the effects of somatic cell count (SCC), parity and lactation stage on the milk yield and the protein, fat, lactose .... that in the last stage of lactation, the milk protein.
Research Article
Harran Üniv Vet Fak Derg, 5 (1) 34-39; 2016
Effects of Somatic Cell Count, Parity and Lactation Stage on Yield and Components of Milk in Holstein-Friesian Cows Ayşe Deniz ÇARDAK Adnan Menderes University, Faculty of Agriculture, Department of Dairy Technology, Aydin, Turkey. Geliş Tarihi: 25.02.2016
Kabul Tarihi: 25.04.2016
Abstract: In this study, 1200 records from 126 Holstein-Friesian cows (first and second lactation) were used to investigate the effects of somatic cell count (SCC), parity and lactation stage on the milk yield and the protein, fat, lactose and urea nitrogen contents of the milk. In the second lactation, it was found that the milk yield and the protein content of milk was approximately 6% and 1% higher, respectively, while the fat and milk urea nitrogen (MUN) contents were 4% lower and the fat to protein ratio, 6% lower. In the first period of lactation, the milk yield was seen to be about 11% and 54% higher than that of the second and third period, respectively. In the last period of lactation, it was observed that the protein and fat content of milk was 8% and 10% higher than that of the first period and 5% and 8% higher than that of the second period, respectively. Finally, it was determined that milk yield, lactose and the MUN contents were about 12%, 10% and 17% higher, respectively, when the SCC was ≤200,000, compared to when the SCC was ≥1,001,000, and that the protein content of milk was 4% lower. Keywords: Milk Urea Nitrogen, Somatic Cell Count, First and Second Lactation, Holstein Cattle
Siyah-Alaca İneklerde Somatik Hücre Sayısı, Laktasyon Sırası ve Döneminin Süt Verimi ve Süt Bileşimine Etkileri Özet: Siyah-Alaca sığırlarda somatik hücre sayısı (SHS), laktasyon sırası ve döneminin, süt verimi ve sütün protein, yağ, laktoz, üre azotu içeriğine etkilerinin araştırıldığı çalışmada birinci ve ikinci laktasyondaki 126 ineğe ait 1200 veri kullanılmıştır. İkinci laktasyonda süt verimi ve sütün protein içeriğinin sırasıyla yaklaşık %6 ve %1 oranında daha fazla; yağ ve üre azotunun %4, yağ-protein oranının ise %6 daha az olduğu belirlenmiştir. Laktasyonun ilk döneminde süt verimi ikinci ve üçüncü döneme göre sırasıyla yaklaşık %11 ve %54 oranında yüksek bulunmuştur. Laktasyonun son döneminde sütün protein ve yağ içeriğinin ilk döneme göre sırasıyla % 8 ve %10; ikinci döneme göre sırasıyla %5 ve %8 oranında yüksek olduğu görülmektedir. SHS’nın ≤200.000 olduğu grupta süt verimi, sütün laktoz ve üre azotu içeriği SHS’nın ≥1.001.000 olduğu gruba göre sırasıyla yaklaşık %12, %10 ve %17 oranında fazla; sütün protein içeriğinin %4 oranında az olduğu belirlenmiştir. Anahtar Kelimeler: Süt Üre Azotu, Somatik Hücre Sayısı, Birinci ve İkinci Laktasyon, Laktasyon Dönemi
Introduction Milk is regarded as a staple food by nutrition physiologists, due to its combination of vital nutritional ingredients. Milk fat, which positively affects the physical properties of dairy products, is responsible for improving the taste of dairy products, while milk protein is of significant importance, in terms of nutritional value, owing to the fact that it is the basic ingredient (e.g. cheese) and the most essential component (e.g. yoghurt, concentrated milk and dried powder milk) of dairy products. For these reasons, protein and fat contents function as the key determinants for pricing milk in some countries, with premium prices being paid for milk that has high protein content. Milk yield and composition change according to the breed of livestock, lactation period, age of livestock, physical condition of the livestock, climatic conditions, nutrition and various other factors (Lindmark-Mansson et al., 2000).
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Worldwide, approximately 83% (635,575,895 tons) of the 768,640,663 tons of milk produced annually is obtained from cattle, according to the data provided by the Food and Agriculture Organization (FAO) (2013). The most important breed of dairy cattle in Turkey is the Holstein breed, which is responsible for providing approximately 90% of the country’s annual cattle milk production. In Germany, the records show that there are 2 million Holstein-Friesian dairy cows, whose milk production is 9097 kg in 305 days, and their fat and protein contents, 4.05% and 3.38% respectively (Anonymous, 2012). Every year new studies are being conducted on how to increase the output obtained per unit in the agriculture and livestock breeding sectors in order to meet the food requirements of the rapidly increasing world population. The choice of milk and dairy products for satisfying the animal protein requirement, so
Harran Üniversitesi Veteriner Fakültesi Dergisi Cilt 5, Sayı 1, 2016
Research Article
Harran Üniv Vet Fak Derg, 5 (1) 34-39; 2016
important for human nutrition, has fostered the increasing number of initiatives to introduce new implementations that serve to increase milk production. As a result of these new implementations, however, problems related to the reproductive efficiency of the cattle have frequently been encountered, certain metabolic dysfunctions have emerged, and furthermore, due to the breakout of various diseases, mastitis being at the forefront, some of the animals are forced to be isolated from the cattle herds (Richardt, 2000). The protein and fat contents of milk, which are particularly important variables for the dairy industry, serve as significant markers for identifying certain important nutrition and herd management problems, as well as for providing information about the level of success of nutritional regimens introduced to the dairy cattle. For example, the protein and fat content is able to provide information about the fat to protein ratio, the presence of metabolic dysfunctions, such as acidosis and ketosis, the energy level and level of available crude protein in feed, MUN, the level of indigestible protein in the feed and the nitrogen balance in the rumen. MUN, which is an indicator of the relation between feed protein content and energy level, also reveals information about the utilization of crude protein in the feed (Jonker et al., 1999; Godden et al., 2001b; Richardt, 2004). Nitrogen balance in the rumen has a close relation with MUN in the German nutrition system. These different variables help to determine the presence of sub-clinical ketosis in cases where the fat to protein ratio of milk is ≤1.1 and the acidosis is ≥1.5. It should be noted, however, that no changes will be observed in the fat to protein ratio of milk in cases where acidosis and ketosis take place at the same time (for example, in cases where feed rations are rich in sugar and starch and there is low feed consumption at the beginning of lactation period) (Richardt, 2000). It has been reported that under proper nutrition conditions, the optimum amount of MUN, which constitutes 2.5-3% of the total nitrogenous substances in the milk, should be between 15-30 mg/dl (Hamann and Krömker, 1997). In this study, the aim was to determine the effects of SCC, parity and lactation stage in Holstein-Friesian cattle on milk yield and the protein, fat, lactose and MUN contents in the milk, and to define the strategies needed to secure the improvement of these factors, all of which have a direct effect on the quality of dairy products.
Materials and Methods The data for this study was collected between 2012 and 2013 from 126 Holstein-Friesian cows
belonging to two farms located in Stuttgart, Germany, on the days when the milk was checked individually on a monthly basis. Milk protein, fat, lactose and MUN contents were determined using the Near Infrared Spectroscopy (NIR) (MilkoScan FT6000, Foss Electric, Denmark), and the SCC was determined using the Flow Cytometry Fossomatic 5000, Foss Electric, Denmark). The least square method was employed in order to examine the effects of SCC, parity and lactation stage on milk yield and the milk protein, fat, lactose and MUN contents. To compare the means in the subgroups, the Student-t test was used. In this regard, parity was divided into two groups, with the first group comprising cattle giving birth to their first calf, and the second group comprising those calving for the second time; lactation stage was divided into three groups, as 6-105 days, 106-205 days and more than 205 days; SCC was divided into four groups, as those ≤200,000, between 201,000-500,000, between 501,000-1,000,000, and ≥1,001,000 (Mundan et al., 2015). Statistical analyses were performed using SPSS software (Version 17.0).
Results The means (± standard deviation) related to milk yield, the protein, fat, lactose and MUN contents and the fat to protein ratio are provided in Table 1, together with their maximum and minimum values. Table 2 presents the means (± standard error), obtained using the least square method, for milk yield, the protein, fat, lactose and MUN contents and fat to protein ratio. And finally, in Table 3, the correlation coefficients for the variables have been given. The effects of parity and lactation stage on milk yield, the protein, fat, lactose and MUN contents and the fat to protein ratio were found to be significant (P
