Judul: Study of feedlot optimality through manipulation of feed, compensatory growth and fattening time period
Abstrak: Usaha penggemukan sapi (Feedlot) di Indonesia pada dekade 10 tahun terakhir ini menunjukkan perkembangan yang pesat. tetapi d~ika ekonomi mak:ro yang tidak menentu akibat krisis ekonomi yang berkepanjangan saat ini, telah menimbulkan implikasi terhadap situasi yang tidak menguntungkan bagi usaha penggemukan sapi (Feedlot) schingga salah satu altematif untuk mengatasi masalah tersebut adalah mencari suatu model penggemukan sapi yang efisien. sehingga usaha penggemukan sapi dapat memberikan keuntungan yang optimal. Model penggemukan sapi yang dikcmbangkan adalah melalui manipulasi terhadap komponen yang memiliki kontribusi dominan terbadap biaya produksi dan berdampak tcrhadap peningkatan kualitas produk daging. Manipulasi dilakukan terhadap kualitas pakan, p.e-n-c-ra-p-a-n- f-c-n-om--e-na pertumbuhan kompensasi dan penentuan periode waktu pcnggemukan yang efisicn, schingga tujuan dari penelitian ini adalah ( 1) untuk mengetahui pengaruh perbedaan kualitas pakan (perbedaan kadar protein/energi), pertumbuhan kompensasi dan periode waktu penggemukan (2. 3 dan 4 bulan) terhadap kinerja pertumbuhan. produksi pemotongan (karkas dan daging) dan kualitas daging (2) untuk mencari model penggemukan sapi yang optimal, dengan cara memanipulasi pakan. Pertumbuhan kompensasi dan penentuan periode waktu penggemukan sapi dalam kombinasi perlakuan yang sinergis., The objectives of the study was to find an optimum production of fattening model through manipulation of feed, compensatory growth and fattening period. One hundred eight young catties (steers) of Australian Commercial Cross (ACC), 2-3 years old were used and 54 heads of catties were slaughtered. Those catties were devided into 3 treated groups. Group I : was treated with different ration of Crude Protein (CP)/Metaboliz.able Energy (ME)= 16,12% /2534 kcal (T); 13,52% /2392 kcal (S) and 11, l 8% /2287 kcal (R) of l kg dry matter ration. Group II : was treated with different condition of steers of thin body I compensatory growth (K) and not thin body/ non compensatory growth (NK). Average Daily Gain (ADG) ofK was more than 0,9 kg/day and NK was less than 0,9 kg/day. Group m : was treated with 3 different fattening time period of 2 months (WP 2); 3 months (WP3) and 4 months (WP4). The study was carried out on November 1997 to September 1998 at P. T. Kariyana Gita Utama f~ Cicurug, Sukabumi, West Java. P.T. Sampico Adhi Abbattoir, Tambun Bekasi, Balai Penelitian Ternak Ciawi, Bogor, Animal Product Technology Laboratory, Faculty of Animal Science and Faculty of Agriculture Technology Gadjah Mada University, Yogyakarta. Results showed that compensatory growth (K). fucreased Average Daily Gain, Feed efficiency, slaughtered weight, percentage of marbling, and unsaturated fatty acid. Different quality of ration (T, Sand R) did not indicated differences on ~owth performance and slaughtered yields. Time periods of fattening (WP 2, WP 3, WP 4) increased on slaughtered weight, dressing percentage, fat of carcass, percentage of marbling, tenderness of meat and unsaturated fatty acid. Optimum production of feedlot was reached at time period of fattening with compensatory growth and feed formulation was base upon consumption of CP and ME that adjusted to the nutrition requirement and considered to capital sirculation, preference of consumer and market.
Keyword: Feedlot, Feed, Compensatory growth, Fattening

Judul: Kinerja produksi sapi Australian Commercial Cross yang dipelihara secara feedlot dengan kondisi bakalan dan lama penggemukan berbeda
Abstrak: Penelitian bertujuan untuk mengkaji kondisi bakalan dan lama Penggemukan yang paling efektif dan efisien, sehingga diperoleh kinerja produksi sapi yang secara ekonomis mnguntungkan pada pemeliharaan secara feedlot. Delapan belas ekor sapi bakalan Australian Commercial Cross kebiri dengan bobot 301-380 kg dan kisaran umur 2-3 tahun (12-13). Percobaan menggunakan Rancangan Acak Lengkap pola Faktorial 2x3, dengan tiga ulangan. Faktor pertama adalah kondisi bakalan (kondisi kompensasi dan non kompensasi). Faktor kedua adalah lama penggemukan (2, 3 dan 4 bulan). Selama penelitian pakan dan air minum diberikan secara adlibitum. Parameter yang diamati meliputi parameter pertumbuhan berupa pertambahan bobot badan, konsumsi bahan kering, konversi pakan dan bobot potong; parameter komposisi tubuh berupa persentase karkas dan komponen karkas, persentase potongan komersial karkas (wholesale cut), persentase non karkas dan komponen non karkas serta parameter nilai ekonomis ternak berupa feed cost gain dan income over feed cost.
Keyword: Australian Commercial Cross, Feed Cost Gain, Income over feed cost

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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