Indigestion in Young Calves

Increasing the lactose content of different milk replacers or milk diets by approx. 30 % of the dry matter increased the frequency of diarrhoea the first 10–12 days in young calves on all occasions in 5 experiments comprising 120 calves. For all diets taken together, this effect was highly significant. Total daily intakes of lactose amounted to 200–480 g. When lactose was given on top of the milk rations, the growth rate increased significantly, whereas the growth rate was usually insignificantly reduced when lactose replaced other nutrients in milk diets or milk replacers, their levels of protein and fat becoming low. Albumin and total protein in blood plasma were significantly lower when the dietary protein level was low. Milk replacers with 20 or 40 % whey powder, replacing skim milk powder, performed equally well, but gave significantly less growth than the old-fashioned feeding of whole milk-skim milk. Intake of hay and barley and a number of clinical and histological or pathological parameters did not vary consistently with dietary level of whey powder or lactose. Feeding whole milk all the time resulted in low intake of hay and barley and poorly developed forestomachs, but high dressing-out %. Substituting soya for part of the skim milk powder in milk replacers gave abomasal content with no curds. In most cases, pH in the rumen appeared to be nearly up to neutral until the calves ate ground barley, about 1 month old.     

Effect of alfalfa hay and starter feed supplementation on caecal microbiota and fermentation,growth, and health of yak calves

The caecum is the primary site where microbial fermentation and acidosis occurred. The supplementation of starter feed and alfalfa hay has the potential to influence caecal microbiota and then affect caecal fermentation. This study aims to investigate the effect of starter feed and alfalfa hay supplementation on caecal microbiota, immune homeostasis, and growth of preweaning yaks. Twenty 30-day-old male yak calves were randomly assigned to four groups, which separately fed with milk replacer (CON group), milk replacer with alfalfa hay (A group), milk replacer with starter feed (S group), and milk replacer with starter feed plus alfalfa hay (SA group) throughout the trial. Growth performance and plasma physiological and biochemical indicators were measured every 30 days. Calves were sacrificed at 120 days of age. The caecal contents were collected for measuring pH and contents of volatile fatty acids (VFAs) and lipopolysaccharide (LPS) and for characterizing caecal microbiota. The results indicated that individual or simultaneous supplementation with alfalfa hay and starter feed all significantly increased the BW, body height, body length, and chest girth of yak calves. However, supplementation with starter feed significantly increased plasma cortisol, nitric oxide, tumor necrosis factor-α, and interferon-γ concentrations and the ratio of aspartate aminotransferase to alanine aminotransferase of yak calves when compared with the control and alfalfa hay feeding groups, while the co-supplementation of starter feed and alfalfa hay could significantly decrease these inflammation-related indices when compared with the starter feeding group. Sequencing of the 16S rRNA gene showed that starter feed and alfalfa hay separately stimulated the proliferation of starch-decomposing and cellulose- or hemicellulose-decomposing bacteria. This also significantly increased the levels of acetate, propionate, butyrate, valerate, isobutyrate, and isovalerate in the caecal contents. Furthermore, compared with the S and CON groups, the significantly increased genera of Desulfobulbus, Olsenella, Pseudoflavonifractor, and Stomatobaculum in the SA and A groups were beneficial to the immune homeostasis, and the significantly decreased Blautia, Clostridium IV, Bacteroides, Eubacterium, Clostridium XVIII, and Mogibacterium in the SA and A groups were related to the reduced caecal lactate and LPS contents, the decreased inflammatory reaction, and the improved healthy hepatic condition of yak calves. In conclusion, milk replacer supplemented with alfalfa hay and starter feed is recommended during preweaning to improve yak calf health and growth because this regimen promotes the growth and maintains the immune homeostasis of yak calves.     

Indigestion in Young Calves

Fiftysix calves, in 2 similar experiments, were given 1 of 4 diets including a high lactose milk replacer: ground barley (GB), ground barley plus coarse hay (GB + GH), coarse hay (CH) and the liquid diet only (NS) ; the 2 last diets were held as controls. The calves were on the experimental diet from 1–2 weeks of age until slaughtered at 7-8 weeks of age. As observed by stereo-microscopy, the ruminai papillae in calves fed on GB were thickened, mostly finger- or club-shaped and sometimes nodular; nodular papillae were always arranged on prominent mucosal folds. Scattered nodular papillae had white coats. For calves fed on GB + CH the papillae were mostly finger- or tongue-shaped. Histologically papillae in calves fed on GB had hyperplasia of secondary papillae and epithelial layers. Microabscesses associated with penetrating hairs were frequent, and some calves had dyskeratosis with infiltration of polymorphonuclear leucocytes at the apex of papillae, identified as the white coats. For calves given GB+CH, abscesses and apical dyskeratosis were absent and the hyperplasia of epithelial layers milder than in the case of the GB diet. An ameliorative effect of hay on papillary changes caused by barley is indicated.     

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

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).     

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

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 × 4 Latin square design with four 21-day periods. The experiment was a 2 × 2 factorial arrangement with two levels of theoretical PS of AH (fine = 15 mm or long = 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 = 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 = 0.04). Moreover, the feeding of long AH resulted in longer time spent eating (P = 0.03) and higher pH (P < 0.01), as well as a tendency for higher acetate-to-propionate ratio in the rumen fluid (P = 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.     

Ground,dry-rolled and steam-processed barley grain for midlactation Holstein cows

Fine grinding of barley grain has traditionally been considered to be a potential risk to rumen function, feed intake and milk yield. These concerns are thought to be reduced by steam-rolling or coarse dry rolling. We hypothesized that finely ground barley grain is as effective in stimulating feed intake and milk production as are dry- and steam-rolled barley grain, and so the objective was to determine effects of feeding either (1) finely ground, (2) steam-rolled, (3) finely dry-rolled, or (4) coarsely dry-rolled barley grain on rumen fermentation, digestibility and milk yield and composition. Eight multiparous midlactation Holstein cows were used in a replicated 4×4 Latin square design experiment with four periods of 21 d. Diets contained 256 g barley grain/kg on a dry matter (DM) basis. Processing method did not affect milk yield and composition, DM intake, rumen pH and volatile fatty acids, fecal and urine pH, and apparent total tract nutrient digestibility. Results suggest that finely ground barley grain is no different than dry-rolled and steam-rolled barley grains in stimulating feed intake and productivity of midlactation cows, when 256 g of dietary DM/kg is barley grain.     

Indigestion in Young Calves

Two experiments comprising 24 calves, lasting 44–46 days, have been carried out in order to examine the influence of powders from heat-treated skim milk and whey on indigestion in young calves. The frequency of diarrhoea increased much (P < 0.01) in the first experiment when feeding the heat-treated products, but little in the other. Possible reasons for this difference are discussed. Calves fed heat-treated products in the first experiment consumed 13.8 1 of electrolyte fluid per head per day 14–22 days after commencing the test, when both diarrhoea and fluid consumption reached peak values. It is postulated that some of the calves might have succumbed without electrolyte fluid.     

Effects of nutritional conditions around weaning on carbonic anhydrase activity in the parotid gland and ruminal and abomasal epithelia of Holstein calves

Thirty-two male Holstein calves were used to investigate the effects of nutritional conditions around weaning and aging on carbonic anhydrase (CA) activity in the parotid gland and epithelium from the rumen and abomasum. We fed calf starter and lucerne hay as well as milk replacer (group N) or fed milk replacer either with (group S) or without (group M) administration of short-chain fatty acids (SCFA) through polypropylene tubing into the forestomach until 13 weeks of age. The diets were fed at 1000 hours and 1600 hours, and SCFA were administrated after milk replacer feeding at 1600 hours. Slaughter and tissue sampling were carried out between 1300 hours and 1430 hours at 1, 3, 7, 13, and 18 weeks of age. Tissue samples from five adult (1.5-2.0 years-old) Holstein steers were obtained from a local abattoir. In group N, CA activity in the parotid gland gradually and significantly increased toward the adult value, whilst in the epithelium from the rumen and abomasum, adult values were reached at 3 and 7 weeks of age, respectively. At 13 weeks, the activity for group N was significantly higher than that for the other two groups in the parotid gland, but there was no significant difference in the epithelium from the rumen and abomasum. The concentration of the carbonic isozyme VI in the parotid gland also changed with age but, in contrast to CA activity, had not reached adult levels by 13 weeks of age. In groups M and S, parotid saliva did not show any change toward an alkaline pH or toward a reciprocal change in the concentrations between Cl(-) and HCO(3)(-), even at 13 weeks of age. From these results we conclude that a concentrate-hay based diet around weaning has a crucial role in CA development in the parotid gland, but not in the epithelium of the rumen and abomasum.     

Estimation of milk leakage into the rumen of milk-fed calves through an indirect and repeatable method

In milk-fed calves, quantification of the milk that enters the rumen (ruminal milk volume, RMV) because of malfunction of the esophageal groove reflex may explain part of the variability observed between animals in their growth performance. The RMV can directly be quantified by adding an indigestible marker to the diet and measuring its recovery in the rumen at slaughter, but this technique cannot be repeated in time in the same animal. The objective of the study was to evaluate three indirect methods for estimating RMV. The first method was based on the assumption that ruminal drinking delays and limits acetaminophen appearance in blood after ingestion of milk supplemented with acetaminophen. The second method was based on a negative linear relationship between RMV and urinary recovery of non-metabolizable monosaccharides (3-O-methylglucose, l-rhamnose and d-xylose) added to the milk, owing to rumen fermentation. In the third method, RMV was calculated as the difference between total milk intake and the increase in abomasal milk volume (AMV) at feeding, measured through ultrasonography shortly after feeding, or estimated from the mathematical extrapolation of AMV to feeding time, based on consecutive measurements. These methods were tested in three experiments where calves (n=22, 10 and 13) were bucket fed or partly tube fed (i.e. by inserting milk replacer into the rumen via a tube to mimic ruminal drinking). In addition, Co-EDTA and Cr-EDTA were used as an indigestible marker in one experiment to trace bucket-fed or tube-fed milk replacer, respectively, to measure RMV. The relationship between AMV measured by ultrasonography and AMV measured at slaughter improved when kinetics of AMV were extrapolated to the time of slaughter by mathematical modeling (error between predicted and measured AMV equaled 0.49 l). With this technique, RMV during feeding averaged 17% and 24% of intake in Experiments 2 and 3, respectively. Plasma acetaminophen kinetics and recovery of non-metabolizable monosaccharides in urine were partly associated with ruminal drinking, but these techniques are not considered quantitatively accurate without further information of rumen degradation and absorption. The recovery of indigestible marker measured at slaughter gave a quantitative estimate of RMV (2% in Experiment 3), but improper measurement of emptying rate of fluid from the rumen may lead to underestimation. In conclusion, measuring changes in AMV by ultrasonography, in response to milk feeding, was the most promising indirect method to quantify RMV in veal calves.     

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 · 10⁴ 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.     

Effects of lactoferrin feeding on growth,feed intake and health of calves

Abstract

Lactoferrin (LF) exhibits a broad spectrum of anti-microbial properties and may have regulatory functions in the immune system. In the present study, 40 calves (20 males, 20 females) were used to examine the effects of supplemental bovine LF added to colostrum and milk replacer (at 0.16%) on health, weight development and feed intake during a 70-day experimental period. The calves were allocated to a treatment group (n = 20) and a control group (n = 20); the groups were balanced in terms of sex, live weight and date of birth. Body weight and feed intake were measured at regular intervals. Blood and colostrum samples were collected to determine the content of IgG. In addition, colostrum and milk replacer samples were analysed for their LF concentrations. Significantly higher IgG values were observed in the LF treated than in the control group during the entire feeding experiment from week 2 to week 6. Calves receiving LF had less days of disease with less serious cases of diarrhoea than the control group. Body weight and feed intake were not significantly different between the treatments; in male calves LF-treated animals tended towards higher weight gains. This study indicates that LF is advantageous for health and may therefore be a beneficial supplement in the diets for neonatal calves.     

Utilization of raw or heat-treated starch fed in liquid diet to pre-ruminants. 1. Calves.

Five 7-day-old Frisian bull calves, raised in Israel received twice a day a mixture of 40 g of soybean concentrate (65% protein) and 80 g of one of the following carbohydrates: glucose (G), expanded (heat-treated) (ES) or untreated (US) corn starch. In the afternoon the calves received in addition 400 g of milk replacer. Until weaning at experimental day 25, ES calves showed better growth and food utilization than their counterparts. Daily weight gain for the entire growing period up to slaughter was higher for the starch than for the glucose-fed group (P less than 0.05 for ES vs G). Heat treatment of starch increased its in vitro availability to amylase and its in vivo digestibility. Bypass of the rumen was complete in all G calves. In the ES and US groups, partial diversion of the liquid feed into the rumen was evident. The G group showed hyperglycemia after meals, while almost no increase in blood glucose level was observed after soy-starch meals (either US or ES).     

Effects of lactoferrin feeding on growth, feed intake and health of calves

Lactoferrin (LF) exhibits a broad spectrum of anti-microbial properties and may have regulatory functions in the immune system. In the present study, 40 calves (20 males, 20 females) were used to examine the effects of supplemental bovine LF added to colostrum and milk replacer (at 0.16%) on health, weight development and feed intake during a 70-day experimental period. The calves were allocated to a treatment group (n = 20) and a control group (n = 20); the groups were balanced in terms of sex, live weight and date of birth. Body weight and feed intake were measured at regular intervals. Blood and colostrum samples were collected to determine the content of IgG. In addition, colostrum and milk replacer samples were analysed for their LF concentrations. Significantly higher IgG values were observed in the LF treated than in the control group during the entire feeding experiment from week 2 to week 6. Calves receiving LF had less days of disease with less serious cases of diarrhoea than the control group. Body weight and feed intake were not significantly different between the treatments; in male calves LF-treated animals tended towards higher weight gains. This study indicates that LF is advantageous for health and may therefore be a beneficial supplement in the diets for neonatal calves.     

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 1.0mm (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.     

Effects of feeding level and protein content of milk replacer on the performance of dairy herd replacements

It has been suggested that United Kingdom recommendations for feeding the neonatal calf (500 g milk replacer (MR)/day; 200-230 g CP/kg milk powder) are inadequate to sustain optimal growth rates in early life. The current study was undertaken with 153 high genetic merit, male and female Holstein-Friesian calves (PIN2000 = ￡48) born between September and March, with heifers reared and bred to calve at 24 months of age. Calves were allocated to one of four pre-weaning dietary treatments arranged in a 2 MR feeding level (5 v. 10 l/day) × 2 MR protein content (210 v. 270 g CP/kg dry matter (DM)) factorial design. MR was reconstituted at a rate of 120 g/l of water, throughout, and was offered via computerised automated milk feeders. Calves were introduced to pre-weaning diets at 5 days of age and weaned at day 56. During the first 56 days of life, calves offered 10 l MR/day had significantly higher liveweight gains (P < 0.001) than calves fed 5 l MR/day. No significant differences in liveweight gain were found between calves fed 210 g CP/kg DM MR and those fed 270 g CP/kg DM MR from birth to day 56. Differences in live weight and body size due to feeding level disappeared by day 90. Neither MR feeding level nor MR CP content affected age at first service or age at successful service, and with no milk production effects, the results indicate no post-weaning benefits of increased nutrition during the milk-feeding period in dairy heifers.     

Essential oils for dairy calves: effects on performance,scours, rumen fermentation and intestinal fauna

The first cause of death of dairy calves is often diarrhea which is mainly caused by pathogenic bacteria, which can result in excessive use of antibiotics. However, facing the increase concern by the industry and consumers, the use of antibiotics not only to control pathogens, but also to manipulate growth, has become a challenge. Alternative additives, such essential oils, have the potential to decrease antibiotic use, without reducing performance or increasing mortality of dairy calves. The objective of this study was to evaluate the use of a commercial blend of essential oils, incorporated into the calf starter and/or milk replacer to monitor the effect on overall calf performance, fecal scores and rumen fermentation parameters. A total of 30 Holstein calves received 6 l/day of a liquid diet, consisting of a commercial milk replacer containing 20% CP : 15% fat (EE). Calves had free choice access to water and calf starter. Weaning occurred at week 8, and calves were followed until the 10^th week of age. Calves were assigned to one of the three treatment groups in a randomized block design. Treatments: (1) control without essential oils supplementation (C); (2) essential oils blend in the milk replacer at 400 mg/kg (MR) and (3) essential oils blend in the milk replacer (200 mg/kg) and starter feed (200 mg/kg) (MRS). From the 2^nd week, calves were weighed and body measurements were taken, while concentrate intake and fecal scores were monitored daily. Blood samples were drawn weekly for determination of glucose and β-hydroxybutyrate. Fecal samples were collected weekly and analyzed for lactic acid bacteria and Enterobacteria; and ruminal fluid for determination of pH, short chain fatty acids, ammonia-N and counts of amylolytic and cellulolytic bacteria, and protozoa. Performance, fecal scores and intestines microorganisms were not affected by the essential oils supplementation. Ruminal and blood parameters were also not affected, with the exception the rumen ammonia-N concentration, with higher values when essential oils were supplemented in a combination of milk replacer and starter feed. Most of the evaluated parameters were affected by age of calves, mainly as a response to the increase in concentrate intake as animals’ aged. Essential oils are promising substitutes for antibiotics. However, the dose and routes of administration deserve further studies, allowing a better animal performance and health to be achieved.     

The Influence of Feeding and Oral Rehydration on the Bioavailability of Oxytetracycline in Calves

The influence of feeding on the bioavailability of oxytetracycline was studied in preruminant calves. Oxytetracycline was given in water as a drench to fasting calves or was mixed in the milk replacer. Compared to water the bioavailability was significantly reduced (53.5%) when oxytetracycline was mixed in the milk re-placer. A further reduction, 83.3 %, occurred when the calves were treated one hour post milk feeding. Also concentrate was found to reduce the bioavailability. Very high serum levels were recorded when the drug was given in an oral rehydration solution, pH 4.9, containing glycine. The values obtained when an alkaline (pH 8.3) solution without glycine was used did not differ from the levels recorded when oxytetracycline was given in water. It was suggested that the use of oxytetra-cyclines in feeds may be questioned because of their well-known complex forming ability.     

Feeding behavior, rumination, reticulo-ruminal fermentation and plasma volatile fatty acids, compared in goats and sheep; influence of the diet

Two-year old Alpine she-goats (n = 3) and Texel ewes (n = 3) were compared as to eating behaviour, rumination and volatile fatty acids (VFA) in rumen and blood. The animals were fed once daily with two different proportions (20 and 80%) of barley and hay. Dry matter intake was fixed at 48 g D.M/kg P0.75 per day. In similar feeding and environmental conditions, eating behaviour and rumination of goats and sheep did not differ much: the goats tended to eat faster and there were more rumination periods in the sheep. Latency time, mean duration of rumination periods, daily rumination time and circadian pattern of rumination did not differ significantly between the two species (fig. 1). With both diets we observed a higher VFA concentration and a lower acetate/propionate ratio in the rumen of the ewes; however, rumen pH was lower only in those eating the 80% barley ration (fig. 2). Blood VFA in the jugular vein did not differ between sheep and goats (fig. 3). The proportion of cereals and hay in the diets affected rumen fermentation and rumination pattern in both species. With a higher concentrate/roughage ratio, rumen and plasma VFA increased, while the pH and acetate/propionate ratio in the lumen juice, the number of rumination periods and daily rumination time decreased. When the animals were fed the 80% barley ration, there was practically no rumination in the first 9 h after the single meal. During this time, rumen pH was minimal and VFA levels in the rumen and blood were maximal.     

Effects of an artificial hay aroma and compound feed formulation on feed intake pattern,rumen function and milk production in lactating dairy cows

The Kempen system is a dairy feeding system in which diet is provided in the form of a compound feed (CF) and hay offered ad libitum. Ad libitum access to CF and hay allows cows in this system to achieve a high DM intake (DMI). Out of physiological concerns, the voluntary hay intake could be increased and the consumption pattern of CF could be manipulated to maintain proper rumen functioning and health. This study investigated the effects of an artificial hay aroma and CF formulation on feed intake pattern, rumen function and milk production in mid- to late-lactating dairy cows. Twenty Holstein–Friesian cows were assigned to four treatments in a 4 × 4 Latin square design. Diet consisted of CF and grass hay (GH), fed separately, and both offered ad libitum, although CF supply was restricted in maximum meal size and speed of supply by an electronic system. Treatments were the combination of two CF formulations – high in starch (CHS) and fibre (CHF); and two GH – untreated (UGH) and the same hay treated with an artificial aroma (TGH). Meal criteria were determined using three-population Gaussian–Gaussian–Weibull density functions. No GH × CF interaction effects on feed intake pattern characteristics were found. Total DMI and CF intake, but not GH intake, were greater (P < 0.01) in TGH treatment, and feed intake was not affected by type of CF. Total visits to feeders per day, visits to the GH feeder, visits to the CF feeder and CF eating time (all P < 0.01) were significantly greater in cows fed with TGH. Meal frequency, meal size and meal duration were unaffected by treatments. Cows fed CHF had a greater milk fat (P = 0.02), milk urea content (P < 0.01) and a greater milk fat yield (P < 0.01). Cows fed TGH had a greater milk lactose content and lactose yield (P < 0.05), and milk urea content (P < 0.01). Cows fed TGH had smaller molar proportions of acetic acid and greater molar proportions of propionic acid compared with UGH. In conclusion, treatment of GH with an artificial aroma increased CF intake and total DMI, but did not affect hay intake. Additionally, GH treatment increased the frequency of visits to both feeders, and affected rumen volatile fatty acid profile. Type of CF did not affect meal patterns, ruminal pH, nor fermentation profiles.     

Effects of an abrupt diet change from hay to concentrate on microbial numbers and physical environment in the cecum of the pony.

Microbial numbers, pH, fluid volume, and turnover rate in the pony cecum were measured during an abrupt change from an all-forage to an all-concentrate diet, both fed at maintenance energy levels. Concentrate feeding resulted in increased (P less than 0.01) numbers of total viable anaerobic bacteria. The numbers of organisms growing on selective starch medium increased (P less than 0.01) when concentrate was fed, while numbers on xylan and pectin media decreased (P less than 0.025). Seven days after the diet change to concentrate, the number of bacteria growing on lactate medium increased (P less than 0.01), followed by a gradual decline. Cellulolytic bacteria occurred in low numbers, ranging from 1.1 x 10(4) to 4.4 x 10(4) per g of cecal contents. Feeding all concentrate decreased both the number of genera (P less than 0.01) and total protozoan numbers (P less than 0.01) in the cecum. Minimum cecal pH values of 6.4 and 5.8 were obtained when forage and concentrate, respectively, were fed, with the minimum pH occurring 6 h postfeeding. Dry-matter percentage of cecal contents followed a diurnal pattern which was the inverse of the pH curve. During forage feeding, the cecum contained an average of 2.2 liters (1.6 to 3.4 liters), which turned over 3.9 times per day. When concentrate was fed, cecal volume averaged 3.9 liters (0.6 to 8.6 liters), with a mean liquid turnover of 4.2 times per day. Microbial numbers and pH changes in the pony cecum associated with an abrupt change in diet from hay to concentrate resembled those which occur in the rumen under similar feeding conditions.