Browsing by Subject "dairy cows"

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  • Sekhar, Deepa (Helsingfors universitet, 2012)
    Metabolic disorders are known to predispose dairy cows to periparturient diseases. Main components of metabolic disorder are insulin resistance and severe negative energy balance which are responsible for the reduced fertility in addition of increased risk of disease in dairy cows. The mobilization of adipose tissue in response to energy deficiency is associated with metabolic and endocrine changes during early lactation. Reduced insulin sensitivity in peripheral tissues could potentially change the relative rates of lipolysis and lipogenesis. This study focused on expression of lipogenesis and lipolysis associated genes around parturition. Samples and data sets for this study were obtained from the feeding experiments conducted from September 2010 to April 2011 in Viikki Experimental Farm at the University of Helsinki. Sixteen multiparous Ayrshire cows were divided into two groups based on energy level and fibre content of their feed: (1) grass silage group (control) and (2) silage-roughage mixture group (experiment). During experimental period average energy intake (MJ/day) in silage group was 35% higher than in silage-roughage mixture group. Subcutaneous adipose tissue samples were collected a week before, one day and a week after parturition from cows. Total RNA was extracted from tissue samples quality and quantity of total RNA was analysed using electrophoresis and spectrophotometer. Complementary DNA (cDNA) was prepared from the total RNA for quantitative PCR (qPCR). QPCR was conducted to quantitate expression of the following genes: adiponectin (ADIPOQ), leptin (LEP), peroksisome proliferator activated receptor gamma (PPAR-?), adiponectin receptor-1 (AR1), adiponectin receptor-2 (AR2), lipoprotein lipase (LPL), stearoyl-CoA desaturase (SCD) and hormone-sensitive lipase (HSL). Two genes, AR2 and LEP, were downregulated in group 1. Reduced expression of AR2 in group 1 may relate to an increased insulin resistance. The glucose metabolism was reduced further leading to reduced insulin sensitivity. Lower expression of LEP after parturition indicates usage of energy for milk production. The upregulation of SCD in group 1 before and after calving as well as after calving in group 2 may be a result of the uptake of fatty acids by the mammary tissues. The expression of ADIPOQ, AR1, LPL, PPAR, and HSL did not show any significant changes.
  • Puranen, Anni (Helsingfors universitet, 2011)
    Sodium hydroxide (NaOH) is a strong base which disrupts the seed coat by partial hydrolysis of hemicellulose and lignin in the rumen. NaOH can substitute for mechanical processing of cereal grains. Using total mixed ration including NaOH –treated grains, is an opportunity to avoid the metabolic problems caused by high dietary starch content. The objective of this study was to determine the effects of various levels of NaOH –treated wheat grains in ad libitum total mixed ration diet on feed intake and production of dairy cows. Commonly used oats-barley diet was a control. This study was conducted at the experimental farm of Swedish University of Agricultural Sciences, Umeå, Sweden from September to November 2010. There were 17 multiparous and 6 primiparous cows in the study (Swedish red breed). The cows were kept in a warm loose house barn and intake of total mixed ration was measured by using scale cups. Experimental treatments were ground barley and ground oats in the ratio of 1:1, ground wheat in the ratio of 1:0, ground wheat and NaOH –treated whole wheat in the ratio of 1:1 and NaOH –treated whole wheat in the ratio of 1:0. All the diets were formulated to have a dry matter content of 370 g/kg and crude protein content of 180 g/kg dry matter. Apparent digestibility of nutrient was determined using acid insoluble ash as a marker. Utilization of nitrogen was evaluated using calculated nitrogen balance. The experiment was conducted according to the 4x4 Latin square designs and the statistical differences between the treatments were detected by contrasts. Intakes of dry matter (PQ=0.02) and organic matter (PQ=0.02) increased in pursuance of their improved digestibility as half of the dried wheat was supplemented for NaOH –treated wheat. There was no significant difference between treatments in milk yield or energy corrected milk yield. Milk fat yield (PQ=0.04) and concentration of milk fat increased clearly (PQ=0.004) as half of the dry wheat was substituted for NaOH –treated wheat. By substituting all dry wheat for NaOH -treated wheat, milk protein concentration decreased (PL<0.001). The same occurred for milk urea concentration (PL=0.002). The NaOH –treatment did not result in any economic improvement in this study because concentration of milk protein decreased and intake increased, while milk production remained the same. The best production response was achieved by the mix diet of dried wheat and NaOH –treated wheat.