Morphological and functional development of the rumen in the calf: influence of the time of weaning. 1. Morphological development of rumen mucosa.

The objective of this study was to determine whether the nutritional regimen of rearing calves would influence the morphometric and histological development of rumen mucosa. Twelve male Holstein calves 7 d of age were assigned to three groups of 4 animals each: milk group (I), early weaned (6 weeks) group (II) and late weaned (9 weeks) group (III). All animals received additional solid feed. Animals of group I were slaughtered after 6 weeks of age, whereas those in groups II and III were slaughtered after 9 weeks of age. At slaughter, the ruminal digesta amounted to 2035 g (milk group), 3092 g (late weaned group) and 5374 g (early weaned group). The differences in the ruminal molar percentage of SCFA were not significant. There was a trend for lower pH and higher SCFA concentrations in the order late weaned, early weaned and milk fed animals (pH: 6.4, 6.6 and 6.7, respectively; SCFA: 96, 87 and 77 mmol/l, respectively). The mean length (1.07 mm in milk group, 1.45 mm in late weaned group and 1.87 mm in early weaned group), width (0.43, 0.58 and 0.71 mm, respectively) and surface of papillae (190, 232 and 241 mm2/cm2 mucosa, respectively) increased with both the age of the animals and the elevated intake of solid feed, whereas the number of papillae (210, 140 and 92 per cm2 mucosa, respectively) decreased. In both milk-fed groups type A and B corneal cells were present in the Stratum corneum, whereas in the earlier weaned calves type C-cells could be also seen. These findings indicate a more advanced stage of development of the rumen epithelium in the earlier weaned calves fed higher amounts of concentrate and hay.     

Butyric acid stimulates rumen mucosa development in the calf mainly by a reduction of apoptosis.

In ruminants the stimulation of papillar growth by butyric acid is well described but effects on mitosis and apoptosis are not known. To clarify the effect of short chain fatty acids three groups of three calves received a basic ration of 100 g hay per day for 6 weeks and additionally milk replacer. From these, two groups were fed with increasing amounts of the salts of either propionic acid (53 to 390 g) or butyric acid up to (54 to 326 g). The control group instead received an additional isocaloric amount of milk replacer. Mitosis was characterized by Ki67 immunoreactivity, apoptosis by a modified TUNEL assay and by electron microscopy. The feeding regimes led to significant differences of papillar length, increasing from 1.0 mm (controls) to 2.2 mm (propionic acid) and 4 mm (butyric acid). This enlargement was partly explained by an increased mitotic rate for the two fatty acid groups. The difference between the fatty acid groups was mainly explained by different apoptotic rates which were only one third for butyric acid compared to propionic acid (P < 0.001). In conclusion, butyric acid is a specific inhibitor of ruminal apoptosis in vivo.     

延胡索酸二钠对断奶羔羊瘤胃发育及瘤胃发酵功能的影响

为了研究日粮中添加延胡索酸二钠对断奶羔羊瘤胃发育及瘤胃发酵功能的影响,选用30只日龄为(50±5)d、体重为(25±2)kg的公羔,随机分为3组,每组10只。对照组饲喂基础日粮,试验组在基础日粮的基础上添加0.5%(Ⅰ组)和1%(Ⅱ组)的延胡索酸二钠,试验期70 d。结果显示:1试验Ⅰ、Ⅱ组断奶羔羊体增重比对照组分别增重3.2%(P0.05)和55.5%(P0.05);试验Ⅰ、Ⅱ组瘤胃净重比对照组分别高8.5%(P0.05)和26.4%(P0.01),Ⅰ和Ⅱ组间差异显著(P0.05);试验Ⅰ、Ⅱ组断奶羔羊瘤胃乳头高度比对照组分别高8.2%和9.2%,Ⅱ组乳头密度比对照组降低16.2%,各组间差异均不显著(P0.05)。2Ⅰ和Ⅱ组瘤胃p H值比对照组高(P=0.08);Ⅰ和Ⅱ组瘤胃氨态氮(NH3-N)浓度比对照组分别降低29.7%(P0.05)和21.0%(P0.05);Ⅰ和Ⅱ组瘤胃内容物中乳酸浓度分别比对照组降低27.0%(P0.01)和19.5%(P0.01);乙酸、丙酸、丁酸、乙酸/丙酸和总挥发性脂肪酸(TVFA)浓度3组间差异不显著(P0.05)。结果提示:日粮中添加延胡索酸二钠提高了断奶羔羊的体增重及瘤胃净重和瘤胃p H值,降低了瘤胃内氨态氮及乳酸浓度。     

Effects of protozoa on methane production in rumen and hindgut of calves around time of weaning.

Effects of the presence or absence of ciliate protozoa on methanogenesis in the rumen and hindgut were investigated in young calves during a 7-week period. Ten Holstein calves, aged 7 days, were divided in two groups (n = 5) and fed an increasing amount of a commercial milk replacer and small amounts of a calves starter. One group was inoculated with ciliate fauna on two occasions, week 5 and 6, while the second remained ciliate-free. The absence of protozoa in the rumen decreased rumen empty weight (-23%, P < 0.01), and rumen pool size of N (-36%, P < 0.01) and crude fat (-37%, P < 0.05). Rumen bacteria of non-faunated calves contained a higher proportion of total amino acid-N per 16 g N (+3%, P < 0.01) and D-alanine-N per 16 g N (+13%, P < 0.05) compared to faunated calves. Further results contain a reference for a higher bacterial mass in the ciliate-free rumen with an increased number of bacteria adherent to rumen mucosa. The CH4 production in the rumen increased exponentially with the increase in protozoa population size (R2 = 0.68). In presence of 46 x 10(4) protozoa per ml rumen fluid, the in vitro CH4 production of rumen fluid per mol total VFA was about 34% higher in faunated than in non-faunated calves (P < 0.001). Hydrogen (2H) recovery of rumen fermentation was positively correlated (R2 = 0.55) to the CH4 production rate. Methanogens were attached on rumen mucosa. Methanogenesis, induced by rumen mucosa attached bacteria, was stimulated by ruminal protozoa. In the absence of protozoa in the rumen, the acetate-propionate ratio and butyrate proportion of VFA were reduced. In vivo, in the absence of protozoa not only the whole animal CH4 production (-30%, P < 0.05) but also the digestibility of carbohydrates (-4%, P < 0.05) was reduced. Thereby no difference was observed in the intake of ME per kg DM between the groups. In conclusion, the methanogenesis in the rumen, but not in hindgut, is associated with the development of the ruminal protozoa population. The level of methanogenesis (mol/mol VFA) in the hindgut amounts to 20% of the ruminal methanogenesis.     

Postnatal development of nutrient transport in the intestine of dogs

OBJECTIVE: To measure nutrient absorption by the intestine during postnatal development of dogs. ANIMAL: 110 Beagles ranging from neonatal to adult dogs. PROCEDURE: Rates of absorption for sugars (glucose, galactose, and fructose), amino acids (aspartate, leucine, lysine, methionine, and proline), a dipeptide (glycyl-sarcosine), and linoleic acid by the proximal, mid, and distal regions of the small intestine were measured as functions of age and concentration (kinetics) by use of intact tissues and brush-border membrane vesicles. Absorption of octanoic acid by the proximal portion of the colon was measured in intact tissues. RESULTS: Rates of carrier-mediated transport by intact tissues decreased from birth to adulthood for aldohexoses and most amino acids but not for fructose and aspartate. Kinetics and characteristics of absorption suggest that there were changes in the densities, types, and proportions of various carriers for sugars and amino acids. Saturable absorption of linoleic acid in the small intestine and octanoic acid in the proximal portion of the colon increased after weaning. CONCLUSIONS AND CLINICAL RELEVANCE: Rates of absorption decreased between birth and adulthood for most nutrients. However, because of intestinal growth, absorption capacities of the entire small intestine remained constant for leucine and proline and increased for glucose, galactose, fructose, aspartate, and proline but were less than predicted from the increase in body weight. Although postnatal ontogeny of nutrient absorption was consistent with changes in the composition of the natural and commercial diets of growing dogs, rates of amino acid and peptide absorption were lower than expected.     

不同日粮组成下高寒地区小黑麦在断奶初期奶公犊瘤胃内动态降解的研究

用3头3月龄左右、装有瘤胃瘘管的荷斯坦奶公犊,按3×3完全拉丁方试验设计,喂给三种日粮,日粮组成按精粗比分别为:Ⅰ组,70:30;Ⅱ组,60:40;Ⅲ组,50:50,研究不同日粮组成下高寒地区小黑麦的DM、CP以及NDF在断奶初期奶公犊瘤胃内动态降解。试验结果表明:日粮精粗比为60:40时,其CP的降解率和降解参数明显低于精粗比为70:30和50:50的日粮,差异显著(P<0.05);其DM和NDF的降解率和降解参数明显高于精粗比为70:30和50:50的日粮,差异显著(P<0.05)。     

Administration of p.g. 600 to sows at weaning and the time of ovulation as determined by transrectal ultrasound

This study determined whether the interval from estrus to ovulation was altered by giving P.G. 600 to sows at weaning. Mixed-parity sows received P.G. 600 i.m. (n = 72) or no treatment (n = 65) at weaning (d 0). Beginning on d 0, sows were observed for estrus twice daily. At the onset of estrus and thereafter, ultrasound was performed twice daily to determine the average size of the largest follicles and time of ovulation. Weaning age (20.1+/-0.4 d) did not differ (P > 0.10) between treatments. More P.G. 600 sows expressed estrus within 8 d (P < 0.01) than controls (94.4% vs 78.4%, respectively). Parity was associated with expression of estrus (P < 0.02), with 78% of first-parity and 93% of later-parity sows exhibiting estrus. However, no treatment x parity effect was observed (P > 0.10). The interval from weaning to estrus was reduced (P < 0.0001) by P.G. 600 compared with controls (3.8+/-0.1 d vs 4.9+/-0.1 d). Follicle size at estrus was not affected by treatment (P > 0.10). The percentage of sows that ovulated did not differ (P > 0.10) for P.G. 600 and control sows (90.3% vs 81.5%, respectively). Time of ovulation after estrus was not affected by treatment and averaged 44.8 h. However, univariate analysis indicated that the interval from weaning to estrus influenced the interval from estrus to ovulation (r = 0.43, P < 0.0001). Further, multivariate analysis showed an effect of treatment on the intervals from weaning to estrus, weaning to ovulation (P < 0.0001), and estrus to ovulation (P < 0.04). Within 4 d after weaning, 81% of the P.G. 600 sows had expressed estrus compared with 33% of controls. However, this trend reversed for ovulation, with only 35% of P.G. 600 sows ovulating by 36 h after estrus compared with 40% of controls. The estrus-to-ovulation interval was also longer for control and P.G. 600 sows expressing estrus < or = 3 d of weaning (45 h and 58 h, respectively) than for sows expressing estrus after 5 d (39 h and 32 h, respectively). Farrowing rate and litter size were not influenced by treatment. However, the interval from last insemination to ovulation (P < 0.02) indicated that more sows farrowed (80%) when the last insemination occurred at < or = 23 to > or = 0 h before ovulation compared with insemination > or = 24 h before ovulation (55%). In summary, P.G. 600 enhanced the expression of estrus and ovulation in weaned sows but, breeding protocols may need to be optimized for time of ovulation based on the interval from weaning to estrus.     

Energy metabolism in young pigs as affected by establishment of new groups prior to transport

Energy metabolism was studied in 9-week-old-pigs as affected by mixing just before transport. In each of three trials, two groups of 20 pigs (two litters of 10) were randomly assigned to one of two treatments: control and mixing. Each group was housed in one of two climatic chambers with each subgroup in one of two pens. In each trial, the two litters within the mixing treatment were mixed, just before transport, at the start of a 2-week experimental period. In the control treatment, the social structure of both litters in each trial was not altered. In both treatments, large alterations of energy partitioning from week 1 to week 2, are probably signs of recovering from transportation and/or adaptation to new feeding and housing conditions. Mixing just before transport did not change total energy metabolism but only increased nonactivity-related heat production by 3.1% for the total experimental period. Most likely, long-term performance is also not affected negatively by mixing. Animals seem to be able to change energy expenditure on activity when more energy is required for other physiological processes. This symptom of possible reallocation of energy between different vital live processes (e.g. behavior, protein turn-over) might be one of the first indications of an impaired well-being.     

Ground transport stress affects bacteria in the rumen of beef cattle: A real‐time PCR analysis

Transport stress syndrome often appears in beef cattle during ground transportation, leading to changes in their capacity to digest food due to changes in rumen microbiota. The present study aimed to analyze bacteria before and after cattle transport. Eight Xianan beef cattle were transported over 1000 km. Rumen fluid and blood were sampled before and after transport. Real‐time PCR was used to quantify rumen bacteria. Cortisol and adrenocorticotrophic hormone (ACTH) were measured. Cortisol and ACTH were increased on day 1 after transportation and decreased by day 3. Cellulolytic bacteria (Fibrobacter succinogenes and Ruminococcus flavefaciens), Ruminococcus amylophilus and Prevotella albensis were increased at 6 h and declined by 15 days after transport. There was a significant reduction in Succinivibrio dextrinosolvens, Prevotella bryantii, Prevotella ruminicola and Anaerovibrio lipolytica after transport. Rumen concentration of acetic acid increased after transport, while rumen pH and concentrations of propionic and butyric acids were decreased. Body weight decreased by 3 days and increased by 15 days after transportation. Using real‐time PCR analysis, we detected changes in bacteria in the rumen of beef cattle after transport, which might affect the growth of cattle after transport.     

Metabolic and luteal function in winter‐calving Spanish beef cows as affected by calf management and breed

This experiment aimed at evaluating the effect of calf management and breed on the metabolic and luteal function of post‐partum beef cows fed at maintenance. Fifty multiparous cows, 22 Parda de Montaña (PA) and 28 Pirenaica (PI), were assigned to either suckling once‐daily for 30 min (RESTR) or ad libitum (ADLIB) from the day after calving. Blood samples were collected to analyse metabolites [non‐esterified fatty acids (NEFA), β‐hydroxybutyrate, total protein and urea)], insulin‐like growth factor‐I (IGF‐I) and progesterone (P4) at different intervals. Cows from RESTR maintained their live‐weight (LW) over the first 3 months post‐partum, whereas ADLIB cows lost nearly 4% LW. Both genotypes showed similar LW gains during this period (p > 0.10). Calf daily gains were lower in RESTR than in ADLIB treatment (p < 0.05), but similar across breeds (p > 0.10). Milk and lactose production were lower in RESTR cows than in ADLIB (p < 0.05). Milk and protein yield were greater in PA than in PI breed (p < 0.05). Serum NEFA, total protein and urea were higher in PI cows suckling ADLIB than in the rest (p < 0.05). Cows from PI breed had greater NEFA values than PA ones on the first week post‐partum (p < 0.001). Circulating IGF‐I was not affected by suckling frequency, breed nor their interaction (p > 0.10). Suckling frequency, but not breed, affected the interval from calving to first ovulation (p < 0.001), being shorter in RESTR than in ADLIB cows. In conclusion, the ad libitum suckling practice improved cow milk yield and offspring gain compared to once‐daily suckling for 30 min from the day after calving, at the expense of impairing the onset of cyclicity. The effect of calf management was confounded with breed on the studied blood biochemical constituents, but any of these metabolites influenced the role of endocrine IGF‐I in these genotypes.     

Anomalous development of the spinal cord in a calf.

A full term Friesian bull calf was born unable to stand. The dam had no signs of illness during pregnancy. In the thoracic spinal cord there was anomalous development of the central canal and a dorsally placed fusiform and longitudinal dilatation. Mild inflammatory lesions were seen in some body organs and central nervous system where they were suggestive of viral infection. Several skeletal muscles had an extended range of muscle cell cross sectional areas and some cells had numerous internal nuclei.     

In vitro gas production in rumen fluid of buffalo as affected by urea‐calcium mixture in high‐quality feed block

This study aimed to determine the effect of urea‐calcium sulphate mixture (U‐cas) levels in high‐quality feed block (HQFB) on ruminal digestibility, fermentation and gas kinetics in rumen fluid of swamp buffalo by using in vitro techniques. The treatments were seven levels of U‐cas incorporated in HQFB at 0, 3, 6, 9, 12, 15 and 18% and the experimental design was a completely randomized design. Gas production rate constants for the insoluble fraction, potential extent of gas and cumulative gas were linearly increased with increasing levels of U‐cas in HQFB. The in vitro dry matter digestibility, in vitro organic matter digestibility, true digestibility and microbial mass were altered by treatments and were greatest at 18% U‐cas supplementation. Concentrations of propionate were linearly increased with increasing levels of U‐cas and was highest with U‐cas supplementation at 18%. The NH₃–N concentration was highest when urea was added in the HQFB while NH₃–N concentration tended to be reduced with increasing level of U‐cas. The findings suggest supplementation of 18% U‐cas in HQFB improves kinetics of gas production, rumen fermentation, digestibility and microbial mass as well as controlling the rate of N degradation in the rumen of swamp buffalo.     

The comparative effectiveness of three commercial oral solutions in correcting fluid, electrolyte and acid-base disturbances caused by calf diarrhoea.

Three commercial oral rehydration solutions (Effydral ('E'), Lectade ('L') and Lectade Plus ('LP')) were evaluated in young calves with diarrhoea following the administration of E. coli. Twenty calves with non-fatal diarrhoea were included in each group and examined for electrolytes, acidosis (pH, PCO2 and TCO2), PCV and selected biochemical parameters. Faecal consistency and clinical state were also assessed. Eight calves were examined for plasma and ECF volume. Calves were treated with the appropriate ORS only for 2 days and with ORS plus milk substitute for a further 2 days. No other treatments were given. Solutions E, L and LP were chosen specifically to test the hypothesis that their ability to repair extracellular volume would depend on their sodium content (E > L > LP) and their ability to correct metabolic acidosis would reflect their content of bicarbonate precursor (E > LP > L). Both hypotheses were confirmed as was the fact that the higher sodium content of E helps it to repair ECF volume without predisposing to hypernatraemia. The importance of correcting hyponatraemia as well as ECF volume is emphasized. Direct measurement of such changes proved much more sensitive than traditional clinical parameters such as weight loss, skin elasticity, etc. Although this study was not designed to examine mortality, it is noted that nine treated calves died, none in the E-treated group.     

Technical note: development of a duodenal cannula for sheep.

A single T-shaped duodenal cannula of silicone rubber with a gutter-type small inner flange was developed for sheep. The barrel of the cannula was 24 mm long with an internal diameter of 12 mm. A polyester surgical mesh (100 mm x 100 mm) was connected to the barrel of the cannula as an anchor. Fibrous tissues grew on the polyester mesh anchor and adhered firmly to the serosa of the intestine, thus leaving no gap and, hence, preventing any leakage of intestinal contents from the side of the fistula. The small (24 mm in diameter) and thin (3 mm in thickness) outer flange of the cannula became buried in the wool and prevented any mechanical disturbance of the cannula by the activity of the animal. The elasticity of the silicone rubber prevented distortion of the duodenum around the barrel of the cannula. No erosion of the tissue between the inner flange of the cannula and the mesh was seen in postmortem observations.     

Physiological and immunological responses to weaning and transport in the young pig: modulation by administration of porcine somatotropin

To examine the effects of exogenous porcine (p) ST on measures of stress and immune function in weaned pigs with or without transport, pigs (20 +/- 1 d of age) received daily injections of pST (0.5 mg/kg; n = 16) or saline (n = 16) for 5 d. On d 5, a blood sample was collected immediately before injection. At 4 h postinjection, pigs were weighed, sampled for blood, injected with di-nitrophenyl-conjugated keyhole limpet hemocyanin, and weaned. One half of the pigs in each group were transported for 3 h before placement in the nursery. Pigs were weighed, and blood was collected on 1, 7, and 14 d postweaning. Statistical significance was set at P < 0.05. Serum IGF-I concentrations were increased by pST and decreased by weaning, but not affected by transport. The free cortisol index was elevated in all pigs 1 d postweaning, although less in transported versus nontransported pigs. By 7 d postweaning, the free cortisol index returned to prewean values. Serum concentrations of immunoglobulin (Ig) G increased in all pigs by 14 d postweaning, but were not affected by pST or transport. Serum IgM concentrations were elevated at 7 and 14 d postweaning. Before weaning and again 1 d postweaning, pigs treated with pST had greater concentrations of IgM than did control animals. Circulating neutrophils increased in pST-treated pigs 4 h after the final pST injection. Improved immune function in weaned pigs by pST may lead to greater health and growth in a commercial setting.     

Research note: effect of increasing dietary concentrate levels on microbial biotin metabolism in the artificial rumen simulation system (RUSITEC).

The effect of varying hay/barley-proportions in the feed ration on biotin metabolism of rumen microbes was studied by means of the rumen simulation technique RUSITEC. The stepwise replacement of hay by barley decreased dietary biotin and the net output of biotin by the microbial metabolism. It is concluded that rumen microbes utilise more and/or synthesize less biotin with increasing proportions of dietary barley. These results indicate that a critical reconsideration of current views with regard to the supply and requirement of the high yielding dairy cow for biotin is necessary.