The objective of this study was to determine whether feeding tannin-containing hays to heifers and mature beef cows influences enteric methane (CH4) emissions and nitrogen (N) excretion relative to feeding traditional legume and grass hays. Fifteen mature beef cows (Exp. 1) and 9 yearling heifers (Exp. 2) were each randomly assigned to treatment groups in an incomplete bock design with 2 periods and 6 types of hays with 3 hays fed each period (n = 5 cows and 3 heifers per treatment). Groups were fed tannin-containing [birdsfoot trefoil (BFT), sainfoin (SAN), small burnet (SML)], or non-tannin containing [alfalfa (ALF), cicer milkvetch (CMV), meadow bromegrass (MB)] hays. Each period consisted of 14 d of adjustment followed by 5 d of sample collection. Nine cows and 9 heifers were selected for the measurement of enteric CH4 emissions (sulfur hexafluoride tracer gas technique), and excretion of feces and urine, while dry matter intake (DMI) was measured for all animals. The concentration of condensed tannins in SAN and BFT was 2.5 ± 0.50% and 0.6 ± 0.09% of dry matter (DM), respectively, while SML contained hydrolyzable tannins (4.5 ± 0.55% of DM). Cows and heifers fed tannin-containing hays excreted less urinary urea N (g/d; P < 0.001) and showed lower concentrations of blood urea N (mg/dL; P < 0.001) than animals fed ALF or CMV, indicating that tannins led to a shift in route of N excretion from urine to feces. Additionally, cows fed either BFT or CMV showed the greatest percentage of retained N (P < 0.001). Enteric CH4 yield (g/kg of DMI) from heifers (P = 0.089) was greatest for MB, while daily CH4 production (g/d) from heifers (P = 0.054) was least for SML. However, digestibility of crude protein was reduced for cows (P < 0.001) and heifers (P < 0.001) consuming SML. The results suggest that tannin-containing hays have the potential to reduce urinary urea N excretion, increase N retention, and reduce enteric CH4 emissions from beef cattle. The non-bloating tannin-free legume CMV, may also reduce environmental impacts relative to ALF and MB hays by reducing N excretion in urine and increasing N retention.
1 April 2004 in Colloids and Surfaces B: Biointerfaces
Public concerns about water issues are key considerations in responding to changing hydrologic conditions. Literature is mixed on the social profiles associated with resource-related risks. Using data from a household survey, we compare concerns about water shortage, climate change impacts on water supply, poor water quality, and flooding. We assess the combined influence of social and locational factors on each concern and variations across three valleys in northern Utah. Generalized linear mixed modeling is used, given the ordinal nature of most variables. Water shortage was the greatest concern, and female, older, nonwhite, and recreationally active respondents were generally more concerned about water issues than their counterparts. Education, income, and religious identity presented more complicated relationships with water concerns, with significant interaction effects with valley geography. This study has implications for improving public involvement in risk management and engendering support for future water policy and planning strategies to address these risks.
This experiment was conducted to test a hypothesis that lactating dairy cows fed 35% brown midrib (BMR) corn silage and 25% alfalfa hay (dry matter (DM) basis) would consume more DM around peak lactation compared with those fed conventional corn silage (CS), resulting in longer peak milk production. Twenty-eight multiparous Holstein cows were used starting at the onset of lactation through 180 d in milk (DIM). Treatments were formulated to maintain a forage-to-concentrate ratio of 60:40, differing only in the CS hybrids used. Two dietary treatments were assessed in a completely randomized design: total mixed ration based on conventional CS (CCS) and total mixed ration based on BMR silage. Through peak lactation (1-60 DIM), DM intake was not different between dietary treatments, whereas DM intake post-peak lactation (61-180 DIM) tended to increase by feeding the BMR diet compared with the CCS diet (25.8 vs. 24.7 kg/d). Cows fed the BMR diet tended to lose less body weight through peak lactation compared with those fed the CCS diet (-0.22 vs. -0.52 kg/d). Although milk yield was not different between dietary treatments through peak lactation, milk yield post-peak lactation increased by feeding the BMR diet compared with the CCS diet (41.0 vs. 38.8 kg/d). Yield of 3.5% fat-corrected milk was similar between dietary treatments throughout the experiment (41.4 kg/d, on average), but milk fat concentration decreased by feeding the BMR diet compared with the CCS diet post-peak lactation (3.47 vs. 3.80%). Overall milk protein concentration was similar between dietary treatments throughout the experiment (2.96%, on average), whereas milk protein yield tended to be higher for the BMR diet post-peak lactation compared with the CCS diet (1.19 vs.1.13 kg/d). Feeding BMR silage with a high dietary concentration of alfalfa hay maintained more body weight, but did not affect milk production through peak lactation; however, cows fed the BMR diet post-peak lactation consumed more feed and maintained longer peak milk yield, leading to greater overall milk production and milk protein yield.