Uğur Serbester

Effect of somatic cell count on milk yield and composition of first and second lactation dairy cows

This study was carried out to investigate the effect of somatic cell count (SCC) on milk yield and milk composition in first and second lactation Holstein dairy cows. Thirty cows in first lactation and 49 cows in second lactation were used in the study. Animals were 15±9.87 days in milk. Individual milk samples were collected monthly from June 2009 to March 2010, and somatic cell counts, milk protein, milk fat, lactose and milk urea-N were determined. Four SCC groups were formed for determining effect of SCC on milk yield and composition. These groups were as follows: ≤200, 201-500, 501-999, and ≥1.000×103 cell/mL. It was observed that SCC had a high significant effect on milk yield, milk protein, milk lactose (P<0.01), total solids and milk urea-N (P<0.05), however, the effect of SCC on milk fat was not significant (P>0.05). This study indicates that high SCC negatively affects not only milk yield but also milk composition and quality.

Comparison of yield, nutritive value, and in vitro digestibility of monocrop and intercropped corn-soybean silages cut at two maturity stages

Limited information on nutrient composition and in vitro digestibility of corn-soybean intercropped silage is available. The objective of this study was to compare corn (Zea mays L.) or soybean (Glycine max L. Yesilsoy) monocrop silage with corn-soybean intercropped silages in term of yield, nutritive value, and in vitro digestibility. Intercropping was as follows: 1 row corn to 1 row soybean (1M1S), 1 row corn to 2 rows soybean (1M2S) and 2 rows corn to 1 row soybean (2M1S). The crops were harvested when the corn reached 3/5 or 1/4 milk line. The silage samples were analysed for pH, dry matter (DM), crude protein (CP), ether extract (EE), neutral (NDF) and acid detergent fibre (ADF), calcium, potassium, magnesium and phosphorus. Also, in vitro true (IVTD) and in vitro NDF (IVNFD) digestibilities were determined in the silages samples. The DM, EE, calculated non structural carbohydrate values were higher in silage harvested at 1/4 than 3/5 milk line. All intercropped silages had higher CP values (1M1S, 8.3%; 1M2S, 10.1%; 2M1S, 8.0%) than the monocrop corn (SM, 6.8%) silage. The NDF and ADF levels were higher for 1M1S, 2M1S and SM compared with 1M2S and monocrop soybean (SS) silage. In vitro true DM digestibility of all silages increased with maturity stage; it was higher for the 1M2S than other silages. It is concluded that corn-soybean intercropped silage has better nutrient composition and digestibility than SM or SS silage.