Nutrient metabolism in the rumen and milk production in cows fed on grass-silage and fresh grass based diets

Younge, Bridget; Murphy, John J.; Rath, M.

doi:10.1016/j.livprodsci.2003.11.003

Cited by 13 publications

(15 citation statements)

References 21 publications

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“…The apparent and true ruminal OM digestibility values for CS, FWCW, and UPWCW are within the ranges of 0.3 to 0.6 and of 0.4 to 0.7 of OM intake, respectively, as reviewed by Titgemeyer (1997). Although the values for GS exceed these ranges, they are similar to those reported by O'Mara et al (1998), Ahvenjärvi et al (2002), and Younge et al (2004) for diets consisting of GS supplemented with concentrates. The decreased flow of OM for GS was due to its increased ruminal OM digestibility and is probably related to its longer residence time and the low intake of GS, because decreased DMI can cause an increase in ruminal OM digestion (Robinson et al, 1985).…”

Section: Nutrient Flows and Digestionsupporting

confidence: 84%

Rumen fermentation, microbial protein synthesis, and nutrient flow to the omasum in cattle offered corn silage, grass silage, or whole-crop wheat1

Owens

McGee

Boland

et al. 2009

Journal of Animal Science

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The objectives of this study were to determine the relative effect of feeding corn silage (CS), fermented whole-crop wheat (FWCW), and urea-treated processed whole-crop wheat (UPWCW) compared with grass silage (GS), each supplemented with concentrates, on forage intake, ruminal fermentation, microbial protein synthesis, some plasma metabolites, and ruminal and total tract digestibility in cattle. Four ruminally fistulated steers with a mean BW of 509 kg (SD 6.3) were used in a 4 x 4 Latin square-designed experiment with each period lasting 21 d. The omasal sampling technique in combination with a triple marker method was used to measure nutrient flows to the omasum with Co-EDTA, Yb acetate, and indigestible NDF as liquid, small particle, and large particle phase markers, respectively. Microbial N flow was assessed from purine base concentrations. Steers fed CS, FWCW, and UPWCW consumed 2.7, 2.4, and 2.6 kg/d more (P < 0.05) forage and total DMI, respectively, than those fed GS-based diets. Rumen pH (P = 0.07) and lactic acid (P = 0.11) concentration did not differ between the forages. Rumen concentration of NH(3)-N was greatest for UPWCW and least for CS (P < 0.001). Total VFA concentrations were greater (P < 0.05) for CS than GS and UPWCW, with FWCW being intermediate. Acetate-to-propionate ratio (P < 0.05) was greater (P < 0.05) for UPWCW than the other forages, which did not differ. Apparent ruminal digestion of OM (P < 0.05) was less for CS, FWCW, and UPWCW than GS. Ruminal NDF digestibility was greater (P < 0.01) for GS than the other forages, which did not differ (P > or = 0.06). Total tract NDF digestibility was less (P < 0.05) for UPWCW than the other forages, with GS being greatest and CS and FWCW being intermediate. Starch intake was less (P < 0.001) for GS than the other forages, but there was no effect of forage on omasal starch flow (P = 0.23) or ruminal digestibility (P = 0.88). Flow of non-NH(3)-N and microbial N was greater (P < 0.05) for CS, FWCW, and UPWCW than GS. Efficiency of microbial N synthesis was greater (P < 0.05) for FWCW than GS and CS, with UPWCW being intermediate. Plasma beta-hydroxybutyrate concentrations were greatest with CS and least for GS (P < 0.001), whereas concentrations of plasma urea were least for CS and greatest for UPWCW (P < 0.001). In conclusion, feeding alternative forages to GS can significantly increase feed DMI and alter rumen fermentation and site of nutrient digestion when offered to cattle supplemented with 3 kg of concentrate daily.

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Section: Nutrient Flows and Digestionsupporting

confidence: 84%

Rumen fermentation, microbial protein synthesis, and nutrient flow to the omasum in cattle offered corn silage, grass silage, or whole-crop wheat1

Owens

McGee

Boland

et al. 2009

Journal of Animal Science

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“…Milk protein percentage was lower for GS, with no difference between G and ZG. Lower milk protein percentage has been reported previously for silage compared with grass-based diets (Keady et al, 1995;Younge et al, 2004) and this may be because of the lower flow of microbial nitrogen and total amino acid nitrogen for silage compared with grass-based diets (Younge et al, 2004). Milk lactose percentage was not different among the treatments.…”

Section: Dmi Milk Yield and Compositionmentioning

confidence: 47%

Grazing cows are more efficient than zero-grazed and grass silage-fed cows in milk rumenic acid production

Mohammed

Stanton

Kennelly

et al. 2009

Journal of Dairy Science

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Six rumen-cannulated Holstein cows in early lactation were assigned to 3 treatments: grazing (G), zero-grazing (ZG), and grass silage (GS) harvested from the same perennial rye grass sward in a 3 x 3 Latin square design with three 21-d periods. The objectives of this study were to investigate the underlying mechanisms for the reported elevation in milk rumenic acid (RA) concentration associated with G compared with ZG and GS, and to identify the important variables contributing to the milk RA response. Grazing animals were offered 20 kg of dry matter/cow per day; indoor animals were offered ad libitum grass or silage. A concentrate at a rate of 3 kg/d was also offered to all cows. Rumen, plasma, and milk samples were collected in the third week of each period. Data were analyzed by the MIXED procedure of SAS. Dry matter intakes were less for GS with no difference between G and ZG. Milk yield was greater for G than for ZG or GS. Milk fat and protein contents were less for GS with no difference between G and ZG. The combined intake (g/d) of linoleic and linolenic (18:3n-3) acids was different across the treatments (G: 433; ZG: 327; and GS: 164). Rumen pH was less for G with no difference between ZG and GS. Concentrations of volatile fatty acids and ammonia nitrogen in rumens were not different across the treatments. Wet rumen fill was less for G with no difference between ZG and GS. Vaccenic acid concentrations were different across the treatments in rumen (G: 12.30%, ZG: 9.31%, and GS: 4.21%); plasma (G: 2.18%, ZG: 1.47%, and GS: 0.66%) and milk (G: 4.73%, ZG: 3.49%, and GS: 0.99%). Milk RA concentrations were greater for G (2.07%) than for ZG (1.38%) and GS (0.54%). Milk desaturase index based on the ratio cis-9-14:1/14:0 was not different across the treatments. Milk RA yield per 100 g of linoleic acid and linolenic acid intake (efficiency) was 2.23, 1.50, and 0.62 g in G, ZG, and GS, respectively, suggesting that G cows were more efficient than ZG and GS cows in milk RA production. Stepwise regression analysis of a group of variables revealed that plasma vaccenic acid accounted for 95% of the variation in milk RA production. Milk desaturase index did not enter into the model. Overall findings suggest that substrate intake influenced milk RA production but it was not the only factor involved. There were differences in efficiency of milk RA production, which appears to depend on the factors regulating ruminal vaccenic acid production and its supply to the mammary tissue.

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“…A higher level of sulphur compounds was also detected in the EXT group. Dimethyl sulphide was the most involved molecule: it comes from methionine catabolism and has been positively correlated with grazing (Younge et al ., 2004; Coppa et al ., 2011). Finally, terpenes and esters were present in negligible amounts; for terpenes, it probably depended on the type of meadow and season (Tornambè et al ., 2006).…”

Section: Resultsmentioning

confidence: 99%

Volatile organic compounds in milk and mozzarella: Comparison between two different farming systems

Natrella

Gambacorta

Palo

et al. 2020

Int J of Food Sci Tech

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The volatile organic compounds (VOC) and sensory characteristics of milk and mozzarella from farms with different rearing systems were compared. Milk samples were taken from 9 intensive (INT) and 13 semi-extensive farms (EXT) in the grazing period. VOC were analysed by SPME-GC-MS, and sensory evaluation was carried out by paired comparison. The volatile profiles of milks were significantly different: acetone and isopropyl alcohol characterised INT milk, pentanoic and decanoic acids, hexanal, ethylacetate, toluene, dimethyl sulphide characterised milk from EXT farms. Also mozzarella was discriminated by VOC, but only a few compounds derived from milk. Based on sensory evaluation, milk from the two sources can be distinguished by odour and colour, mozzarella only by colour. It was hypothesised that heating during the stretching phase caused volatilisation of many milk volatile compounds and formation new aroma active molecules that overcame the 'primary odours' of milk.

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Nutrient metabolism in the rumen and milk production in cows fed on grass-silage and fresh grass based diets

Cited by 13 publications

References 21 publications

Rumen fermentation, microbial protein synthesis, and nutrient flow to the omasum in cattle offered corn silage, grass silage, or whole-crop wheat1

Rumen fermentation, microbial protein synthesis, and nutrient flow to the omasum in cattle offered corn silage, grass silage, or whole-crop wheat1

Grazing cows are more efficient than zero-grazed and grass silage-fed cows in milk rumenic acid production

Volatile organic compounds in milk and mozzarella: Comparison between two different farming systems

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