat materials. The correlation coefficient value between the monthly milk production quantity and the percentage of fat, protein, and solid non-fat materials was 0.97152-, 0.91478-, 0.96468-, respectively. This result is consistent with Farhomand [14] and Zhila et al., [15] and Veena et al., [16]. This may be due to the existence of an inverse relationship between the percentage of fat, protein, and solid non-fat materials and the amount of milk production Al-Qudsi and Elia, [4]. The correlation between the amount of milk production and the percentage of lactose sugar was positive and insignificant p<0.05 and the correlation coefficient was 0.587624 respectively. This result is consistent with Patbandha et al., [17] Mahdi, [18].

The reason may be that the concentration of lactose sugar increases slightly with the increase in milk production and decreases slowly at the end of the production season [19].

Table 2: The Relationship Between the Amount of Milk Production and the Main Components of Milk

Non-significant: NS;P<0.01:**;P<0.05:*

It is noted from Table 3 that the highest average of fat yield and protein yield was in the third month of the milk season and the averages reached 4.79±20.32, 2.27±13.68 kg, while the lowest average of fat yield and protein yield was in the tenth month of the milk season and the averages reached 0.93±6.85, 0.82±5.45 kg, respectively.

Table 3: Average ±Standard Error of Monthly Fat and Protein Intake

From Table 4, it is noted that there is a strong positive correlation p<0.05 between the amount of milk production and the fat yield and protein yield. The value of the correlation coefficient between the amount of milk production and the fat yield was 0.985038.

While the value of the correlation coefficient between the amount of milk production and the protein yield was 0.962816, respectively. This result is consistent with [20] who indicated that the fat yield and protein yield in milk increase with the increase in the amount of milk production.

Table 4: The Relationship Between Milk Production Quantity, Fat Yield and Protein Yield

Non-significant: NS;P<0.01:**;P<0.05:*

It is noted from Table 5 that there is a significant effect of the season on daily and monthly milk production, as autumn significantly outperformed summer, winter, winter and spring, and the average daily and monthly milk production in summer was 1.05±14.07, 31.75±422 kg. Winter also significantly outperformed summer and spring in daily and monthly milk production, and the average daily and monthly milk production for winter was 0.80±11, 24±330 kg, while there were no significant differences p<0.05 between summer and spring in daily and monthly milk production. This result is logical, as after a hot and harsh summer, the weather moderates and temperatures gradually decrease, which provides a suitable environment for increasing milk production. As the increase in temperature causes a decrease in milk production directly and indirectly through its effect on feed intake [21-22]. Milk production is also higher during the rainy season due to the high levels of energy, protein and minerals available to dairy cows during this period Gimbi, 2006. This may be due to the increase in temperature, which leads to a decrease in milk production and a decrease in feed consumption as a result of the decrease in the secretion of the hormone thyroxine, which causes a deterioration in the animal's appetite as a result of heat stress [23]. This result is consistent with [24-26]. From Table 5, it is noted that there is a significant effect p<0.05 of the season on the percentages of the main components of milk, as the summer season was significantly superior p<0.05 in the percentage of fat over the fall and winter seasons, and the average percentage of fat for the summer season was 0.33±4.23, and no significant differences p<0.05 were noted between the summer and spring seasons in the percentage of fat. There were no significant differences p<0.05 between the spring, winter and fall seasons in the percentage of fat.

Table 5: Average ±Standard Error Effect of Season on Daily and Monthly Milk Production and Main Milk Components

Non-significant: NS;P<0.01:**;P<0.05:*

Summer was significantly superior p<0.05 to autumn in the percentage of protein, as the average percentage of protein in summer was 0.17±3.22. There were no significant differences P<0.05 between summer, winter and spring in the percentage of protein. Spring was significantly superior P<0.05 to autumn in the percentage of protein.

Summer was significantly superior p<0.05 to autumn in the percentage of lactose, as the average percentage was 0.041±4.88, while there were no significant differences P<0.05 between summer, winter and spring in the percentage of lactose. Spring was significantly superior P<0.05 in the percentage of lactose, and the average percentage was 0.04±4.83, respectively.

In the percentage of non-fat solids, summer was significantly superior P<0.05 to autumn and winter, and the average percentage for summer was 0.011±8.72. There were no significant differences p<0.05 between summer and spring in the percentage of non-fat solids. Spring was significantly superior p<0.05 to winter and autumn in the percentage of non-fat solids, and the average percentage of non-fat solids for spring was 0.072±8.64, respectively. There were no significant differences p<0.05 in the percentage of non-fat solids between autumn and winter. The percentages of the main milk components increased during summer and spring, and this may be due to the decrease in the percentage of water and other components in seasons where the temperature rises [27]. The results of this study were in complete and partial agreement with [15,25-26].

1. Harding, F. Milk quality. 1st ed., Blackie Academic and Professional and Improvement of Chamman and Hall Wester and Cleddens, 1995.

2. Gantner, V. and P. Mijić. “The overall and fat composition of milk of various species.” Mljekarstvo, vol. 65, no. 4, 2015, pp. 223–231.

3. Arab Organization for Agricultural Development. “Yearbook of Arab Agricultural Statistics – League of Arab States.” vol. 22, section six, 2007, p. 121.

4. Al-Qudsi, N.H. and J.V. Elia. Dairy cattle production. Department of Animal Resources, College of Agriculture, University of Baghdad, 2010.

5. Shevhuzhev, A. et al. “Milk productivity of Simmental cows Austrian selection.” Engineering for Rural Development, Jelgava, 2017, pp. 24–26.

6. Ozhan, M. et al. “Cattle husbandry.” Ataturk University Agricultural Faculty Publication, no. 134, Erzurum, Turkey, 2015.

7. P. Skalicki et al. “Simmental cattle breed production systems.” Biotechnology in Animal Husbandry, vol. 25, no. 5–6, 2009, pp. 315–326.

8. Bucci, U.N. et al. “Animal research.” Animal Research, vol. 51, 2002, pp. 25–33.

9. Rashidi, A. et al. “Genetic parameter estimates of preweaning growth traits in Kermani sheep.” Small Ruminant Research, vol. 74, 2008, pp. 165–171.

10. Yavarifard, R. et al. “Estimation of genetic parameters for reproductive traits in Mehraban sheep.” Czech Journal of Animal Science, vol. 60, 2015, pp. 281–288.

11. Al-Fayad, M.A.J. “Seasonal variation affects the quantity and composition of milk produced in water buffaloes: case study in Shatrah city of Iraq.” J. Glob. Innov. Agric. Sci., vol. 11, no. 1, 2023, pp. 23–26.

12. Saleh, A.A.T. and A.D. Younis. Dairy cattle. Directorate of Dar Al-Kutub for Printing, University of Mosul, Iraq, 1989.

13. Bigler, A. “Performance increased further: Weitere Auswertungen im Geschaftsjahr 2000/2001, Leistungen weiter gestiegen.” Schweizer Fleckvieh, vol. 7, 2001, pp. 37–43.

14. Farhomand, P. Buffalo production. Urmieh University Publication, 2001.

15. Zhila Toopchi Khosroshahi, et al. “Effects of non-genetic factors in milk production and composition in East Azarbaijan native buffaloes of Iran.” Animal Science, University of Tabriz, vol. 30, no. 3, 2011, pp. 202–209.

16. Veena, N. et al. “Factors affecting milk yield, milk composition, and somatic cell count in dairy cattle.” Indian Journal of Animal Sciences, 2020.

17. Patbandha, T.K. et al. “Effect of season and stage of lactation on milk components of Jaffrabadi buffaloes.” The Bioscan: An International Quarterly Journal of Life Sciences, vol. 10, no. 2, 2015, pp. 635–638.

18. Mahdi, L.A. “Effect of lactation stage and calf sex in some milk components in Iraqi riverine buffalo.” Kufa Journal for Veterinary Medical Sciences, vol. 5, no. 1, 2014.

19. Friggens, N.C. et al. “On the use of milk composition measures to predict the energy balance of dairy cows.” J. Dairy Sci., vol. 90, 2007, pp. 5453–5467.

20. Hassooni, H.A. and S.F.Abboud. “Effect of different ratios of food feeding flaxseed Holstein cows milk production and component.” AL-Muthanna Journal of Agricultural Sciences, vol. 2, no. 1, 2014.

21. West, J.W. “Effects of heat stress on production in dairy cattle.” Journal of Dairy Science, vol. 86, no. 6, 2003, pp. 213–2144.

22. Nkenwa, D.D. “A study on assessment of feeding practices and performance of dairy cattle in Kibaha district, Tanzania.” MSc Dissertation, Sokoine University of Agriculture, Morogoro, Tanzania, 2009.

23. Hurley, W.L. “Lactation biology.” University of Illinois, Urbana-Champaign, 2003. Available at: http://classes.aces.uiuc.edu/AnSci308/intro.html.

24. Rosen, S. “Heat stress management in Israel.” www.israeldairy.com, 2003.

25. Bahashwan, S. “Effect of cold and hot seasons on fat, protein and lactose of Dhofari cows milk.” Net Journal of Agricultural Science, vol. 2, no. 1, 2014, pp. 47–49.

26.   Marai, I.F.M. et al. “Physiological traits as affected by heat stress in sheep – a review.” Small Ruminant Research, vol. 71, 2007, pp. 1–12.

27. Al-Fayad, M.A.J. “Relationship between ambient temperature, relative humidity with some physiological parameters, milk production and composition in cross cows.” Master’s Thesis, College of Agriculture, University of Basrah, 2015.

28. Al-Kalabi, D.Sa.K. “Predicting productive and physiological performance based on the thermal tolerance coefficient in Awassi sheep.” Master’s Thesis, Al-Musayyab Technical College, 2013.