Impact of feeding native Caatinga pasture on the rumen histomorphometry of sheep raised in semi-extensive management.

In the northeastern region of Brazil, sheep and goat farming, encompassing around 20 million animals, is predominantly a subsistence activity. Forage quality plays a crucial role in animal productivity, posing a complex interplay between plant and animal aspects. The Caatinga biome, vital for livestock in the region, serves as a significant source for animal diet through pastures. This study aimed to conduct a histomorphometric evaluation of sheep rumens in a semi-extensive system, comparing those feeding on native Caatinga pastures to those on cultivated pastures. Histological processing followed standard protocols, with morphometry focusing on six viable rumen papillae and the submucosa and muscular layer thickness. Statistical correlation analysis revealed morphological differences in papillae across various rumen regions. Morphometric data indicated no significant difference in papillae area between the groups, with average values in Group A surpassing those in Group B, except for width. This study establishes a morphological and morphometric pattern for rumen regions linked to diet types-native or cultivated. The findings not only enhance understanding of the dietary foundation in the Caatinga's extensive system, but also contribute valuable insights for formulating nutritional strategies to enhance sheep production in the region. This research sheds light on the intricacies of forage-based animal nutrition, particularly in semi-extensive systems, offering a foundation for future studies and practices to optimise livestock management in the northeastern Brazilian context.

Red seaweed (Asparagopsis taxiformis) supplementation reduces enteric methane by over 80 percent in beef steers.

The red macroalgae (seaweed) Asparagopsis spp. has shown to reduce ruminant enteric methane (CH4) production up to 99% in vitro. The objective of this study was to determine the effect of Asparagopsis taxiformis on CH4 production (g/day per animal), yield (g CH4/kg dry matter intake (DMI)), and intensity (g CH4/kg ADG); average daily gain (ADG; kg gain/day), feed conversion efficiency (FCE; kg ADG/kg DMI), and carcass and meat quality in growing beef steers. Twenty-one Angus-Hereford beef steers were randomly allocated to one of three treatment groups: 0% (Control), 0.25% (Low), and 0.5% (High) A. taxiformis inclusion based on organic matter intake. Steers were fed 3 diets: high, medium, and low forage total mixed ration (TMR) representing life-stage diets of growing beef steers. The Low and High treatments over 147 days reduced enteric CH4 yield 45 and 68%, respectively. However, there was an interaction between TMR type and the magnitude of CH4 yield reduction. Supplementing low forage TMR reduced CH4 yield 69.8% (P <0.01) for Low and 80% (P <0.01) for High treatments. Hydrogen (H2) yield (g H2/DMI) increased (P <0.01) 336 and 590% compared to Control for the Low and High treatments, respectively. Carbon dioxide (CO2) yield (g CO2/DMI) increased 13.7% between Control and High treatments (P = 0.03). No differences were found in ADG, carcass quality, strip loin proximate analysis and shear force, or consumer taste preferences. DMI tended to decrease 8% (P = 0.08) in the Low treatment and DMI decreased 14% (P <0.01) in the High treatment. Conversely, FCE tended to increase 7% in Low (P = 0.06) and increased 14% in High (P <0.01) treatment compared to Control. The persistent reduction of CH4 by A. taxiformis supplementation suggests that this is a viable feed additive to significantly decrease the carbon footprint of ruminant livestock and potentially increase production efficiency.

Effects of transport stress on pathological injury and expression of main heat shock proteins in the caprine stomach.

BACKGROUND: Transportation is necessary to introduce new breeds of goats to the farm and move the adult meat goat from the farm to the slaughterhouse. However, these actions may give rise to transport stress. Heat shock proteins (HSPs) are playing some important regulate roles during transport stress. The aim of this study was to evaluate the effects of transport stress on the pathological injury and HSPs expression in the stomach of goats. A total of three batches of Ganxi goats from western Jiangxi province were enrolled in this study. For each batch, twelve healthy adult male goats were randomly divided into three groups (four goats per batch and per group): Control group, stress group transported during 2 h and stress group transported during 6 h. RESULTS: Our results showed that the different degrees of stomach walls damage, with the change of expression levels of heat shock protein 27 (HSP27), heat shock protein 70 (HSP70) and heat shock protein 90 (HSP90), occurred after goats transportation. In rumen, the mRNA and protein expressions of HSP27 and HSP70 were increased after transport stress, but not HSP90. In reticulum, all three HSPs mRNA and protein levels were upregulated after 2 h transport, but decreased after 6 h transport. In omasum, HSP27 and HSP70 mRNA and protein were increased after transport stress, however, HSP90 mRNA level only had a slightly enhancement after transport stress. In abomasum, HSP70 and HSP90 mRNA and protein levels were increased after transport stress, but HSP27 was decreased after transport stress. CONCLUSIONS: Taken together, these results revealed that the pathological changes in the gastric tissues and the stomach HSPs expression in goats are related to transport stress and duration. Moreover, this study also provides some new data to advocate reducing transport stress of goats and improving animal welfare.

Effect of replacement of antibiotics with thyme and celery seed mixture on the feed intake and digestion, ruminal fermentation, blood chemistry, and milk lactation of lactating Barki ewes.

The study investigated the effect of in-feed administration of dried thyme leaf and celery seed mixture (at 1 : 1 DM basis) compared with salinomycin ionophore on milk production and milk nutritive value of Barki ewes. Thirty ewes (37.5 ± 1.8 kg), divided into 3 treatment groups, were fed: (1) a complete control diet comprising concentrates and fodder maize (Zea mays L.) at 60 : 40 dry matter basis, (2) the control diet plus 20 g of thyme and celery mixture supplementation and (3) the control diet supplemented with 1 g of salinomycin per ewe daily for 90 days. Inclusion of thyme-celery treatment increased (P < 0.05) weight gain, average daily gain, milk yield, milk component yields, and feed efficiency, without affecting milk composition. In addition, the thyme-celery treatment enhanced (P < 0.05) nutrient intake and digestibility, total ruminal volatile fatty acids, branched chain fatty acids, and acetate proportions and decreased ammonia-N concentration. Thyme-celery treatment increased (P < 0.05) serum glucose, thyroxine, and glutamate-pyruvate transaminase concentrations. It is concluded that the thyme and celery mixture (1 : 1 DM basis) at 20 g per lactating ewe daily can replace the salinomycin ionophore. Enhanced feed utilization and lactational performance as well as milk nutritive value for human consumption were observed with the natural additive mixture supplementation.

Relationship between true digestibility of dietary phosphorus and gastrointestinal bacteria of goats.

The present research was conducted to evaluate the connection between the true digestibility of Phosphorus (TDP) in diet and bacterial community structure in the gastrointestinal tract (GIT) of goats. Twenty-eight Nubian goats were chosen and metabolic experiment was conducted to analyze TDP of research animals. Eight goats were grouped into the high digestibility of phosphorus (HP) phenotype, and another 8 were grouped into the low digestibility of phosphorus (LP) phenotype. And from the rumen, abomasum, jejunim, cecum and colon content of the goats, bacterial 16S rRNA gene amplicons were sequenced. In the rumen 239 genera belonging to 23 phyla, in abomasum 319 genera belonging to 30 phyla, in jejunum 248 genera belonging to 36 phyla, in colon 248 genera belonging to 25 phyla and in cecum 246 genera belonging to 23 phyla were noticed. In addition, there was a significant correlation between the TDP and the abundance of Ruminococcaceae_UCG-010, Ruminococcus_2, Ruminococcaceae_UCG-014, Selenomonas_1 and Prevotella in the rumen, Lachnospiraceae_ND3007_group, Saccharofermentans, Ruminococcus_1, Ruminococcaceae_UCG-014, Lachnospiraceae_XPB1014_group and Desulfovibrio in the abomasum, Prevotella, Clostridium_sensu_stricto_1, Fibrobacter, Desulfovibrio and Ruminococcus_2 in the jejunum, Ruminococcaceae_UCG-014 in the colon, and Desulfovibrio in the cecum. Present research trial recommended that the community of gastrointestinal microbiota is a factor affecting TDP in goats.

Causes of death of beef cattle raised in feedlots / Causas de morte de bovinos de corte criados em confinamentos

The causes of death of cattle kept in pre-export feedlots (PEFs) and in feedlot for finishing for slaughter are described. Two studies were conducted: a retrospective study of mortality cases in feedlots from 2000 to 2017 registered at the "Laboratório Regional de Diagnóstico" of the "Faculdade de Veterinária" of the "Universidade Federal de Pelotas"; and a prospective study from January 2018 to August 2019, following up 22 feedlots for finishing and six PEFs for the export of live cattle. From January 2000 to August 2019 samples of 150 cases of diseases that affected feedlot cattle were received from 22 feedlots for finishing and 115 of the six PEFs followed. Mortality considering all diagnosed diseases was significantly higher in feedlots for finishing (p<0.05), than in PEFs for the export of live cattle, of 1% and 0.12%, respectively. Diseases of the digestive system were the most important causes, of death in feedlots regardless of its purpose. Acidosis presented the highest mortality rates both in feedlot for finishing (3.33%) as in PEFs for export (0.95%). In all cases the disease occurred due to failure in the adaptation of animals to the ingestion of concentrated foods. Bovine tick fever and pneumonia presented mortality rates of 0.13% and 0.09%, respectively in PEFs. In the feedlot for finishing seneciosis was the second cause of death due to cattle coming from areas with high infestation by the plant. In the present study, it was possible to identify the main diseases that occur in cattle feedlots for finishing or for the export of live animals in the southern region of Rio Grande do Sul. These diseases are known in other systems of cattle breeding and can be prevented or controlled through management, chemoprophylaxis or vaccination, minimizing losses due to mortality.(AU)

Descrevem-se as causas de morte de bovinos mantidos confinados em estabelecimentos pré-embarque (EPEs) para exportação de animais vivos e em estabelecimentos de terminação para abate. Foram realizados dois estudos: um retrospectivo dos casos de mortalidade em confinamentos de 2000 a 2017 registrados no Laboratório Regional de Diagnóstico da Faculdade de Veterinária da Universidade Federal de Pelotas; e um estudo prospectivo de janeiro de 2018 a agosto de 2019, acompanhando-se 22 confinamentos de terminação e seis EPEs para exportação de bovinos vivos. No total, de janeiro de 2000 a agosto de 2019 foram recebidos no LRD-UFPel amostras de 150 casos de enfermidades que afetaram bovinos confinados, 35 provenientes de 22 confinamentos de terminação e 115 dos seis EPEs acompanhados. A mortalidade considerando-se todas as enfermidades diagnosticadas foi significativamente maior nos confinamentos para terminação (p<0,05), do que nos EPEs para exportação de bovinos vivos, de 1% e 0,12%, respectivamente. As doenças do sistema digestivo foram as causas de morte mais importante nos confinamentos, independente da finalidade. Acidose apresentou as maiores taxas de mortalidade tanto nos confinamentos para terminação (3,33%) como nos EPEs para exportação (0,95%). Em todos os casos a doença ocorreu devido a falha na adaptação dos animais à ingestão de alimentos concentrados. Tristeza parasitária bovina e pneumonias apresentaram taxas de mortalidade de 0,13% e 0,09, respectivamente em EPEs de exportação. Nos confinamentos para terminação a seneciose foi a segunda causa de morte devido aos bovinos serem provenientes de áreas com alta infestação pela planta. Este estudo permitiu identificar as principais enfermidades diagnosticadas em confinamentos para terminação de bovinos ou para exportação de bovinos vivos na região Sul do Rio Grande do Sul. Observou-se que são doenças que ocorrem em outros sistemas de criação de bovinos e que podem ser prevenidas ou controladas por meio de manejo, quimioprofilaxia ou vacinação, minimizando prejuízos por mortalidade de animais.(AU)

Histamine receptors mediate contraction of reticular groove smooth muscle of adult goats.

The present study was conducted to evaluate the effect of histamine and to characterise its receptor subtypes in reticular groove (RG) smooth muscle of adult goats. The studies were done using floor and lip regions of RG. We used tension experiments on smooth muscle of RG isolated from adult goat for functional characterisation of H1 and H2 receptors. Western blotting and immunohistochemistry experiments were conducted for molecular characterisation of these receptors. Histamine evoked concentration-dependent contraction of isolated RG circular and longitudinal smooth muscle preparation. Pyrilamine antagonised the action of histamine. Histamine did not induce any relaxant effect on RG preparations. Additionally, cimetidine did not produce any significant effect on histamine-induced response. Non-selective histaminic receptor antagonist cyproheptadine attenuated the contraction response to histamine in the smooth muscle. Molecular characterisation and localisation of H1 and H2 receptor proteins confirmed the presence of these receptors in RG. It is most likely that histamine-induced contractile effect in RG smooth muscle of goats is mediated by H1 histaminic receptors.

A metagenomics investigation of carbohydrate-active enzymes along the goat and camel intestinal tract

Studies of the digestive microbiota of ruminant animals most often focus on the bacterial diversity in the rumen or the feces of the animals, but little is known about the diversity and functions of their distal intestine. Here, the bacterial microbiota of the distal intestinal tract of two goats and two camels was investigated by metagenomics techniques. The bacterial taxonomic diversity and carbohydrate-active enzyme profile were estimated for samples taken from the small intestine, the large intestine, and the rectum of each animal. The bacterial diversity and abundance in the small intestine were lower than in the rectal and large intestinal samples. Analysis of the carbohydrate-active enzyme profiles at each site revealed a comparatively low abundance of enzymes targeting xylan and cellulose in all animals examined, similar to what has been reported earlier for sheep and therefore suggesting that plant cell wall digestion probably takes place elsewhere, such as in the rumen

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Amphistomes.

Amphistomes, commonly referred to as 'stomach' or 'rumen' flukes because of the localization of these flukes in the stomach of ruminants, are digenetic trematodes distinguished by the absence of an oral sucker and the position of the ventral sucker or acetabulum at the posterior end of the body. The body is characterized by leaf-like fleshy structure, pink or red in colour with a large posterior sucker. Amphistomes are an important group of parasites since they cause 'amphistomiasis' (variously known as paramphistomosis/amphistomosis), a serious disease of great economic importance in ruminants worldwide. These parasites have a broad spectrum of definitive hosts together with a wide geographical distribution. Though, they form a continuous evolutional lineage from fishes to mammals, amphistomes mainly inhabit the rumen and reticulum of ruminant mammals, while some species occur in the large intestine or parenteric sites of ruminants, pigs, equines and man.

Enteric methane emission from Jersey cows during the spring transition from indoor feeding to grazing.

Organic dairy cows in Denmark are often kept indoors during the winter and outside at least part time in the summer. Consequently, their diet changes by the season. We hypothesized that grazing might affect enteric CH4 emissions due to changes in the nutrition, maintenance, and activity of the cows, and they might differentially respond to these factors. This study assessed the repeatability of enteric CH4 emission measurements for Jersey cattle in a commercial organic dairy herd in Denmark. It also evaluated the effects of a gradual transition from indoor winter feeding to outdoor spring grazing. Further, it assessed the individual-level correlations between measurements during the consecutive feeding periods (phenotype × environment, P × E) as neither pedigrees nor genotypes were available to estimate a genotype by environment effect. Ninety-six mixed-parity lactating Jersey cows were monitored for 30 d before grazing and for 24 d while grazing. The cows spent 8 to 11 h grazing each day and had free access to an in-barn automatic milking system (AMS). For each visit to the AMS, milk yield was recorded and logged along with date and time. Monitoring equipment installed in the AMS feed bins continuously measured enteric CH4 and CO2 concentrations (ppm) using a noninvasive "sniffer" method. Raw enteric CH4 and CO2 concentrations and their ratio (CH4:CO2) were derived from average concentrations measured during milking and per day for each cow. We used mixed models equations to estimate variance components and adjust for the fixed and random effects influencing the analyzed gas concentrations. Univariate models were used to precorrect the gas measurements for diurnal variation and to estimate the direct effect of grazing on the analyzed concentrations. A bivariate model was used to assess the correlation between the 2 periods (in-barn vs. grazing) for each gas concentration. Grazing had a weak P × E interaction for daily average CH4 and CO2 gas concentrations. Bivariate repeatability estimates for average CH4 and CO2 concentrations and CH4:CO2 were 0.77 to 0.78, 0.73 to 0.80, and 0.26, respectively. Repeatability for CH4:CO2 was low (0.26) but indicated some between-animal variation. In conclusion, grazing does not create significant shifts compared with indoor feeding in how animals rank for average CH4 and CO2 concentrations and CH4:CO2. We found no evidence that separate evaluation is needed to quantify enteric CH4 and CO2 emissions from Jersey cows during in-barn and grazing periods.

Microbial diversity in the rumen, reticulum, omasum, and abomasum of yak on a rapid fattening regime in an agro-pastoral transition zone.

The ruminant digestive system harbors a complex gut microbiome, which is poorly understood in the case of the four stomach compartments of yak. High-throughput sequencing and quantitative PCR were used to analyse microbial communities in the rumen, reticulum, omasum, and abomasum of six domesticated yak. The diversity of prokaryotes was higher in reticulum and omasum than in rumen and abomasum. Bacteroidetes predominated in the four stomach compartments, with abundance gradually decreasing in the trend rumen > reticulum > omasum > abomasum. Microorganism composition was different among the four compartments, all of which contained high levels of bacteria, methanogens, protozoa and anaerobic fungi. Some prokaryotic genera were associated with volatile fatty acids and pH. This study provides the first insights into the microorganism composition of four stomach compartments in yak, and may provide a foundation for future studies in this area.

Bioactive polysaccharides and oligosaccharides as possible feed additives to manipulate rumen fermentation in Rusitec fermenters.

Bioactive polysaccharides and oligosaccharides (POSs) have been used as safe non-antibiotic alternatives in animal diets; however, only limited data are available on their effects in rumen manipulation. This study was undertaken to systematically evaluate and compare the efficacies of six different bioactive POSs (10g/kg diet) with respect to ruminal fermentation, feed digestibility, biohydrogenation and bacterial population using a rumen simulation technique. The experiment consisted of 4 independent 12-d incubation periods (each including 8 d for acclimation, followed with 4 d for sample collection). The results demonstrated that Lycium barbarum polysaccharide had no effect and Astragalus polysaccharide only increased the total VFA production. Chitooligosaccharide decreased the propionate proportion with a corresponding increase of acetate to propionate ratio. Fructooligosaccharide increased fatty acid biohydrogenation and the abundances of R. albus, B. fibrisolvens and S. ruminantium. Both Lentinan polysaccharide and xylooligosaccharide increased the total VFA production, fatty acid biohydrogenation and the abundance of B. fibrisolvens. In addition, Lentinan polysaccharide increased 48-h dietary protein degradation and the abundance of R. flavefaciens, while xylooligosaccharide increased 24-h dietary fiber degradation and the abundance of R. albus. In conclusion, bioactive POSs, especially Lentinan polysaccharide and xylooligosaccharide, can serve as potential feed additives to manipulate rumen fermentation.

Abomasal dysfunction and cellular and mucin changes during infection of sheep with larval or adult Teladorsagia circumcincta.

This is the first integrated study of the effects on gastric secretion, inflammation and fundic mucins after infection with L3 T. circumcincta and in the very early period following transplantation of adult worms. At 3 months-of-age, 20 Coopworth lambs were infected intraruminally with 35,000 L3; infected animals were killed on Days 5, 10, 15, 20 and 30 post-infection and 6 controls on either Day 0 or 30 post-infection. Another 15 Romney cross lambs received 10,000 adult worms at 4-5 months-of-age though surgically-implanted abomasal cannulae and were killed after 6, 12, 24 and 72 hours; uninfected controls were also killed at 72 hours. Blood was collected at regular intervals from all animals for measurement of serum gastrin and pepsinogen and abomasal fluid for pH measurement from cannulated sheep. Tissues collected at necropsy were fixed in Bouin's fluid for light microscopy, immunocytochemistry and mucin staining and in Karnovsky's fluid for electron microscopy. Nodules around glands containing developing larvae were seen on Day 5 p.i., but generalised effects on secretion occurred only after parasite emergence and within hours after transplantation of adult worms. After L3 infection, there were maximum worm burdens on Days 10-15 post-infection, together with peak tissue eosinophilia, inhibition of gastric acid secretion, hypergastrinaemia, hyperpepsinogenaemia, loss of parietal cells, enlarged gastric pits containing less mucin and increased numbers of mucous neck cells. After adult transplantation, serum pepsinogen was significantly increased after 9 hours and serum gastrin after 18 hours. Parallel changes in host tissues and the numbers of parasites in the abomasal lumen suggest that luminal parasites, but not those in the tissues, are key drivers of the pathophysiology and inflammatory response in animals exposed to parasites for the first time. These results are consistent with initiation of the host response by parasite chemicals diffusing across the surface epithelium, possibly aided by components of ES products which increased permeability. Parietal cells appear to be a key target, resulting in secondary increases in serum gastrin, pit elongation, loss of surface mucins and inhibition of chief cell maturation. Inflammation occurs in parallel, and could either cause the pathology or exacerbate the direct effects of ES products.

Effect of increasing the proportion of dietary concentrate on gastrointestinal tract measurements and brush border enzyme activity in Holstein steers.

The aim of this study was to determine the time course for adaptation of the reticulo-rumen, omasum, abomasum, and small intestine in response to an abrupt increase in the proportion of grain in the diet. Adaptive responses include tissue and digesta mass, small intestinal length, and brush border enzyme activity in the duodenum, proximal jejunum, and ileum. Twenty-five Holstein steers (213 ± 23 kg; 5 to 7 mo of age) were blocked by body weight, and within block were randomly assigned to 1 of 5 treatments: the control diet (CTRL; 92% chopped grass hay and 8% mineral and vitamin supplement on a dry matter basis) or a moderate grain diet (MGD; 50% chopped grass hay, 42% rolled barley grain, and 8% mineral and vitamin supplement) that was fed for 3 (MGD3), 7 (MGD7), 14 (MGD14), or 21 d (MGD21). Dry matter intake was limited to 2.25% of body weight to ensure that changes in dry matter intake did not confound the results. On the last day of the dietary exposure, steers were slaughtered 2 h after feeding. Reticulo-rumen tissue mass and ruminal epithelium mass in the ventral sac of the rumen were not affected by the MGD. Wet reticulo-ruminal digesta mass decreased from CTRL to MGD7 and then increased, but reticulo-ruminal digesta dry matter mass did not differ between treatments. Omasal mass, omasal tissue mass, and omasum digesta mass decreased linearly with the number of days fed MGD, but abomasal tissue mass tended to increase linearly. Duodenal tissue mass tended to increase linearly, and ileal length increased linearly with the number of days fed MGD. Lactase activity in the proximal jejunum increased linearly and maltase activity in duodenum tended to increase linearly with days fed MGD. Aminopeptidase N activity in the proximal jejunum increased cubically with days fed MGD, and dipeptidylpeptidase IV activity in ileum tended to decrease from CTRL to MGD14 and then tended to increase. Adaptation to a diet with a greater proportion of concentrate involves changes in the mass and length of regions of the gastrointestinal tract and brush border enzyme activity. These changes take place gradually over at least 3 wk.

Modified Beef Tongue Model for Fourth-Degree Laceration Repair Simulation.

BACKGROUND: An existing model for fourth-degree laceration repair uses beef tongue with plastic or vinyl tubing. This modified model substitutes beef tripe for the anal mucosa and chicken leg muscles for the anal sphincter muscle analogs to create a realistic model. METHOD: Tripe is tunneled through the body of the trimmed beef tongue and sutured like an ostomy to simulate the anal canal. The tongue is incised toward the tripe "anal canal." Chicken leg muscles are tunneled from the incision out to the cut edges of the beef tongue to create anal sphincter muscle analogs. Procedures can be repeated on the opposite side. Two double-sided models can be made per tongue. EXPERIENCE: The model can be refrigerated or frozen and thawed before use. A fourth-degree laceration can be cut immediately before use. Materials were obtained at a local supermarket for $5-7 per half-tongue, double-sided model. Residents responded positively to the model and stated that animal tissue provided realistic haptic simulation. CONCLUSION: The modified beef tongue model utilizing tripe and chicken leg muscles as anal mucosa and anal sphincter muscle analogs, respectively, provided excellent perceived haptic fidelity. Moreover, it is an innovative, inexpensive, and well-received teaching tool to augment resident education.

Defining risk for low reticuloruminal pH during the diet transition period in a commercial feedlot in western Canada.

The objective of the current study was to measure reticuloruminal pH in cattle in a commercial feedlot setting to determine the incidence and extent of low reticuloruminal pH for steers and heifers as they transition to a high-concentrate finishing diet. Reticuloruminal pH was measured in 16 "mixed breed" steers (4 steers/pen with 4 pens) and 16 "mixed breed" heifers (4 heifers/pen with 4 pens) housed in commercial feedlot pens, with 227 ± 13 and 249 ± 6 cattle/pen cohort steers and heifers, respectively, for the diet transition period. Cattle were transitioned from a diet of 53.5% forage and 46.5% concentrate to a diet of 9.5% forage and 90.5% concentrate on a DM basis using a 40-d transition with 5 dietary steps with the diets containing 41.4, 44.8, 49.8, 52.5, 55.1, and 64.0% nonfibrous carbohydrate. In addition, wheat replaced barley as the grain source during the dietary transition. Reticuloruminal pH was measured using orally administered pH measurement devices that were retrieved at slaughter. Data were analyzed using a mixed model including the fixed effects of sex, diet, and the 2-way interaction to evaluate the effect of diet and sex and with the fixed effects of sex, diet, and day relative to each dietary change along with the 2- and 3-way interactions to evaluate temporal responses as a result of diet change. A repeated measures statement was included for the effect of day. Both the mean and minimum reticuloruminal pH values decreased as the proportion of concentrate in the diet increased ( < 0.001). The area and duration that pH was <5.6 increased with greater inclusion of concentrate in the diet ( < 0.001). The number of cattle experiencing low reticuloruminal pH, defined as pH < 5.6 for >180 min, increased with increasing concentrate, and by the end of the 40-d dietary transition, 83% of the cattle had experienced at least 1 bout of low reticuloruminal pH, with most experiencing between 1 and 3 bouts/diet. These data are interpreted to suggest that cattle are at high risk for experiencing low reticuloruminal pH during the dietary transition but that the extent of low reticuloruminal pH is mild. Moreover, the data suggest that the risk for low reticuloruminal pH increases with increasing proportion of concentrate in the diet. The results also suggest that susceptibility to low reticuloruminal pH may differ between steers and heifers.

Further assessment of the protozoal contribution to the nutrition of the ruminant animal.

The flow of protozoa from the reticulo-rumen is lower than expected, due to ability of protozoa to prevent washout through sequestration on feed particles and the rumen epithelium. In order to estimate the distribution of protozoa within the reticulo-rumen and passage to the omasum, Czerkawski (1987) developed a model containing pools for the rumen liquid phase, rumen solid phase, and the omasum. This model was used to estimate loss of protozoa in the omasum as well as the amount of protozoal protein available to the animal in the lower gut. A number of assumptions were incorporated into the model, some of which appear unsupported by current research. This paper represents an update, revision, and re-evaluation of Czerkawski's model, where the assumptions that all protozoa in the 'attached' phase are in solid digesta, and that protozoa only leave the rumen in the liquid, have been relaxed. Therefore, the revised model allows for sequestration of protozoa on the rumen epithelium and protozoal passage with particulate outflow. Using experimental observations with inputs within biological limits, the revised model and Czerkawski's original model were verified. The effect of diet on the model was then assessed using inputs from a 100% forage diet and a 35-65% concentrate diet. The extent of sequestration was also varied from complete sequestration, to partial sequestration, and no sequestration. A sensitivity analysis was conducted through a linear regression of perturbed mean inputs versus outputs. The results from the revised model indicate that within the reticulo-rumen, the concentrate diet has a greater fractional flow rate of protozoa from the liquid to solid phase, but a lesser fractional flow rate back to the liquid phase, compared to the forage diet. As well, the concentrate diet has a slower net growth rate of protozoa in the attached phase, compared to the forage diet. In the omasum, the forage diet has a less negative net growth rate, compared to the concentrate diet. The forage diet was also associated with smaller loss of protozoa from the omasum. There are limited data from the omasum to be incorporated into the revised model, especially for quantity of protozoa in the omasum. Further research on quantification of protozoa in the omasum could strengthen the predictions made by the model. Despite this, the revised model found a loss of protozoa in the omasum similar to that suggested by Czerkawski's original model 65-73% versus 66%. The revised model results indicate that efforts to increase protozoal flow to the duodenum should focus on reduced sequestration and increased outflow rate from the rumen, although more research is needed to quantify protozoa in the omasum, and to investigate the role of sequestration onto the wall of the reticulo-rumen.

Behavior of sheep fed babassu cake (Orbygnia speciosa) as a substitution for elephant grass silage.

This study aimed to evaluate the behavior of sheep fed babassu cake as a substitution for elephant grass silage. The experiment was conducted at the Federal Rural University of Amazonia (Universidade Federal Rural da Amazônia - UFRA), Brazil, using 45 sheep housed in individual stalls, with unlimited access to feed and distributed in a completely randomized design with five treatments (0, 12.5, 25, 37.5 and 50% inclusion of babassu cake) and nine replications. All of the treatments contained a roughage-to-concentrate ratio of 40:60. No differences were observed in the time spent feeding (P > 0.05), regardless of the source of roughage used. However, there was a reduction in the time spent in rumination (P < 0.05) and an increase in time spent idling (P < 0.05) when babassu cake was included in the diet. Although there was a reduction in the time spent chewing the ruminal bolus (P < 0.05), the total daily chewing time was the same for all animals (P > 0.05). However, the sheep fed babassu cake showed higher feeding and rumination efficiency (P < 0.05). Therefore, the substitution of elephant grass silage with babassu cake can be performed at up to 50% without compromising the total time spent eating and chewing, which allows increased feeding and rumination efficiency.

Gross anatomy of the stomach of the dorcas gazelle (Gazella Dorcas, Linnaeus, 1758) / Anatomía macroscópica del estómago de la gacela dorcas (Gazella Dorcas, Linnaeus, 1758)

The macroscopic anatomy of the stomach in four adult dorcas gazelle was described. Four adult, two male and two female dorcas gazelle (Gazella dorcas) of the Frigya Zoological Park, Enfidha, Tunisie, were used in this study. The ruminal papillae were distributed unequally in the rumen, and were larger and more abundant within the atrium and in the two saccus cecus. The papillae were absent in dorsal part of the dorsal sac. The ruminal pillars had no papillae. The cellulae reticuli were divided and contained secondary and tertiary crests. The curvatura omasi measured 12.1±0.1 cm. A comparison with literature data for sand gazelles (Gazella subgutturosa marica) emphasises that differences between closely related species that fill similar niches cannot be expected to follow a clear pattern, but yield an inhomogenous picture, with some measurements more tending towards a specific feeding type in the one, and some other measurements tending more towards that feeding type in the other species.We concluded that the stomach morphology of the dorcas gazelle indicates the'cattle-type' morphophysiology representative for intermediate feeders.

En este estudio se describe la anatomía macroscópica del estómago de cuatro gacelas dorcas adultas. Se utilizaron cuatro animales adultos, dos machos y dos hembras (Gazella dorcas) del Parque Zoológico Frigya, Enfidha, Túnez. Las papilas ruminales estaban distribuidas de manera desigual en el rumen, y se observaron de mayor tamaño y abundantes dentro de la aurícula, y en ambos saccus cecus. No se observaron papilas en la parte dorsal del saco dorsal. Los reticuli cellulae se dividieron y contenían crestas secundarias y terciarias. La curvatura omasi media 12,1±0,1 cm. Una comparación con los datos de la literatura en gacelas de arena (Gazella subgutturosa marica) indica que no se puede esperar un patrón exacto en las especies estrechamente relacionadas que llenan nichos similares, pero no cuentan con una imagen homogénea. En algunas de las mediciones se observa la tendencia hacia un tipo específico de alimentación en una especie, mientras que otras medidas tienden a asociar este tipo de alimentación a otras especies. La morfología del estómago de la gacela dorcas indica que la morfofisiologia de este tipo de ganado es representativa de alimentadores intermedios.

Surgery of the Forestomach.

Indications for rumen surgery include rumen tympany (bloat), toxic plant ingestion, to provide enteral nutrition, to perform elective cannula placement, and to access other forestomach compartments (reticulum/omasum). The rumen is a highly contaminated viscus and special care should be taken to avoid peritoneal contamination from rumen contents. Diseases causing forestomach dysfunction and surgical procedures on the forestomach compartments are discussed here.