No abstract

A new animal calorimeter using a ventilated hood was constructed in Thailand. The recovery rates of our head cage were 96.5%, 97.0%, 95.7%, and 101.8%. The recovery rates of our head cage (95.7 101.8%) are reliable compared with Japanese whole-body chambers. The 99% CO 2 recovery time of our head cage was an average 14 min. It was shorter than whole-body chambers because of smaller effective volume and higher flow rate. Our head cage system excels at dynamic measurement of heat production. We started accumulating data concerning the energy value of Pangola grass (Digitaria eriantha) using 4 Brahman steers (body weight, 372.8 34.4 kg, mean standard deviation; age, 3 years old). They were fed Pangola grass for 21 days; the grass was harvested approximately 45 days after cutting in several farms around Bangkok. Digestible energy and metabolizable energy of Pangola grass hay in our study were 10.28 and 7.99 MJ/kg dry matter. The average volume of methane production was 228.3 L/day and energy loss in the form of methane was 0.097 of the gross energy intake. These values are acceptable when compared with those obtained when low-quality tropical feed is provided to the steers. Discipline: Animal industryAdditional key words: Brahman steers, digestible energy, metabolizable energy

We conducted a meta-data analysis to develop prediction equations to estimate enteric methane (CH ) emission from beef cattle in Southeast Asia. The dataset was obtained from 25 studies, which included 332 individual observations on nutrient intakes, digestibilities, and CH emissions. Cattle were provided tropical forage or rice straw, with or without concentrates in individual pens equipped with indirect open-circuit head hood apparatus. The simplest and best equation to predict daily CH emission was CH (g/day) = 22.71 (±1.008) × dry matter intake (DMI, kg/day) + 8.91 (±10.896) [R = 0.77; root mean square error (RMSE) = 19.363 g/day]. The best equation to predict CH energy as a proportion of gross energy intake (CH -E/GEI, J/100 J) was obtained using DMI per body weight (DMIBW, kg/100 kg), content (g/100 g DM) of ether extract (EE) and crude protein (CP), and DM digestibility (DMD, g/100 g); CH -E/GEI = -0.782 (±0.2526) DMIBW - 0.436 (±0.0548) EE - 0.073 (±0.0218) CP + 0.049 (±0.0097) DMD + 8.654 (±0.6517) (R = 0.39; RMSE = 1.3479 J/100 J GEI). It was indicated that CH emissions from beef cattle in Southeast Asia are predictable using present developed models including simple indices.

This study aimed to investigate the effects of pulsation rate of the milking machine on the proteinous components and gelatinase activity in the mammary secretion for optimal tissue remodeling during the dry period in tropical dairy cows. Nine healthy primiparous Thai crossbred Holstein cows (75%HF) were milked with various pulsation rates (50, 60, and 70 cycles/min) one week after calving. The total protein contents of the secretions increased along the time course in 50 and 60 cycles/min groups but not in 70 cycles/min group and were not different among the 3 groups along the time course. Lactoferrin and BSA abundance of the 3 groups as well as γ-globulin in 50 and 70 cycles/min groups also increased in a time-dependent manner, in which only γ-globulin abundance in 60 cycles/min group 14 days before drying off and lactoferrin in 50 cycles/min group 14 days after drying off were significantly higher than those of the other 2 groups. In tissue remodeling by gelatinase activity analysis, 50 cycles/ min group showed dramatic increases of Matrix metalloproteinase-9 (MMP-9) and MMP-2 activities after drying off, whereas 60 and 70 cycles/min groups had a significant but a smaller change (p<0.05) along the time course. Cows with 60 cycles/min exhibited dramatic increases of MMP-9 and MMP-2 activities than the other groups before drying off (p<0.05). The findings suggested that milking pulsation rate at 60 cycles/min resulted in higher activity of remodeling during mammary involution and thus may benefit the renewal and health of the udder in the long run.