AbstractThe relationship between feed intake at production levels and enteric CH4 production in ruminants consuming forage-based diets is well described and considered to be strongly linear. Unlike temperate grazing systems, the intake of ruminants in rain-fed tropical systems is typically below maintenance requirements for part of the year (dry seasons). The relationship between CH4 production and feed intake in animals fed well below maintenance is unexplored, but changes in key digestive parameters in animals fed at low levels suggest that this relationship may be altered. We conducted a study using Boran yearling steers (n 12; live weight: 162·3 kg) in a 4 × 4 Latin square design to assess the effect of moderate to severe undernutrition on apparent digestibility, rumen turnover and enteric CH4 production of cattle consuming a tropical forage diet. We concluded that while production of CH4 decreased (1133·3–65·0 g CH4/d; P < 0·0001), over the range of feeding from about 1·0 to 0·4 maintenance energy requirement, both CH4 yield (29·0−31·2 g CH4/kg DM intake; P < 0·001) and CH4 conversion factor (Ym 9·1–10·1 MJ CH4/MJ gross energy intake; P < 0·01) increased as intake fell and postulate that this may be attributable to changes in nutrient partitioning. We suggest there is a case for revising emission factors of ruminants where there are seasonal nutritional deficits and both environmental and financial benefits for improved feeding of animals under nutritional stress.

Given their high nitrogen (N) concentration and low costs, sweet potato vine silage (SPVS) and urea-molasses blocks (UMB) are recommended supplements for tropical regions; therefore, they were investigated in this study. Six heifers were allocated to three diets: the roughage diet (R) consisted of wheat straw (0.61) and Rhodes grass hay (0.39; on dry matter (DM) basis); R + SPVS combined R (0.81) and SPVS (0.19); and with R + UMB animals had access to UMB. During two experimental periods, feed intake, feces and urine excretion, digesta passage, and rumen microbial protein synthesis were determined during seven days and methane emissions during three days. There was no treatment effect (p > 0.05) on DM and N intake. Apparent DM digestibility of R + SPVS (510 g/kg) was higher (p < 0.05) than of R (474 g/kg). Digesta passage and duodenal microbial N flow were similar for all diets (p > 0.05), while N retention was highest with R + SPVS (p > 0.05). Methane emissions per unit of digested feed (g CH4/kg dDM) were lower (p < 0.05) for R + SPVS (55.2) than for R (64.7). Hence, SPVS supplementation to poor–quality roughage has the potential to increase diet digestibility and N retention while reducing CH4 emissions.

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ABSTRAKPenelitian ini bertujuan untuk mengetahui karakteristik morfologis dan reproduksi kerbau pampangan di Propinsi Sumatera Selatan. Dilaksanakan di tiga kabupaten yaitu kabupaten OKI, Banyuasin dan Ogan Ilir selama 6 bulan. Metode yang digunakan adalah metode survei. Penarikan contoh bersifat multistage purposive sampling mulai dari penentuan kabupaten, kecamatan, serta peternak. Setelah ditetapkan tiga kabupaten lokasi sampel, akan dipilih masing-masing satu kecamatan sentra populasi yang jumlah populasinya terbanyak. Data yang dikumpulkan meliputi data primer dan data sekunder. Data yang diperoleh diolah secara matematis, disajikan secara tabulasi kemudian dijelaskan secara deskriptif, yaitu melukiskan secara sistematis fakta atau karakteristik morfologis dan reproduksi kerbau pampangan secara cermat dan faktual dari data yang telah terkumpulkan. Karakteristik morfologis kerbau pampangan adalah warna bulu hitam/hitam keabu-abuan, bentuk tubuh besar, temperamen tenang, kepala besar dan telinga panjang, tanduk ada yang tegak panjang dan melingkar ke arah belakang dan ada juga yang arah ke bawah. Bentuk ambing simetris dan berkembang dengan baik. Karakteristik reproduksi kerbau Pampangan umur pertama kawin rata-rata 2,3 tahun atau 27 bulan, umur beranak pertama 3,23 tahun, estrus (berahi) pertama setelah beranak 88,33 hari, kawin setelah beranak 139,11 hari, jarak beranak 14 bulan dan umur lepas sapih anak 9,07 bulan.Kata kunci: Karakteristik, morfologis, reproduksi, kerbau