Judul: Pengembangan Indeks Iklim untuk Prediksi Produksi Susu Sapi Perah FH (Fries Holland)
Abstrak: Global warming that causing climate change has caused negative impact on many sectors, one of them is livestock. Temperature increase, change in humidity and rainfall pattern will affect directly and indirectly on dairy production. Direct impact of climate change is impacting metabolism which finally causes eating behavior. Indirect impact is reducing feed availability due to climate change impact on forage production. For dairy cattle, ideal climate condition is measured from climate index which is a function of temperature and humidity. This is commonly called as temperature humidity index. Dairy cattle in Indonesia are mostly from Europe, i.e. Holstein (Fires Holland). If they were exposed to high temperature and high humidity, they will in stress and it will reduce feed intake and finally milk production. In Indonesia, Holstein are fond in many locations, in low to high altitude areas with different climate condition. This study aims to evaluate climate index that can be used for predicting milk production and feed management as well as defining adaptation options for addressing potential impact of climate change on dairy production. This study was conducted in five locations with different altitude, i.e. Pondok Ranggon-Jakarta Timur (80 m asl), Kebun Pedes Bogor (215 m asl), Buni Kasih Cianjur (936 m asl), Cisarua Bogor (1111 m asl) and Cikole Lembang (1225 m asl). Data being measured included temperature (T), relative humidity (RH), cattle age and weight, feed consumption and feed composition as well as daily milk production. Climate Index being developed called as Temperature Humidity Index (THI) was calculated from the following formula THI=(1.8T+32)-((0.55-0.0055RH)x(1.8T-26.8)). The result of this study indicates that THI has significant influence on milk production of FH (Fries Holland). In addition to climate condition, dairy age (U) and weight (BB), crude protein (PK) also affect significantly milk production. Thus the milk production of FH (Y) can be estimated from the following equation Y=5.754+0.1940(U)-0.000888(U)2+0.021BB+1.166PK-0.163THI; R2=75.9%. From this analysis, it was found that the ideal THI for FH is between 74.82 and 76.82. If the THI outside of this range, the feed intake will be low and this will result in low milk production. This study suggested that possible adaptation measures to minimiza the negative effect of too high or too low HTI are by (1) lowering body temperature of the cattle by pouring it with cold water (2) modifying cattle cage construction with shading and good ventilation so that the THI will be within the optimum range, and also good waste streams system and (3) increasing feed quality, particularly when the THI cannot be modify to be at the optimum range.
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Judul: Milk Production Model Development
Abstrak: Dalam upaya meningkatkan tingkat produksi susu dalam negeri, Indonesia mendatangkan sapi perah dari Eropa. Perbedaan iklim antara daerah asal dan Indonesia diperkirakan berpengaruh besar pada produksi susu. Penelitian ini bertujuan menghitung besar pengaruh keragaman iklim dan faktor lainnya terhadap produksi susu sapi perah dan menyusun model prediksi produksi susu. Penelitian dilakukan di Kabupaten Semarang di tiga lokasi yaitu Kecamatan Getasan (1081m mdpl), Kecamatan Tengaran (702 mdpl), dan Kecamatan Ungaran Barat (418 mdpl). Data produksi susu, pemberian pakan dan minum harian sapi perah dikumpulkan melalui pengukuran langsung pada 265 ekor sapi dari Maret hingga Mei 2023. Umur sapi diperoleh dari wawancara, data suhu dan kelembaban melalui pengukuran langsung dengan thermo-hygrometer. Metode penelitian menggunakan analisis regresi. Hasil penelitian menunjukkan bahwa peningkatan produksi susu sejalan dengan meningkatnya umur. Faktor umur dapat menjelaskan keragaman produksi susu sampai 80%. Lebih lanjut keragaman produksi susu berbagai tingkat umur dipengaruhi secara nyata oleh kondisi iklim yaitu tingkat kepanasan atau kelengasan udara (Temperature Humidity Index-THI) serta jumlah konsentrat dan jumlah minum yang diberikan. Faktor ini dapat menjelaskan keragaman produksi susu pada tingkat umur sampai 20%. Hasil ini menunjukkan bahwa hampir semua keragaman produksi susu dapat dijelaskan oleh umur dan pemberian pakan/minum serta THI. Secara umum kondisi lingkungan yang nyaman bagi ternak ialah wilayah yang memiliki THI kurang dari 72. Pada THI yang tinggi sapi akan mengalami stress dan produksi susu menurun., In an effort to increase the level of domestic milk production, Indonesia imports dairy cows from Europe. The difference in climate between the area of origin and Indonesia is expected to have major effect on milk production. This study aims to calculate the effect of climate variability and other factors on milk production of dairy cows and to develop a milk production prediction model. The research was conducted in Semarang Regency in three locations, namely Getasan Subdistrict (1081 mdpl), Tengaran Subdistrict (702 mdpl), and West Ungaran Subdistrict (418 mdpl). Data on milk production, daily feeding and drinking of dairy cows were collected through direct measurement on 265 cows from March to May 2023. Cow age was obtained from interviews, temperature and humidity data through direct measurement with a thermo-hygrometer. The research method used regression analysis.The results showed that milk production increased in line with increasing age. The age factor can explain the variability of milk production up to 80%. Furthermore, the varaibility of milk production at various ages was significantly influenced by climatic conditions, namely the level of heat or air humidity (Temperature Humidity Index- THI) as well as the amount of concentrate and the amount of drinking water given. This factor can explain up to 20% of the variation milk production at age level. These results indicate that almost all of the variability in milk yield can be explained by age and feeding/drinking and THI. In general, comfortable environmental conditions for livestock are areas with THI of less than 72. At high THI, cows will experience stress so that milk production will decrease.
Keyword: milk production, multiple linear regression analysis, sapi perah, Dairy Cows, THI

Judul: Graf Pembagi-Nol Planar dan Tak-Planar
Abstrak: Graf pembagi-nol adalah suatu graf yang dibentuk dari himpunan pembaginol pada ring. Graf pembagi-nol terdiri atas himpunan simpul yang merupakan elemen-elemen pembagi-nol dari ring, serta dua simpul adjacent jika dan hanya jika hasil kalinya sama dengan nol. Graf pembagi-nol dapat digambarkan dalam sebuah bidang sedemikian rupa sehingga tidak ada dua sisi yang saling berpotongan. Graf pembagi-nol ini disebut sebagai graf planar. Karya ilmiah ini menjelaskan pembuktian teorema bahwa jika suatu graf pembagi-nol mempunyai graf yang isomorfik dengan graf lengkap dengan lima simpul atau graf bipartite lengkap dengan masing-masing himpunan simpul sebanyak tiga simpul, maka graf pembagi-nol ini bersifat tak-planar. Karya ilmiah ini juga membuktikan beberapa graf pembagi-nol merupakan graf planar atau tak-planar.
Keyword: ring, graf pembagi-nol, graf planar