Diurnal Variation in Ruminal pH on the Digestibility of Highly Digestible Perennial Ryegrass During Continuous Culture Fermentation

Wales, William J.; Kolver, E.S.; Thorne, PM; Egan, A. R.

doi:10.3168/jds.s0022-0302(04)73344-5

Cited by 71 publications

(56 citation statements)

References 22 publications

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“…Ruminal pH ranged from 6.51 to 6.73 and was optimum for cellulolytic bacteria growth and feed fibre degradation (Wales, Kolver, Thorne, & Egan, ). The higher ruminal total VFA concentration and acetate molar proportion indicated that cellulolytic bacteria growth and enzyme activity were stimulated with increasing dietary CP level or RPFA supplementation, as observed in the previous studies (Wang et al, ,).…”

Section: Discussionmentioning

confidence: 99%

Effects of rumen‐protected folic acid and dietary protein level on growth performance, ruminal fermentation, nutrient digestibility and hepatic gene expression of dairy calves

Wang

et al. 2019

Animal Physiology Nutrition

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This study evaluated the effects of rumen‐protected folic acid (RPFA) supplementation and dietary protein level on growth performance, ruminal fermentation, nutrient digestibility and hepatic gene expression in calves. Forty Holstein male calves (161 ± 5.7 days of age and 192 ± 5.4 kg of body weight) were assigned to one of four groups in a randomized experimental design with a 2 × 2 factorial arrangement. Moderate crude protein (130.1 g CP/kg [MCP] or high crude protein (150.2 g CP/kg [HCP]) diets were fed without (RPFA−) or with 3.6 mg FA (RPFA+) as RPFA per kg dietary dry matter (DM). Calves were fed a total mixed ration with a corn silage to concentrate ratio of 50:50 on a DM basis. The CP×RPFA interaction was not significant for any of the studied variables. The unchanged DM intake, higher average daily gain and lower feed conversion ratio were observed for HCP or RPFA+. Ruminal pH was lower, and total volatile fatty acids (VFA) concentration was higher for HCP or RPFA+. Acetate proportion was higher, and propionate proportion was lower for HCP or RPFA+. As a result, the higher acetate to propionate ratio was observed. Ruminal ammonia N was higher for HCP, but was lower with RPFA supplementation. The higher digestibility of DM, OM, CP and NDF was observed. Blood glucose and insulin were unchanged, but albumin, total protein, GH and IGF‐1 were higher. Similarly, the higher hepatic expression of GH, IGF‐1, GHR, IGF‐1R, PI3K, mTOR and P70S6K was observed for HCP or RPFA+. The results indicated that increasing dietary CP content or supplementation with RPFA promoted growth performance of calves by improving nutrient utilization and up‐regulating hepatic expression of gene related to protein synthesis.

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Section: Discussionmentioning

confidence: 99%

Effects of rumen‐protected folic acid and dietary protein level on growth performance, ruminal fermentation, nutrient digestibility and hepatic gene expression of dairy calves

Wang

et al. 2019

Animal Physiology Nutrition

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“…This does not appear to be a plausible explanation for the results in this study since lambs maintained an adequate provision of fibre even ingesting ryegrass only. On the other hand, ingestion of high quality forages, such as ryegrass, could generate ruminal pH values below those required to ensure optimal fibre digestion (Wales et al. , 2004).…”

Section: Discussionmentioning

confidence: 99%

Preferences of lambs offered Italian ryegrass (Lolium multiflorum L.) and barley (Hordeum vulgare L.) herbage as choices

Catanese

Distel

Arzadún

2009

Grass and Forage Science

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Partial preference for feeds in ruminants is a welldocumented phenomenon although their explanation can be elusive. The hypothesis was tested that sheep offered herbage of two annual grass species differing in chemical composition free-choice would select a diet that would maximize the nutritive value of the diet compared with sheep offered each herbage separately through a greater nutrient balance and synchronization of nutrient release for efficient ruminal microbial function. Fifteen male lambs were placed into metabolic cages, and randomly assigned to three treatments (n = 5): Italian ryegrass fresh herbage (treatment R), barley fresh herbage (treatment B) or free-choice Italian ryegrass and barley fresh herbage (treatment RB). Both herbages had similar crude protein concentrations but Italian ryegrass herbage had higher concentration of water-soluble carbohydrates and lower concentration of fibre than barley herbage. Lambs were exposed to the treatments for 15 d. Lambs on treatment RB showed a partial preference of 0AE82 (s.e. 0AE031) for Italian ryegrass. Lambs on treatment RB had higher intakes of digestible dry matter and higher values for nitrogen retention than lambs on treatment B although similar to that of lambs on treatment R. The results for the dietary choices were not always consistent with maximizing the nutritive value of the diet. Other explanations, such as lambs needed to sample and track the nutritive value of dietary options or there was the development of transient food aversions, were also possible.

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“…Rumen pH was never above 6.15, regardless of treatment. In vitro studies by Wales et al (2004) demonstrated higher NDF and ADF digestibility when pH fluctuated around 6.1 compared with 5.6, but this difference was greatly reduced if pH was prevented from decreasing below 5.6. According to Calsamiglia et al (1999) and Mouriño et al (2001), reduced fibrolytic bacteria activity was observed below pH 5.8, but amylolytic bacteria are most active from 5.2 to 6 (Ishler et al, 1996).…”

Section: Rumen Phmentioning

confidence: 93%

The effect of buffering dairy cow diets with limestone, calcareous marine algae, or sodium bicarbonate on ruminal pH profiles, production responses, and rumen fermentation

Cruywagen

Taylor

Beya

et al. 2015

Journal of Dairy Science

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Six ruminally cannulated Holstein cows were used to evaluate the effect of 2 dietary buffers on rumen pH, milk production, milk composition, and rumen fermentation parameters. A high concentrate total mixed ration [35.2% forage dry matter (DM)], formulated to be potentially acidotic, was used to construct 3 dietary treatments in which calcareous marine algae (calcified remains of the seaweed Lithothamnium calcareum) was compared with limestone (control) and sodium bicarbonate plus limestone. One basal diet was formulated and the treatment diets contained either 0.4% of dietary DM as Acid Buf, a calcified marine algae product (AB treatment), or 0.8% of dietary DM as sodium bicarbonate and 0.37% as limestone (BC treatment), or 0.35% of dietary DM as limestone [control (CON) treatment]. Cows were randomly allocated to treatments according to a double 3×3 Latin square design, with 3 treatments and 3 periods. The total experimental period was 66 d during which each cow received each treatment for a period of 15 d before the data collection period of 7 d. Rumen fluid was collected to determine volatile fatty acids, lactic acid, and ammonia concentrations. Rumen pH was monitored every 10min for 2 consecutive days using a portable data logging system fitted with in-dwelling electrodes. Milk samples were analyzed for solid and mineral contents. The effect of treatment on acidity was clearly visible, especially from the period from midday to midnight when rumen pH dropped below 5.5 for a longer period of time (13 h) in the CON treatment than in the BC (8.7 h) and AB (4 h) treatments. Daily milk, 4% fat-corrected milk, and energy-corrected milk yields differed among treatments, with AB being the highest, followed by BC and CON. Both buffers increased milk fat content. Treatment had no effect on milk protein content, but protein yield was increased in the AB treatment. Total rumen volatile fatty acids and acetate concentrations were higher and propionate was lower in the AB treatment than in CON. The molar proportion of acetate was higher in AB than in CON, but that of propionate was lower in both buffer treatments than in CON. The acetate:propionate ratio was increased in the AB and BC treatments compared with CON. Lactic acid concentration was higher in the CON treatment than in the buffer treatments. Treatment had no effect on rumen ammonia concentrations. Results indicated that buffer inclusion in high concentrate diets for lactating dairy cows had a positive effect on milk production and milk composition. Calcareous marine algae, at a level of 90 g/cow per day, had a greater effect on rumen pH, milk production and milk composition, and efficiency of feed conversion into milk than sodium bicarbonate at a level of 180 g/cow per day.

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Diurnal Variation in Ruminal pH on the Digestibility of Highly Digestible Perennial Ryegrass During Continuous Culture Fermentation

Cited by 71 publications

References 22 publications

Effects of rumen‐protected folic acid and dietary protein level on growth performance, ruminal fermentation, nutrient digestibility and hepatic gene expression of dairy calves

Effects of rumen‐protected folic acid and dietary protein level on growth performance, ruminal fermentation, nutrient digestibility and hepatic gene expression of dairy calves

Preferences of lambs offered Italian ryegrass (Lolium multiflorum L.) and barley (Hordeum vulgare L.) herbage as choices

The effect of buffering dairy cow diets with limestone, calcareous marine algae, or sodium bicarbonate on ruminal pH profiles, production responses, and rumen fermentation

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