Judul: Evaluasi Kecukupan Nutrisi Sapi Perah di Kawasan Usaha Peternakan Cibungbulang Bogor, Jawa Barat
Abstrak: The study is aimed to evaluate nutritional status of cows and their relation to animal performance at two different seasons (drought and rainy). The study was conducted in two phases. First phase was drought season data collecting for 3 months and the second phase was rainy season data collecting. The sample collected was examined in Dairy Nutrition and PAU laboratories IPB (March – June 2013). Variable was measured including the type and amount of feeds and nutrients offered, milk production and quality, body condition score. The collected data was tabulated and analyzed using descriptive statistic. Comparison between nutrients offered and standard requirement was analyzed using T-test. T-test have also been used to compare nutritional status of animal in rainy and drought seasons. The result showed that farmers in KUNAK have offered sufficient amounts of nutriens for their cows exept for Ca, when drought season came, deficiency of P was also occured. Milk yield tent to decrease during drought season but milk fat content increase during drought season but milk fat content increased. It is concluded that imbalance ration is one of the cause for low average milk production in KUNAK.
Keyword: nutrient adequacy, milk quality, milk production, dairy cows

Judul: Evaluasi Kecukupan Nutrien Sapi Perah pada Musim yang Berbeda di Koperasi Peternak Sapi Bandung Utara (KPSBU) Lembang
Abstrak: This research was aimed at evaluating dairy cows nutritional status on milk production and quality in different rainfall. The research was done from September 2012 until June 2013 for field survey and laboratory analysis. Body weight, feed intake, nutrient contents, milk production, and milk quality have been measured and analyzed. The data were analyzed using T-test to compare the differences rainfall effect, correlation between all parameters heve been tested and regression model of milk production and quality have been made based on the correlation test. The results showed that in average dairy cows kept by small holder famer under KPSBU administration has been offered feed to fulfilled their nutrients requirement,except for mineral Ca. During early rainy, milk production, lactose, protein, and solid non fat (SNF) tends to be lower, but milk quality especially fat content of milk were higher. No satisfaction regression of milk production and quality model could be made from the parameters used which show that farmers did not consider cow performance in feeding their cattle.
Keyword: nutrient adequacy, milk quality, milk production, dairy cows

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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