The effects of processed, urea-treated whole-crop wheat or maize silage and supplementation of whole-crop wheat on the performance of dairy cows

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The effect of rate of substitution of processed, urea-treated whole-crop wheat (pWCW) for grass silage on intake, performance and whole-tract digestibility was evaluated using 44 dairy cows. Cows received 10.5 kg of concentrates per day and one of the following forage mixtures (dry matter (DM) basis): grass silage alone (W-0); 0.75 grass silage, 0.25 pWCW (W-25); 0.5 grass silage, 0.5 pWCW (W-50) or 0.25 grass silage, 0.75 pWCW (W-75). Forage DM intake increased linearly with inclusion rate of pWCW from 9.7 kg DM per day in cows fed W-0 to 14.6 kg DM per day in W-75. By contrast, milk and protein yield (kg/day) were higher (P , 0.05) in cows receiving W-25 compared with W-0, but there was no effect (P . 0.05) of treatment on fat yield (kg/day). From week 11 of the experiment onwards, body condition score increased with rate of inclusion of pWCW ( P , 0.05). Whole-tract apparent digestibility of organic matter (OM) and fibre (kg/kg), decreased linearly with rate of inclusion of pWCW. Assuming a constant digestibility of starch in the other diet components, the apparent digestibility of starch in pWCW was 0.95 kg/kg and was not affected by rate of inclusion (P . 0.05). Four continuous culture vessels were used to determine the effect of rate of inclusion of pWCW on ruminal metabolism in four periods, each of 14 d duration with sampling conducted on days 9 to 14. Vessel ammonia concentration increased linearly ( P , 0.05) with rate of inclusion of pWCW whilst mean pH tended (P ¼ 0.06) to decrease. The ratio of acetate to propionate increased from 2.5 in vessels receiving W-0 to 3.2 in those receiving W-75 (P , 0.001). There was no effect (P . 0.05) of treatment on digestibility (g/g) of OM, fibre or starch or microbial protein flow (g/day). It is concluded that forage DM intake increased linearly with rate of inclusion of pWCW, but there was no further improvement in milk yield from inclusion rates above 0.25 of the forage DM, with body condition score increasing instead. Increasing the inclusion rate of pWCW resulted in a more ketogenic volatile fatty acid profile but did not affect the efficiency of microbial protein synthesis when determined in vitro.

Section: Discussionsupporting

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of rate of substitution of processed, urea-treated whole-crop wheat for grass silage on the intake, milk production and diet digestibility in dairy cows and ruminal metabolism in vitro

Sinclair

Bond

Huntington

et al. 2007

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“…In contrast, the maize silage had a lower than expected concentration of starch (221 g/kg DM) and increased CP concentration (105 g/kg DM) compared with target values (Sinclair et al, 2005). However, the maize silage utilized here had DM and ME concentrations of 317 g/kg and 11.2 MJ/kg DM, respectively, which were in line with target values.…”

Section: Feed Compositionsupporting

confidence: 57%

The influence of grass silage-to-maize silage ratio and concentrate composition on methane emissions, performance and milk composition of dairy cows

Hart

Huntington

Wilkinson

et al. 2015

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It is well-established that altering the proportion of starch and fibre in ruminant diets can alter ruminal and post-ruminal digestion, although quantitative evidence that this reduces enteric methane (CH 4 ) production in dairy cattle is lacking. The objective of this study was to examine the effect of varying grass-to-maize silage ratio (70 : 30 and 30 : 70 DM basis), offered ad libitum, with either a concentrate that was high in starch or fibre, on CH 4 production, intake, performance and milk composition of dairy cows. A total of 20 cows were allocated to one of the four experimental diets in a two-by-two factorial design run as a Latin square with each period lasting 28 days. Measurements were conducted during the final 7 days of each period. Cows offered the high maize silage ration had a higher dry matter intake (DMI), milk yield, milk energy output and lower CH 4 emissions when expressed per kg DMI and per unit of ingested gross energy, but there was no difference in total CH 4 production. Several of the milk long-chain fatty acids (FA) were affected by forage treatment with the most notable being an increase in 18:0, 18:1 c9, 18:2 c9 c12 and total mono unsaturated FA, observed in cows offered the higher inclusion of maize silage, and an increase in 18:3 c9 c12 c15 when offered the higher grass silage ration. Varying the composition of the concentrate had no effect on DMI or milk production; however, when the high-starch concentrate was fed, milk protein concentration and milk FAs, 10:0, 14:1, 15:0, 16:1, increased and 18:0 decreased. Interactions were observed for milk fat concentration, being lower in cows offered high-grass silage and high-fibre concentrates compared with the high-starch concentrate, and FA 17:0, which was the highest in milk from cows fed the high-grass silage diet supplemented with the high-starch concentrate. In conclusion, increasing the proportion of maize silage in the diets of dairy cows increased intake and performance, and reduced CH 4 production, but only when expressed on a DM or energy intake basis, whereas starch-to-fibre ratio in the concentrate had little effect on performance or CH 4 production.Keywords: methane, dairy cows, forage, SF 6 tracer ImplicationsMethane production by ruminants is becoming an increasing concern due to its contribution to greenhouse gas emissions. Dietary strategies to reduce methane production in terms of supplying dietary supplements can result in pollution swapping, and are therefore not desirable. Researchers examine the effect of changing the ratio of grass and maize silage in addition to changing the amount of starch and fibre in the concentrate. The results obtained are related to national greenhouse gas inventories and potential effects of cropping systems on greenhouse gas emissions along with animal performance. IntroductionGlobally, agriculture, forestry and land use change account for 56% of non CO 2 anthropogenic greenhouse gas emissions, with methane (CH 4 ) from enteric fermentation accounting for 36% of this (Smith et al., 2014...

“…The forages and straight feeds were mixed daily using a Keenan Compact forage mixer calibrated to 6 1 kg, and fed through electronic roughage intake feeders (Insentec B.V., Marknesse, the Netherlands) fitted with an automatic animal identification and forage weighing system calibrated to 6 0.1 kg (Sinclair et al, 2005). Fresh feed was offered daily at 0800 h at the rate of 1.05 of ad libitum intake, with refusals collected twice weekly on a Tuesday and Friday.…”

Section: Protected Urea and Milk Performancementioning

confidence: 99%

The partial replacement of soyabean meal and rapeseed meal with feed grade urea or a slow-release urea and its effect on the performance, metabolism and digestibility in dairy cows

Sinclair

Blake

Griffin

et al. 2012

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The objectives of the study were to determine the effect of the partial replacement of soyabean meal and rapeseed meal with feed grade urea or a slow-release urea on the performance, metabolism and whole-tract digestibility in mid-lactation dairy cows. Forty-two Holstein-Friesian dairy cows were allocated to one of three dietary treatments in each of three periods of 5 weeks duration in a Latin square design. Control (C) cows were offered a total mixed ration based on grass and maize silages and straight feeds that included 93 g/kg dry matter (DM) soyabean meal and 61 g/kg DM rapeseed meal. Cows that received either of the other two treatments were offered the same basal ration with the replacement of 28 g/kg DM soyabean and 19 g/kg DM rapeseed meal with either 5 g/kg DM feed grade urea (U) or 5.5 g/kg DM of the slow-release urea (S; Optigen R ; Alltech Inc., Kentucky, USA), with the content of maize silage increasing. There was no effect (P . 0.05) of dietary treatment on DM intake, which averaged 22.5 kg/day. Similarly, there was no effect (P . 0.05) of treatment on daily milk or milk fat yield but there was a trend (P 5 0.09) for cows offered either of the diets containing urea to have a higher milk fat content (average of 40.1 g/kg for U and S v. 38.9 g/kg for C). Milk true protein concentration and yield were not affected by treatment (P . 0.05). Milk yield from forage and N efficiency (g milk N output/g N intake) were highest (P , 0.01) in cows when offered S and lowest in C, with cows receiving U having intermediate values. Cows offered S also tended to have the highest live weight gain (0.38 kg/day) followed by U (0.23 kg/day) and C (0.01 kg/day; P 5 0.07). Plasma urea concentrations were higher (P , 0.05) at 2 and 4 h post feeding in cows when offered U and lowest in C, with animals receiving S having intermediate values. There was no effect (P . 0.05) of treatment on whole-tract digestibility. In conclusion, the partial replacement of soyabean meal and rapeseed meal with feed grade urea or a slow-release urea can be achieved without affecting milk performance or diet digestibility, with the efficiency of conversion of dietary N into milk being improved when the slow-release urea was fed.