Judul: The Status of DCAD Ration and It’s Relationship with Milk Production and Metabolic Disorders in Lactating Dairy Cows on Public Farms in Bogor.
Abstrak: Ketosis merupakan gangguan metabolik yang sering menyerang sapi perah laktasi dan berpotensi menurunkan produksi susu. Gangguan ini dapat dicegah dengan mengatur DCAD (Dietary Cation Anion Difference) ransum. Penelitian ini bertujuan mempelajari manajemen DCAD pada sapi laktasi yang dipelihara di wilayah Bogor (Kebon Pedes dan KUNAK) serta mengevaluasi hubungannya dengan produksi susu dan kejadian gangguan metabolisme dari 15 peternak di setiap wilayah. Hasil penelitian menunjukkan DCAD ransum 100% positif dengan kisaran wilayah Kebon Pedes 4,2, Ketosis is a metabolic disorder that often affects lactating dairy cows and can potentially reduce milk production. This disorder can be prevented by adjusting the DCAD (Dietary Cation Anion Difference) in the diet. This study aims to investigate DCAD management in lactating cows raised in the Bogor area (Kebon Pedes and KUNAK) and evaluate its relationship with milk production and the incidence of metabolic disorders among 15 farmers in each area. The study results showed that the DCAD in the diet was 100% positive, with the range for Kebon Pedes being 4.2±187.4 100 kg-1 DM and for KUNAK 54.52±217.06 100 kg-1 DM. A positive DCAD is necessary during the lactation period. Milk production in Kebon Pedes was 13.67 day-1 cow-1 , while in KUNAK, it was 15.87 day-1 cow-1 . The incidence of ketosis was observed in 13% of cows in Kebon Pedes and 6% in KUNAK. ANOVA analysis of both areas showed that livestock performance and production in KUNAK (landbase) were better than in Kebon Pedes (landless). Based on these findings, it can be concluded that DCAD management in KUNAK is better, thus feed management improvement is needed, especially in Kebon Pedes, to increase milk production and reduce metabolic disorders
Keyword: DCAD

Judul: Evaluasi Status  Mineral DCAD Pakan Sapi Perah Pre-partum dan Post partum di KPSBU  Lembang
Abstrak: Sapi pada masa transisi seringkali mengalami penurunan daya tahan tubuh akibat adanya perubahan fisiologis dan metabolik pada tubuh sapi. Salah satu penyakit yang sering ditemui pada sapi pada masa transisi adalah hipokalsemia. Gangguan metabolisme pada sapi transisi dapat diatasi menggunakan DCAD (Dietary Cation Anion Difference). Peubah yang diamati berupa kandungan nutrien pakan, pemberian dan kecukupan pakan, kandungan mineral pakan, status DCAD pakan serta hubungannya dengan performa ternak. Rasio pemberian pakan di KPSBU pada sapi pre-partum 50:50 dan post-partum 54:46. Kecukupan nutrien di KPSBU sudah hampir memenuhi seluruh kebutuhan ternak. Status DCAD sapi transisi di KPSBU masih belum sesuai saran pemberiannya dimana DCAD sapi pre-partum adalah (4,2±211) sementara DCAD sapi post-partum adalah (-42,0±170,3). Rata-rata produksi susu harian di KPSBU adalah 17 L/hari. Gangguan metabolik pada sapi pre-partum sebesar 13,3% dan post-partum sebesar 46,7%. Reformulasi ransum, penambahan mineral pada pakan berupa pakan aditif atau garam kationik dan anionik diharapkan dapat memperbaiki status DCAD sapi transisi di KPSBU., Cows during the transition period often experience a decrease in body resistance due to physiological and metabolic changes in the cow's body. One disease that is often encountered in cows during the transition period is hypocalcemia. Metabolic disorders in transitional cows can be overcome using DCAD (Dietary Cation Anion Difference). The parameters observed were feed nutrient content, feed provision and adequacy, feed mineral content, feed DCAD status and its relationship with animal performance. Feeding ratio at KPSBU for cattle pre-psrtum 50:50 and post-partum 54:46. Nutrient adequacy at KPSBU has almost met all livestock needs. The DCAD status of transitional cattle at KPSBU is still not in accordance with the recommendations for granting DCAD cattle pre partum is (4.2±211) while DCAD of cattle post-partum is (-42.0±170.3). The average daily milk production at KPSBU is 17 L/day. Metabolic disorders in cattle pre-partum of 13.3% and post-partum amounting to 46.7%. Diet reformulation, adding minerals to the feed in the form of feed additives or cationic and anionic salts is expected to improve the DCAD status of transition cattle at KPSBU.
Keyword: DCAD, mineral, pakan, sapi transisi

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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