Judul: Evaluation of Feed Consumption and Nutrient Adequacy of Different Breed Bulls at Artificial Insemination Centre - Lembang
Abstrak: Riset ini dilakukan untuk mengevaluasi konsumsi pakan dan kesesuaian nutrien sapi pejantan berbagai bangsa di Balai Inseminasi Buatan (BIB) Lembang. Riset dilakukan selama empat bulan dengan menggunakan data sekunder yang dicatat oleh Balai Inseminasi Buatan Bandung selama tahun 2021. Data yang digunakan meliputi: jumlah dan bangsa sapi pejantan, jenis hijauan pakan, kualitas hijauan pakan, kualitas konsentrat, kualitas hay, jumlah konsumsi dalam bahan kering, jumlah konsumsi protein dan TDN. Data merupakan hasil pencatatan bulanan selama satu tahun. Konsumsi bahan kering setiap jenis pakan baik hijauan maupun konsentrat dijadikan sebagai dasar penentuan jumlah konsumsi protein dan TDN. Bangsa sapi dibagi menjadi dua kelompok, yaitu sapi pejantan tipe besar (large type) dan tipe kecilsedang (small-middle type). Hasil penelitian menunjukan bahwa rataan konsumsi bahan kering harian (hijauan pakan dan konsentrat) berdasarkan persen bobot badan sapi adalah tipe besar adalah : FH (1,93), Angus (1,97), Brahman (1,91), Limousin (2,03), dan Simental (2,13) sedangkan tipe kecil-sedang adalah : Ongole (2,16), Madura (2,49), Wagyu (2,63), Pasundan (2,58) dan Aceh (3,30). Konsumsi protein berdasarkan tipe sapi adalah tipe besar : FH (2,47), Angus (2,17), Brahman (2,12), Limousin (2,18), dan Simental (2,15) sedangkan tipe kecil-sedang adalah : Ongole (1,97), Madura (1,93), Wagyu (1,94), Pasundan (1,90) dan Aceh (1,89). Konsumsi TDN berdasarkan tipe sapi adalah tipe besar : FH (10,56), Angus (9,33), Brahman (9,08), Limousin (9,33), dan Simental (9,23) sedangkan tipe kecil-sedang adalah : Ongole (8,46), Madura (8,30), Wagyu (8,36), Pasundan (8,16) dan Aceh (8,15). Simpulan penelitian adalah tercukupinya jumlah konsumsi pakan dan asupan nutrien pakan berdasarkan standar NRC dengan neraca kelebihan konsumsi protein untuk sapi tipe besar adalah 0,92-1,14 kg dan sapi tipe kecil-sedang adalah 0,95-1,09 kg; sedangkan neraca kelebihan konsumsi TDN untuk sapi tipe besar adalah 2,33-3,26 kg dan sapi tipe kecil-sedang adalah 2,87-3,81 kg.
Keyword: artificial insemination center, bulls, feed consumption, nutrient adequacy

Judul: Kecukupan Nutrien Makro pada Sapi Pejantan di Balai Inseminasi Buatan Lembang Jawa Barat
Abstrak: The shortage of replacement stock is a limiting factor in development of dairy and beef industry in Indonesia. Availability and performance of the replacement stock is influenced by feed availability and feeding management. The objective of this study was to evaluate the nutrient sufficiency in Bulls reared in the Institute for Artificial Insemination (BIB), Lembang - West Java. Information on feeding management, physiological condition and semen production recorded from 75 bulls was evaluated. The breed of bulls were Frisian Holstein (FH), Limousine, Simmental, Angus, Brangus, Brahman, and Ongole. They varied in their age and body weight. Feed offered were elephant grass, sugarcane top, hay, tauge and concentrate. Total feed offered was based on the body weight. Result indicated that the makro nutrients in the rations offered to the bulls was inacxess. Bulls produce high quality semen, therefore the bull has obtained the sufficient ammount of nutrient for reproduktif and milk production. Health problem of bulls was assciated with the inbalance nutrient intake.
Keyword: 

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.
Keyword: