Effects of Forage Particle Size and Grain Fermentability in Midlactation Cows. II. Ruminal pH and Chewing Activity

Chemical and physical treatments of barley grain increase ruminally resistant starch and can improve the rumen fermentation pattern. The objective of the present study was to evaluate the effects of chemical (addition of citric acid, CA) and physical (grinding to two different particle sizes, PS) treatment of barley grain on performance, rumen fermentation, microbial protein yield in the rumen and selected blood metabolites in growing calves. In all, 28 male Holstein calves (172 ± 5.1 kg initial BW) were used in a complete randomised design with a factorial arrangement of 2 barley grain particle sizes × 2 levels of citric acid. The diets were as follows: (i) small PS (average 1200 µm) barley grain soaked in water (no CA addition); (ii) small PS barley grain soaked in a CA solution (adding 20 g CA/kg barley); (iii) large PS (average 2400 µm) barley grain soaked in water (no citric acid addition) and (iv) large PS barley grain soaked in a citric acid solution (adding 20 g CA/kg barley). Barley grain was then incorporated at 35% in a total mixed ration and fed to the calves for 11 weeks. Feeding small PS barley decreased feed intake ( P = 0.02) and average daily weight gain ( P = 0.01). The addition of CA to barley grain did not affect intake but increased weight gain ( P < 0.01) and improved feed to gain ratio ( P = 0.03). Digestibility of organic matter and NDF tended ( P < 0.10) to increase, whereas faecal scoring was improved ( P = 0.03) and the presence of undigested grain particles in faeces was reduced ( P < 0.01) with CA-treated barley grain. Glucose and urea concentrations were increased (P < 0.01) in the blood of calves fed the CA-treated barley grain. Ruminal pH tended ( P = 0.08) to be decreased with more finely ground barley and was increased when barley grain was treated with CA. Total volatile fatty acid concentrations in the rumen did not differ among treatments ( P > 0.05). However, the molar proportion of propionate was increased ( P = 0.03) when barley was more finely ground, and that of acetate was increased ( P = 0.04) when CA was added to barley grain. The ruminal concentration of ammonia nitrogen was increased ( P < 0.01) and microbial nitrogen synthesis in the rumen tended to decrease by adding CA to barley. Treating barley grain with citric acid increased fibre digestibility of total mixed rations, attenuated the decrease in ruminal pH, and improved weight gain and feed efficiency in male Holstein growing calves fed a high-cereal diet (550 g cereal grain/kg diet).

Section: Discussioncontrasting

confidence: 41%

Influence of barley grain particle size and treatment with citric acid on digestibility, ruminal fermentation and microbial protein synthesis in Holstein calves

Kazemi-Bonchenari

Salem

López

2017

“…An increase in total saliva secretion may improve rumen buffering, preventing a decline in rumen pH and potentially reducing the risk of ruminal acidosis . Krause et al (2002) observed that pH decreased when geometric mean particle length (X gm ) of alfalfa silage decreased from 13.6 to 3.7 mm (fed at 39 : 61 forage to concentrate ratio, F : C).…”

Section: Introductionmentioning

confidence: 99%

Effect of forage particle length on rumen fermentation, sorting and chewing activity of late-lactation and non-lactating dairy cows

Suarez-Mena

Zanton

Heinrichs

2013

The objective of this study was to determine the effects of varying forage particle length on chewing activity, sorting behavior, rumen pH and rumen fill in late lactation and dry dairy cattle, fed rations with similar physically effective NDF but different mean particle length. Treatments consisted of three diets differing only in geometric mean length of forage: hay (5.40, 8.96 and 77.90 mm, for short (S), medium (M) and long (L) diets, respectively) for Experiment 1 (E1), and straw (10.16, 24.68 and 80.37 mm) for S, M and L diets, respectively, for Experiment 2 (E2). Hay or straw comprised the sole source of forage (50% and 75% of ration dry matter (DM) for E1 and E2, respectively). Both experiments used three rumen cannulated Holstein dairy cows, in late lactation for E1 and dry in E2, with 3 3 3 Latin square designs with 14 day periods. In E1, DM intake (DMI; 18.3 6 2.1 kg/day; mean 6 s.e.), pH (6.4 6 0.1), time spent eating (280 6 22.5 min/day), time spent ruminating (487 6 17 min/day), and total time spent chewing (767 6 34 min/day) were not different, whereas eating minutes per kilogram of DMI and NDF intake (NDFI) tended to increase linearly as forage length increased. Rumen digesta volume (l; 113.3 S, 117.8 M and 114.4 L 6 17.1) had a quadratic response, and rumen digesta weight tended to respond quadratically; however, differences were numerically small. In E2, DMI (8.3 6 1.3 kg/day), pH (6.7 6 0.1), time spent eating (236 6 23.5 min/day), time spent ruminating (468 6 45.2 min/day), total time spent chewing (704 6 67.7 min/day) and minutes per kilogram NDFI were not different, whereas minutes per kilogram of DMI had a trend for a quadratic effect. Rumen digesta volume (111 6 18.8 l) and weight (103 6 17.4 kg) were not different. In both experiments, cows sorted against longer particles as determined by a particle length selection index; this behavior increased linearly as particle length increased. Greater forage particle length increased sorting behavior, but had no effect on rumen fermentation or chewing behavior.

“…Despite the documented physiological importance of dietary PS, research has shown that the effects of forage PS are also dependent on the degradation characteristics of the diet (Krause et al, 2002a and2002b;Silveira et al, 2007). Several lines of evidence indicate that for the same forage PS in the diet, the physiological responses obtained are different when these diets are based on barley v. corn (Allen, 1997;Beauchemin and Rode, 1997;Lechartier and Peyraud, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Eating and ruminating activities were noted at 5-min intervals, and each activity was assumed to persist for the entire 5-min interval. A period of rumination was defined as at least 5 min of rumination occurring after at least 5 min without rumination (Krause et al, 2002b). A meal or period of eating was defined as at least one observation of eating activity occurring after at least 20 min without eating activity (Krause et al, 2002b).…”

mentioning

confidence: 99%

“…A period of rumination was defined as at least 5 min of rumination occurring after at least 5 min without rumination (Krause et al, 2002b). A meal or period of eating was defined as at least one observation of eating activity occurring after at least 20 min without eating activity (Krause et al, 2002b). Total time spent chewing was calculated as the total time spent eating and ruminating.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Grain source and marginal changes in forage particle size modulate digestive processes and nutrient intake of dairy cows

Nasrollahi

Khorvash

Ghorbani

et al. 2012

This study investigated the effects of, and interactions between, dietary grain source and marginal changes in alfalfa hay (AH) particle size (PS) on digestive processes of dairy cows. A total of eight Holstein dairy cows (175 days in milk) were allocated in a replicated 4 3 4 Latin square design with four 21-day periods. The experiment was a 2 3 2 factorial arrangement with two levels of theoretical PS of AH (fine 5 15 mm or long 5 30 mm) each combined with two different sources of cereal grains (barley grain alone or barley plus corn grain in a 50 : 50 ratio). Results showed that cows consuming diets supplemented with corn had greater dry matter and nutrient intakes (P , 0.01), independent of forage PS. In addition, the apparent digestibility of fiber fractions was greater for diets supplemented with corn (P 5 0.01). The feeding of barley grain-based diets was associated with greater apparent digestibility of non-fiber carbohydrates, and this variable was even greater when long AH was fed (P 5 0.04). Moreover, the feeding of long AH resulted in longer time spent eating (P 5 0.03) and higher pH (P , 0.01), as well as a tendency for higher acetate-to-propionate ratio in the rumen fluid (P 5 0.06) at 3 h post feeding. In conclusion, the results indicated that the marginal increase of PS of AH may prolong eating time and improve rumen fermentation, particularly in diets based on barley grain. Partial substitution of barley grain by corn can improve feed intake and fiber digestibility in mid-lactation dairy cows.Keywords: physically effective NDF, hay particle size, barley, corn ImplicationsThis study tested the hypothesis that grain fermentability and particle size (PS) of alfalfa hay have the potential to modify rumen conditions, digestion and performance of mid-lactation dairy cows. Indeed, the results showed an improved rumen environment and nutrient digestibility in cows fed a diet containing corn grain and long forage PS, respectively.