• Asian-Australasian Journal of Animal Sciences
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• v.2 no.3
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• pp.487-488
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• 1989

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.3
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• pp.243-246
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• 1990

Sixteen mature sheep were fed chaffed orchardgrass hay once a day for 7 days. In 7th day, four sheep were slaughtered either prior to eating, 2, 8 or 16 hours after the commencement of eating to measure digesta pool size and particle size distribution in the reticulo-rumen. One sheep slaughtered at 8 hours after feeding had absesses at the cardia and in the lungs and could not ruminate normally. Time spent eating and rumination in the sheep on the day before slaughtering were 85 and 29 (pseudo-rumination 227) minutes a day, compared to those were 112 and 277 minutes in the other animals, respectively. Total actual chewing time in the sheep with absesses and the other animals were 98 and $373{\pm}132$ minutes, respectively. Dry matter(DM) intake in the sheep was $2.9g/kgBW^{0.75}$ which was only about 17% of that in the other animals. The pool sizes of reticulo-rumen DM and neutral detergent fiber (NDF) were somewhat smaller in the sheep than the others. The pool sizes of large particle (>1.18mm) DM and NDF in the animal were similar with those in the other animals. Mean DM retention time in the sheep was 207.4 hours which was about 4.2 times longer than that in the other animals.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.3
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• pp.225-229
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• 1990

Sixteen mature sheep were fed chaffed orchardgrass hay once a day. Jaw movement of the sheep was recorded for 24 hours before slaughter. Four sheep were slaughtered either prior to eating, 2, 8 or 16 hours after the commencement of eating to measure digesta pool size and particle size distribution in the reticulo-rumen. Eating time was restricted to 120 minutes. Rumination time and actual chewing time during rumination increased with time after the meal. Mean dry matter (DM) pool size before and 2 hours after the meal were 1.36 and 2.45 times of DM intake, respectively. The proportion of large particle (>1.18 mm; LP) in the DM ingested during the meal was caculated to be about 70%. The mean DM and LP pool sizes per DM intake and the mean proportion of LP in the DM pool decreased with time after the meal. There were close negative relationships between either DM or LP pool sizes per DM intake and the chewing activities either expressed as time spent rumination, actual chewing time during rumination or total actual chewing time(total of eating time and actual chewing time during rumination). The difference between DM intake and LP pool size were assumed to be LP degradation in the present experiment, and correlated positively with the chewing activities. A large proportion of the digesta load was comprised of small particles, in excess of the daily intake.

• Asian-Australasian Journal of Animal Sciences
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• v.4 no.1
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• pp.99-102
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• 1991

To determine effect of time after feeding on distribution of digesta in the gastro-intestinal tracts of sheep given orchardgrass hay once a day, a total of fifteen ewes (mean live weight $51{\pm}12kg$) were slaughtered at 2, 8, 16 and 24 hours after feeding. Contents in the reticulo-rumen, omasum, abomasums, small intestine, cecum, and colon and rectum were totally collected and weighed. Weights of digesta in the reticulo-rumen were about 6 kg which contributed about 75% of the total in the whole tracts. Digesta on dry-matter basis totaled about 1 kg. The dry-matter concentration of digesta in the whole digestive tract was about 107 h/kg of fresh digesta. Distribution of moisture in the digestive tract changed in parallel with that of fresh digesta. There was no significant correlation observed between time after feeding and weights of digesta in the gastro-intestinal tracts. While, feed intake significantly correlated with digesta in the reticulo-rumen, cecum and whole tracts (p<0.01). Thus, time after feeding was inferred to have no influence upon the content of digesta in the digestive tract, but feed intake influenced on the content of digesta in the digestive tract at a low level of feeding.

• Journal of Veterinary Science
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• v.24 no.2
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• pp.27.1-27.15
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• 2023

Background: The relationships between the postpartum subacute ruminal acidosis (SARA) occurrence and predicted bacterial functions during the periparturient period are still not clear in Holstein cows. Objectives: The present study was performed to investigate the alterations of rumen fermentation, bacterial community structure, and predicted bacterial functional pathways in Holstein cows. Methods: Holstein cows were divided into the SARA (n = 6) or non-SARA (n = 4) groups, depending on whether they developed SARA during the first 2 weeks after parturition. Reticulo-ruminal pH was measured continuously during the study period. Reticulo-ruminal fluid samples were collected 3 weeks prepartum, and 2 and 6 weeks postpartum, and blood samples were collected 3 weeks before, 0, 2, 4 and 6 weeks postpartum. Results: The postpartum decline in 7-day mean reticulo-ruminal pH was more severe and longer-lasting in the SARA group compared with the non-SARA group. Changes in predicted functional pathways were identified in the SARA group. A significant upregulation of pathway "PWY-6383" associated with Mycobacteriaceae species was identified at 3 weeks after parturition in the SARA group. Significantly identified pathways involved in denitrification (DENITRIFICATION-PWY and PWY-7084), detoxification of reactive oxygen and nitrogen species (PWY1G-0), and starch degradation (PWY-622) in the SARA group were downregulated. Conclusions: The postpartum SARA occurrence is likely related to the predicted functions of rumen bacterial community rather than the alterations of rumen fermentation or fluid bacterial community structure. Therefore, our result suggests the underlying mechanisms, namely functional adaptation of bacterial community, causing postpartum SARA in Holstein cows during the periparturient period.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.1
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• pp.55-61
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• 1992

To determine the effect of time after feeding on distribution of particle size of digesta in the gastrointestinal tract, 16 sheep given orchardgrass first cut hay were slaughtered at 2, 8, 16 and 24 hours after feeding and digesta in diverse sites of the tract were sieved into four fractions of particle size larger than $1180{\mu}m$, 300-1180, 45-300 and less than 45. Following results were obtained: 1) In the reticulo-rumen, the proportion of particles larger than $1180{\mu}m$ decreased with the time after feeding, while the other particle size fractions did not change with time after feeding. 2) In the post-ruminal alimentary tract, the proportion of particles larger than $1180{\mu}m$ was significantly smaller than that in the reticulo-rumen and distribution of fractions of every particle size stayed consistently at about the same level irrespective of the time after feeding. 3) In the cecum, the fraction of particle size less than $45{\mu}m$ appeared to be selectively retained when the passage rate was considered.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.2
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• pp.306-314
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• 2003

Bio-hydrogenation of $C_{18}$-unsaturated fatty acids released from the hydrolysis of dietary lipids in the rumen, in general, occurs rapidly but the range of hydrogenation is quite large, depending on the degree of unsaturation of fatty acids, the configuration of unsaturated fatty acids, microbial type and the experimental condition. Conjugated linoleic acid (CLA) is incompletely hydrogenated products by rumen microorganisms in ruminant animals. It has been shown to have numerous potential benefits for human health and the richest dietary sources of CLA are bovine milk and milk products. The cis-9, trans-11 is the predominant CLA isomer in bovine products and other isomers can be formed with double bonds in positions 8/10, 10/12, or 11/13. The term CLA refers to this whole group of 18 carbon conjugated fatty acids. Alpha-linolenic acid goes through a similar bio-hydrogenation process producing trans-11 $C_{18:1}$ and $C_{18:0}$, but may not appear to produce CLA as an intermediate. Although the CLA has been mostly derived from the dietary $C_{18:2}$ alternative pathway may be existed due to the extreme microbial diversity in the reticulo-rumen. Regardless of the origin of CLA, manipulation of the bio-hydrogenation process remains the key to increasing CLA in milk and beef by dietary means, by increasing rumen production of CLA. Although the effect of oil supplementation on changes in fatty acid composition in milk seems to be clear its effect on beef is still controversial. Thus further studies are required to enrich the CLA in beef under various dietary and feeding conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.2
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• pp.91-97
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• 1989

The present experiment was carried out to investigate the effects of heat exposure on water metabolism and the passage of indigestible particles in sheep. Water intake, respiratory rate, rectal temperature and pH of ruminal fluid and urine were significantly higher (P<0.05) in the hot environment ($32\;^{\circ}C$) than in the control environment ($20\;^{\circ}C$). Urine osmolality and blood volume were increased, while glomerular filtration rate was decreased, in the hot environment. The liquid flow rate from reticulo-rumen and the excretion of indigestible particles of specific gravity 0.99 (but not 1.27 or 1.38) were increased in the hot environment. From these findings, it is suggested that an increased water intake evoked by heat exposure might affect the flow rate of digesta in sheep.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.12
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• pp.1708-1716
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• 2000

A study was made of diurnal changes in the ruminal bacteria associated with feed particles, i.e., non-associated (NAB), loosely associated (LAB), and tightly associated with particles (TAB), and the TAB concentration in different particle sizes from sheep fed orchardgrass (OG) or alfalfa (ALF) hay. Diaminopimelic acid (DAPA) was used to determine the TAB mass. Results showed that the bacterial masses in NAB and LAB were small, but comprised over 90% in TAB. The TAB mass in the ALF group sharply increased within 2 h after feeding and decreased afterward. The TAB mass showed the same trend in the OG group, increasing from 0 h to 2 h, but remained at the same level up to 14 h after feeding. The peak bacterial mass was, however, lower in the OG than the ALF group. The TAB concentration reflected the changes in total particulate tightly associated bacterial masses in both groups of hay fed sheep. Number of bacterial colonies per particle increased as the particulate size decreased in both groups. This difference, however, tended to decline as the postprandial period was prolonged. DAPA, however, tended to overestimate the TAB mass in the reticulo-rumen digesta of the hay fed sheep.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.1
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• pp.53-59
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• 1990

A study was conducted to investigate the release pattern of zinc form the zinc containing boluses and to see whether the released zinc can cure a zinc deficiency in sheep. Three sheep were used in this experiment and were fed a low zinc semi-synthetic diet throughout the experimental period. Each sheep was given a single pre-weighed zinc containing bolus when blood variables showed continuous zinc deficiency. The zinc containing boluses when placed within the reticulo-rumen of zinc deficient sheep, release zinc at the rate of 106.6 mg zinc/day for 39 days. At the end of depletion period there was a reduced feed consumption, plasma zinc concentration, plasma alkaline phosphatase activity and increased plasma zinc binding capacity which were 409 g, 0.18 mg/l, 87 U/l and 88.7% respectively and 521 g, 0.18 mg/l, 142 U/l, and 89.5% respectively before first and second blousing. After the administration of the first and second boluses, the feed consumption, plasma zinc levels and plasma alkaline phosphatase activities rose rapidly and far exceeded the starting values. The zinc binding capacity was reduced to 21.9% due to the administration of the first and second boluses. It is concluded that zinc boluses can be used for curing a zinc deficiency in sheep.