Responses to condensed tannins of flowering sulla (Hedysarum coronarium L.) grazed by dairy sheep: Part 1: Effects on feeding behaviour, intake, diet digestibility and performance

The concentration of condensed tannins (CT) in sulla (Hedysarum coronarium L.) is moderate and overall regarded as beneficial. However, the intake of this forage can reduce diet digestibility, particularly during flowering phase. An experiment was run to assess the effect of CT on feeding behaviour, intake, diet digestibility and performance of dairy sheep rotationally grazing sulla at flowering phase. Twenty-four late-lactating sheep were blocked in two homogeneous groups and submitted to the following treatments: i) twice daily drenching with 200 g/day of a 50% w/v water solution of an anti-tannic substance, polyethylene glycol, group PEG; ii) twice daily drenching with 200 g/day of water, group CON (Control group). All the sheep rotationally grazed as a flock two sulla plots from April to June (8 weeks in total). Sward height, herbage mass, botanical and chemical composition of the herbage were measured at the beginning and the end of each grazing period. The feeding behaviour (3 sheep per group) was continuously monitored for 24 h in 6 weeks using the IGER behaviour recorders. Herbage DM intake (DMI), dietary DM digestibility (DMD) and apparent CP digestibility (CPD) were estimated on 8 sheep per group by the n-alkane method. On average, PEG group had longer total grazing (503 ± 12 vs 460 ± 12 min, P < 0.05) and eating time (425 ± 13 vs 391 ± 13 min, P < 0.07) than CON group. Moreover PEG group showed shorter inter-meal intervals (41 ± 3 vs 52 ± 3, min, P < 0.05) and higher number of daily meals than CT-exposed group (24 ± 1 vs 19 ± 1 min, P < 0.01). The herbage DMI was not affected by the treatment whereas DMD (74.60 ± 3.48 vs 58.30 ± 3.01%), and CPD (60.14 ± 4.83 vs 38.21 ± 4.83%) were both increased by PEG administration (P < 0.05) confirming the negative effect of sulla CT on these variables. Milk yield tended to be higher in PEG than CON (1331 ± 45 vs 1205 ± 59 ml, P < 0.11). Milk protein content was similar between groups while milk fat content was higher in CON than PEG ewes (6.61 ± 0.15 vs 6.11 ± 0.15%, P < 0.05), being the reverse true for milk urea (46.04 ± 1.27 vs 53.04 ± 0.76%, P < 0.001). To conclude, this experiment shows that when sulla is grazed at flowering as monoculture, dietary CT can exert negative effects on DM and CP apparent digestibility, in this study partially counterbalanced by a better metabolic utilisation of the nutrients up-taken.     

Alfalfa as a supplement of dried cornstalk diets: Associative effects on intake, digestibility, nitrogen metabolisation, rumen environment and hematological parameters in sheep

The aim of the current study was to investigate the associative effects of a cornstalk-based diet supplemented with alfalfa (Medicago sativa) hay on intake, digestibility, nitrogen (N) metabolisation, rumen environment and hematological parameters in Xiaoweihan sheep. We also investigated the optimal range of alfalfa hay to achieve positive associative effects and avoid negative effects. Xiaoweihan sheep (n = 5; fitted with rumen T-cannula) were fed five cornstalk-based diets in a 5 × 5 Latin square design. Diets contained 0, 50, 150, 300, 450 g alfalfa, and were supplemented with 100 g concentrate, respectively. Our results suggested that supplementation of 300 g alfalfa hay reduced (P < 0.05) cornstalk intake, but significantly increased dry matter (DM) intake (P < 0.05). Additionally, DM digestibility of 150 g alfalfa hay supplementation was slightly higher than that noted in other diets. Metabolism studies showed 50–150 g alfalfa hay supplementation had a positive associative effect (P < 0.05) on N utilization, with the greatest benefit noted with 150 g per day (P < 0.05) compared to unsupplemented diets. Alfalfa supplementation (50–450 g per day) resulted in an elevated trend of ammonia nitrogen (NH₃–N) with 50 or 150 g of alfalfa hay more likely to promote sheep rumen environment, with a noticeable increase (P < 0.05) in serum urea nitrogen (UREAN) concentrations observed with 300 g alfalfa hay per day. Our data suggested that the optimal range to achieve beneficial effects and avoid negative effects was 150–300 g per day for cornstalk-based diets for sheep.     

The effect of grain species, processing and time of feeding on the efficiency of feed utilization and microbial protein synthesis in sheep

This study investigated the effect of cereal grain species (sorghum, wheat, oats and barley), extent of processing (cracked barley, finely ground barley, and wet whole barley) and time of feeding (barley grain mixed with ryegrass hay or fed 2 h before hay was fed), on whole tract dry matter digestibility (WTDMD), and microbial protein synthesis (MPS), as a supplement to ryegrass hay when fed to rumen-cannulated sheep.Expected dry matter digestibility (EDMD) in mixtures of cereal grain and ryegrass hay was calculated by interpolation between in vitro dry matter digestibility (DMD) of each grain and the ryegrass hay. These were compared with measured actual WTDMD to detect positive or negative associative effects. Among grain species, the percentage difference in digestibility between actual WTDMD and EDMD was negative at − 6.6% units for wheat but positive at + 2.3%, + 4.3% and + 5.7% units for sorghum, oats, cracked or finely ground barley, respectively.As expected, the supplementation of sheep fed ryegrass hay with different sources of carbohydrates increased urinary allantoin output (as an indicator of MPS) when compared to sheep fed ryegrass hay alone. The concentration of urinary allantoin was significantly higher in sheep supplemented with sorghum (1916 mg/sheep/day) than wheat, oats or cracked barley ([mean ± S.E.M.] 1451 ± 24 mg/sheep/day) grain. There was a significantly higher urinary allantoin concentration in sheep fed cracked barley compared to finely ground barley or wet whole barley (1479 vs. 1095 vs. 1031 mg/sheep/day, respectively). There was no significant (P > 0.05) difference in urinary allantoin output, expressed as output/kg DM intake, when cracked barley was mixed and fed with the hay or fed 2 h before hay. However, in terms of total output of allantoin this was significantly higher (P < 0.05) (1479 vs. 1209 mg/sheep/day).In sacco degradability characteristics of organic matter and nitrogen for sorghum, oats, wheat, barley at different levels of processing and for ryegrass hay were also measured in the rumen of cannulated sheep.Among grain species, wheat had the highest effective organic matter degradability in the rumen (78.1%) while sorghum had the lowest. The effective degradability of protein of finely ground barley in the rumen was found to be higher than cracked barley or wet whole barley.Wheat grain, being highly degradable in the rumen, had a negative effect on WTDMD. In contrast, sorghum grain, being more slowly degradable in the rumen, would be expected to provide a substantially increased supply of energy to microbes over time in the rumen for MPS.Both cracked barley and finely ground barley also had a positive associative effect on WTDMD when fed with ryegrass increasing it by 5.7% units. The MPS was significantly higher (P < 0.05) in sheep fed cracked barley compared to finely ground barley or wet whole barley. This supports the hypothesis that slowly degrading carbohydrate sources synchronise more closely with available N from degradation of forage in the rumen.     

Responses to condensed tannins of flowering sulla (Hedysarum coronarium L.) grazed by dairy sheep: Part 2: Effects on milk fatty acid profile

A grazing experiment was undertaken to evaluate the effect of PEG supplementation on the fatty acid composition of milk from Sarda sheep grazing sulla. Twenty-four late-lactating sheep (12 per group), were paired and split into two groups: group control (CON), dosed daily with a quenching gun with 200 ml of water, and group PEG, dosed with 200 ml of a 50/50 w/v water solution of PEG. The sheep grazed two 0.8 ha plots of sulla under a rotational grazing scheme.The contents of c-9, t-11 CLA and t-11 C18:1 in milk fat were on average 40% higher (P < 0.01) in the PEG group than in the CON group. This can be explained by the higher biohydrogenation activity of ruminal bacteria in the PEG group, due to the partial inactivation of the tannins. Odd-branched chain fatty acids (OBCFA) were higher in PEG than in the control group (+ 20%; P < 0.01) and this confirms the hypothesis that tannin in sulla reduced ruminal microbial activity. Both linoleic (C18:2 c-9 c-12) and linolenic (C18:3 c-9 c-12 c-15) fatty acids were lower (P < 0.05) in milk from PEG, than in the CON-group (− 12% and − 30% for linoleic and linolenic acids, respectively). The mitigating effect on tannins of PEG increased the ratio of ω6/ω3 by 24%; (P < 0.01) and total trans FA content in milk by 20% (P < 0.01). In conclusion, condensed tannins in sulla at flowering are conducive to lower c-9, t-11 CLA and t-11 C18:1 but also lower total trans FA, ω6/ω3 ratio and higher linoleic and linolenic acid.     

Efficacy of Ivermectin Delivered via a Controlled‐Release Capsule against Small Lungworms (Protostrongylidae) in Sheep

To evaluate the efficacy of an ivermectin controlled‐release capsule (CRC), which delivers 1.6 mg ivermectin per day intraruminally for 100 days to sheep weighing 40–80 kg (IVOMEC^® Maximizer^TMCR Capsule for adult sheep, Merial), against small lungworms two studies with 48 naturally infected adult female Merino Landrace sheep were conducted. The sheep were allocated by restricted randomization based on bodyweight to untreated controls or received an ivermectin CRC. Eight sheep per group were necropsied 35, 70 or 105 days post‐treatment. Lungworms were recovered by dissection or peptic digestion of the lungs. Baermann/Wetzel technique was used for faecal lungworm larval counts at weekly intervals. The efficacy of treatment was 100% against Dictyocaulus filaria and Protostrongylus rufescens (P < 0.05) at each necropsy day. The efficacy against Protostrongylus brevispiculum, Cystocaulus ocreatus and Neostrongylus linearis increased from 35 to 105 days after administration of the CRC and was found to be 100% (P < 0.01), 96.6% (P < 0.01) or 99% (P < 0.01), respectively, at 105 days post‐treatment. The reductions of Muellerius capillaris counts varied and were 96.2% (P < 0.05) at 70 days post‐treatment and 44.6% (P > 0.1) at 105 days post‐treatment. Faecal lungworm larvae disappeared nearly completely from at least 3 weeks after the ivermectin CRC administration for all protostrongylid species including M. capillaris so that pasture infectivity will be subsequently significantly reduced.     

Energy balance, milk production and reproduction in grazing crossbred cows in the tropics with and without cereal supplementation

The aim of this work was to study the effect of parity order and reproductive management systems on rabbit production performance. A total of 73 rabbit does (I group) were submitted to a 35-day intensive rhythm [artificial insemination (AI) on day 4 post-partum (pp) and weaning at 25 days of lactation], and 108 rabbit does (SI group) were submitted to a 42-day semi-intensive rhythm (AI on day 11 pp and weaning at 35 days of lactation) during 9 months. Primiparous does had the lowest live body weight at parturition (P < 0.0001) and at 21 days of lactation (P < 0.0001). They also had lower milk production (P < 0.0001) than does with later parities. I group animals needed a higher number of AI than SI group to become pregnant (1.70 ± 0.03 vs. 1.39 ± 0.03; P < 0.0001: especially after the third). Prolificacy was not affected by the management system. Parturition interval (PI) was longer than expected in both groups [56.0 ± 1.4 and 50.9 ± 1.38 days in I and SI groups, respectively (P < 0.05)]. Mean productivity, estimated as number of weaned rabbits per female and year, was 12 kits higher in rabbit does of the SI group (P < 0.05). From the third parturition onward, an increase in live body weight of kits at different ages was observed. At 21 (P < 0.05) and 25 days of age (P < 0.01), kits from the I group rabbit does weighed more than those from the SI group; however, the latter showed a higher weight at 35 (P < 0.05) and 60 days of age (P < 0.05). Rabbit does with two or three parturitions had higher litter size at 21 and 25 days of age (P < 0.0001 and P < 0.001, respectively). Kit mortality between 21 and 25 days of age and between 35 and 60 days of age was not affected by treatments but was higher in the I group between 25 and 35 days (18.2 vs. 5.03% in the I and SI groups, respectively; P < 0.0001) and as age of does increased (P < 0.05). In light of these results, we could conclude that long term doe reproductive performance is negatively affected and litter viability decreased when using intensive compared to a semi-intensive reproductive management.     

Growth and carcass characteristics of lambs in relation to plasma IGF-I and some histological traits of Longissimus lumbarum and Biceps femoris as affected by breed and age at slaughter

Ten male lambs of each of Rahmani (R) and Ossimi (O) were used to study the growth and carcass characteristics within their first year of age (360 days). After suckling period (4 months), lambs were fed on the regular ration. During the course of the experiment, body weight (BW) was recorded monthly accompanied by blood sampling to determine IGF-I. Four lambs from each breed were slaughtered at 270 and 360 days of age, and Longissimus lumbarum (L. lumbarum) at the 9th, 10th and 11th ribs and Biceps femoris (B. femoris) muscles were separated to be used for chemical analysis and histological study.Breed had no effect on the growth curve of the two studied breeds. Chemical analysis indicated that (O) had higher fat (0.9%, P < 0.0001) and lower (0.3%, P < 0.01) moisture compared to (R), with no difference in protein and ash contents. The concentration of IGF-I was almost similar in both breeds up to day 270 of age, and then it was higher in (R). Number of fibers per bundle was higher (P < 0.05) in (O) than in (R) by 6.1%, while, the other histological traits were similar in the two studied breeds.Chemical analysis indicated that lambs slaughtered at 360 days of age had lower (0.7%, P < 0.0006) moisture and higher fat (17.3%, P < 0.0001) compared to day 270. Up to day 270 of age, IGF-I concentration was < 500 ng/ml before increasing to > 500 ng/ml up to the end of the experiment. No effect of age was observed on the studied histological traits.L. lumbarum muscle contained higher protein (4.2%, P < 0.0001), fat (104%, P < 0.0001) and ash (10%, P < 0.001), while moisture was less (5.6%, P < 0.0001) compared to B. femoris muscle. B. femoris muscle was higher (P < 0.0001) in number and diameter of fibers, bundle and stroma sectional areas relative to L. lumbarum by 38.2, 78.8, 53.2 and 23.8%, respectively.     

Effects of transportation during the hot season and low voltage electrical stimulation on histochemical and meat quality characteristics of sheep longissimus muscle

The effect of transportation during the hot season (42 °C) and low voltage electrical stimulation on physiological, histochemical and meat quality characteristics of Omani sheep was studied. Forty intact male sheep were divided into two equal groups: 3 h transported or non-transported. The non-transported group remained in holding pens for 48 h prior to slaughter, while the transported group was transported 300 km (approximately 3 h) in an open truck under solar radiation on the day of slaughter. Blood samples were collected from the animals before loading and prior to slaughter. Fifty percent of the carcasses from each group were randomly assigned to low voltage (90 V) at 20 min postmortem. Temperature and pH decline of the left longissimus thoracis muscle were monitored. Ultimate pH, WB-shear force, sarcomere length, myofibrillar fragmentation index (MFI), expressed juice, cooking loss and color L, a, b were measured on samples from both sides muscles collected at 24 h postmortem at 3–4 °C. The transported sheep had significantly higher plasma cortisol (P < 0.01), adrenaline, nor-adrenaline and dopamine concentrations (P < 0.05) than non-stimulated animals. Electrical stimulation resulted in a significantly (P < 0.05) more rapid pH fall in muscle during the first 12 h after slaughter. Muscles from electrically-stimulated carcasses had significantly (P < 0.05) lower pH values, longer sarcomere length, lower shear force value, higher expressed juice, MFI and lighter L than those from non-stimulated ones. The muscle samples from the transported sheep had significantly (P < 0.05) smaller and lower proportion of Types I and IIA fibers than those from the non-transported group. This study indicated that pre-slaughter transport at high ambient temperatures can cause noticeable changes in physiological and muscle metabolism responses in sheep. Electrical stimulation improved meat quality characteristics, which indicate that meat quality of transported sheep can be improved by electrical stimulation.     

The supplementary value of different parts of enset (Ensete ventricosum) to sheep fed wheat straw and Desmodium intortum hay

A study which included growth and digestibility experiments was conducted to evaluate the feeding value of a) enset pseudostem, b) enset corm or c) enset mixture (containing equal amounts of pseudostem, corm and enset leaf on a DM basis) as a supplement to a basal diet of wheat straw fed ad libitum and restricted amounts of Desmodium intortum (Desmodium) hay to sheep. During the 71-day growth experiment, 18 one-year-old male sheep of indigenous breed with mean body weight (BW) of 20.2 (± 0.43) kg were randomly assigned to the three treatments. In the digestibility experiment, three male sheep with mean BW of 19.5 (± 1.06) kg were assigned to each treatment. Sheep supplemented with enset mixture consumed more (P < 0.001) wheat straw DM (335 g/day) than those supplemented with pseudostem (295 g/day). No differences were found in total dry matter (DM) and organic matter (OM) intake between diets supplemented with pseudostem, corm and enset mixture. Total nitrogen (N) intake (g/day) was higher (P = 0.0073) in sheep fed the diet with enset mixture (12.2) followed by corm (11.3) and pseudostem (10.7). The apparent digestibility of DM was higher (P < 0.001) in pseudostem (0.53) followed by corm (0.46) and enset mixture (0.41) supplemented sheep. Organic matter, neutral detergent fiber and N digestibility were similar among treatments. The amount of N lost in urine and faeces and the N-retention was similar among treatments. There were no differences in gain/day in sheep fed diets with pseudostem (29.3 g), corm (27.0 g) and enset mixture (36.5 g). It is concluded that supplementation of a wheat straw/Desmodium diet with enset fractions could be used equally at least to maintain body weight during the dry season.     

Resistance of Santa Ines and crossbred ewes to naturally acquired gastrointestinal nematode infections

This trial was carried out in Piracicaba, São Paulo State, Brazil, to comparatively evaluate the degree of resistance to naturally acquired gastrointestinal nematode infections in sheep of the following genetic groups: purebred Santa Ines (SI), SI crossbred with Dorper (DO × SI), Ile de France (IF × SI), Suffolk (SU × SI), and Texel (TE × SI). Fifteen ewes from each group were raised indoors until 12 months of age. At this age, they were moved to pasture that was naturally contaminated by nematode infective larvae and were evaluated from December to May, 2007. Rainfall ranged from 267 mm in January to 37 mm in April. Maximum and minimum mean temperatures ranged from 32.5 °C to 19.0 °C in March and from 25.9 °C to 12.8 °C in May. There was an increase in the mean number of eggs per gram of feces (EPG) after animals were placed on pasture with significant difference between the SI (80 EPG) and IF × SI (347 EPG) groups in January; and the DO × SI (386 EPG) and TE × SI (258 EPG) groups in May. The highest mean fecal egg count (FEC), 2073 EPG, was recorded for the TE × SI group in February. All groups showed a progressive reduction in body weight throughout the experiment of 12.0% (TE × SI) to 15.9% (SU × SI). In general, the animals with the highest FEC presented the lowest packed cell volumes (PCV); the highest correlation coefficient between FEC × PCV occurred in the SU × SI sheep in January (r = −0.70; P < 0.01). Similarly, there was an inverse relationship between FEC and blood eosinophil values, with the highest correlation coefficient in the TE × SI sheep in February (r = −0.64; P < 0.05). Immunoglobulin G (IgG) levels against Haemonchus contortus antigens increased in all groups as a result of the exposure to parasites and remained relatively constant until the end of the study, with the exceptions of SU × SI and TE × SI, which showed a rise in IgG levels during the last sampling that coincided with a reduction in mean FEC. In conclusion, crossbreeding Santa Ines sheep with any of the breeds evaluated can result in a production increase and the maintenance of a satisfactory degree of infection resistance, especially against H. contortus and Trichostrongylus colubriformis, the major nematodes detected in this flock.     

Effect of energy restriction in interaction with genotype on the performance of growing rabbits: II. Carcass traits and meat quality

In this experiment the effect of digestible energy (DE) restriction on carcass traits and meat quality of rabbits selected divergently for body fat content was studied. Using a 2 × 3 factorial arrangement, Pannon White rabbits selected for high (HFAT) or low (LFAT) total body fat content were fed isocaloric diets between 4 and 12 weeks of age. Energy restriction was achieved by reducing the daily feed intake by 10% (M) and 20% (L) compared to the ad libitum fed group (H). Proportional to the reduction of feed intake the nutrient density of diets M and L was increased. Thus, the DE intake was reduced while the nutrient intake remained stable among the 3 dietary groups. Effect of genetic group on carcass traits and on meat quality parameters was less marked than DE restriction. Selection for high body fat content improved the dressing out percentage (58.3 and 57.3% in HFAT and LFAT respectively; P < 0.01), and reduced the percentage of the full gastrointestinal tract to slaughter weight (13.7 and 14.3% in HFAT and LFAT respectively; P < 0.05). Reduction of DE intake decreased the body weight and the weight of the chilled and reference carcass (P < 0.001), while it had no effect on dressing out percentage. In group H the percentage of fore part to reference carcass was higher (29.7 vs 29.0%; P < 0.01) while that of the hind part was lower than in group L (37.0 vs 38.2%; P < 0.001). The Longissimus lumborum meat from HFAT rabbits exhibited a lower content of moisture (76.1 and 76.5% in HFAT and LFAT respectively; P < 0.01) as well as lower L (53.5 and 54.4 in HFAT and LFAT respectively; P < 0.05) and b (0.42 and 0.81 in HFAT and LFAT respectively; P < 0.05) colour values. When compared with ad libitum fed rabbits, those restricted at 20% (L) exhibited a higher content of moisture (76.9 vs 75.8%; P < 0.01), as well as higher pHu (5.87 vs 5.73; P < 0.01) associated with lower cooking loss (17.8 vs 19.1%; P < 0.05). L rabbits also produced lower values of redness (a, 2.21 vs 3.35; P < 0.01) and yellowness (b, 0.23 vs 0.91; P < 0.01). No effect of the divergent selection for body fat content on the total lipid percentage and on most of the fatty acids in the meat of the hind leg was found. DE restriction resulted in lower SFA (L: 32.1 vs H: 35.8%; P < 0.01) and MUFA (L: 21.0 vs H: 28.6; P < 0.01) but higher PUFA contents (L: 45.5 vs H: 34.9%; P < 0.01) in the hind leg meat.     

Serum profile of metabolites and hormones in obese (Iberian) and lean (Landrace) growing gilts fed balanced or lysine deficient diets

Serum hormones and metabolites of lean and obese gilts were determined. Fifteen Iberian and fifteen Landrace gilts, of approximately 20 kg body weight, were fed isoenergetic (13.6 kJ ME/g DM, semisynthetic diets either with equilibrated amino acid profile at two crude protein (CP) levels (12% (0.81% lysine (Lys)) and 16% CP (1.08% Lys) as-fed basis) or lysine deficient (12% (0.30% Lys) or 16% CP (0.36% Lys) as-fed basis for Iberian and Landrace, respectively). Lysine deficient diets were offered only at the optimal protein level for maximum protein accretion for each breed. Each dietary treatment was assayed in 5 animals. Gilts were allocated in metabolic cages at 21 ± 1.5 °C with free access to water and fed four times daily at 90% ad libitum during 10 days. On day 11th blood samples were taken 5–5.5 h postprandial and serum obtained and frozen at − 20 °C. Growth hormone (GH), insulin like growth factor I (IGF-1), insulin, leptin, glucose, urea, creatinine, cholesterol and triglycerides were determined. Landrace gilts had higher serum glucose (P < 0.05) and creatinine (P < 0.001) than Iberian while no differences (P = 0.122–0.494) were found for the rest of the biochemical variables. Higher serum levels of insulin, IGF-1 and leptin (60, P < 0.05; 79, P < 0.05 and 189%, P < 0.001, respectively) and no differences in GH (P = 0.512) were encountered in Iberian gilts compared to Landrace. Dietary crude protein did not alter the serum hormonal profile (P = 0.110–0.454). Serum cholesterol (total, P < 0.01; HDL, P < 0.05; LDL, P < 0.05) decreased and triglycerides and urea increased (P < 0.05 and P < 0.001, respectively) as dietary crude protein increased. When lysine deficient diets were used, serum glucose decreased (P < 0.05) and urea increased (P < 0.001) compared to equilibrated diets. Serum insulin (P = 0.052), IGF-1 (P < 0.05) and leptin (P = 0.051) concentration decreased when lysine deficient diets were fed to the animals while GH remained unaffected (P = 0.214).These data suggest that Iberian and Landrace growing gilts have distinct hormone and metabolite serum profiles which are altered by a severe dietary lysine deficiency.     

Effect of dietary inclusion of benzoic acid on mineral balance in growing pigs

The objective of this study was to determine the effect of dietary inclusion of benzoic acid on utilization of the macrominerals Ca, P, Mg, K, Na, and Cl in growing pigs. Eighteen barrows, initial BW of 28 ± 1.7 kg, were assigned to 3 diets: a basal diet based on barley, wheat, soybean meal, corn, and field pea and formulated to contain 9.31 MJ NE kg^− 1 and 8.84 g^− 1 kg standardized ileal digestible lysine, or the basal diet containing 10 or 20 g kg^− 1 benzoic acid by replacing tapioca starch. The pigs were fed the experimental diets a rate of 2.7 times the maintenance requirement for ME for 21 days. Faeces and urine were collected quantitatively from days 11 to 21, and blood and plasma was collected on days 1, 10, and 21. On day 21, the pigs were killed and the left femur was removed. Benzoic acid linearly decreased (P = 0.001) the urine pH from 7.32 to 5.32, and quadratically increased (P < 0.05) blood pH on day 21. Benzoic acid linearly increased (P < 0.05) the apparent total tract digestibility (ATTD) of Ca, P, and Na from 65 to 72%, 46 to 55%, and 78 to 90%, respectively, linearly decreased (P < 0.05) the ATTD of Cl from 94 to 93%, and did not affect the ATTD of Mg and K. Benzoic acid linearly increased (P < 0.05) the retention of Ca, P, and K from 58 to 67%, 46 to 54%, and 31 to 38%, respectively, linearly decreased (P < 0.05) the retention of Na and Cl from 57 to 48% and 75 to 44%, respectively, and did not affect retention of Mg. On day 21, benzoic acid linearly increased (P = 0.001) plasma P and quadratically increased (P < 0.05) plasma K or tended to increase (P = 0.05) plasma Na. Benzoic acid linearly reduced (P < 0.05) the concentration of ash in femur but not the amount of ash, reduced (P < 0.05) the concentration of Ca and Cl in femur ash, and linearly increased (P < 0.05) the concentration of P in femur ash. In summary, benzoic acid increased the utilization of dietary Ca, P, and K, did not affect the utilization of dietary Mg, and reduced the utilization of dietary Na and Cl. During swine feed formulation, effects of benzoic acid on macromineral utilization should be considered to ensure that macromineral requirements are met and not exceeded following benzoic acid supplementation.     

Effects of replacing grass silage harvested at two maturity stages with maize silage in the ration upon the intake, digestibility and N retention in wether sheep

The objective of this experiment was to study the effects of interactions between medium quality grass silage (GS1) and maize silage (MS) as well as between low-quality grass silage (GS2) and MS on ad libitum intake, digestibility and N retention in wether sheep. Two grass silages (GS1 and GS2) were ensiled in round bales, without additives, from the primary growth of orchard grass (Dactylis glomerata L.) harvested at two different maturity stages. The study consisted of seven feeding treatments incorporating GS1, GS2 and MS fed alone and forage mixtures of GS1 and MS as well as GS2 and MS (67:33% and 33:67%, respectively, DM (dry matter) basis).Delayed harvesting lowered (P < 0.05) the crude protein (CP) concentration in GS2 compared to GS1. The DM content (g kg^− 1 fresh sample) and starch concentration (g kg^− 1 DM) of MS were 264 and 211, respectively.Inclusion of MS in the GS1-based ration had positive linear effects on CP and starch digestibility (P < 0.05 and P < 0.01, respectively) and N intake (P < 0.01) while a negative effect on neutral detergent fibre (NDF) and acid detergent fibre (ADF) digestibility (P < 0.05 and P < 0.01, respectively). A positive associative response of GS1 and MS was observed for DM ad libitum intake (g kg^− 1 M^0.75 day^− 1) (quadratic, P < 0.05), CP digestibility (quadratic, P < 0.01), N intake (quadratic, P < 0.01) and N balance (quadratic, P < 0.05). Inclusion of MS into the GS2-based ration had a positive linear effect on the ration fresh matter ad libitum intake (kg day^− 1 and g kg^− 1 M^0.75 day^− 1) (P < 0.01 and P < 0.001, respectively), NDF ad libitum intake (kg day^− 1 and g kg^− 1 M^0.75 day^− 1) (P < 0.01), digestibility of DM (P < 0.01), organic matter (OM) (P < 0.01), ADF (P < 0.05), starch (P < 0.001), digestibility of OM in DM (D-value) (P < 0.001), and N intake (P < 0.01). Positive associative effects of GS2 and MS were observed on all the intake and digestibility parameters measured, N intake (quadratic, P < 0.001) and N balance (quadratic, P < 0.05). It was concluded that, as expected, a positive associative response of GS2 and MS was recorded for all the measured parameters while that of GS1 and MS for a limited number of parameters, probably due to lower quality of MS (lower starch concentration) than required for improved utilization of the GS1-based ration.     

Molecular screening and risk factors of enterotoxigenic Escherichia coli and Salmonella spp. in diarrheic neonatal calves in Egypt

The aim of the present study was to carry out molecular epidemiological investigation on enterotoxigenic Escherichia coli (ETEC) K99 and Salmonella spp. in diarrheic neonatal calves. Fecal samples were obtained from 220 diarrheic calves at 9 farms related to four governorates in central and northern Egypt. E. coli and Salmonella spp. isolates were examined for E. coli K99 and Salmonella spp. using PCR. ETEC K99 was recovered from 20 (10.36 %) out of 193 isolates, whereas Salmonella spp. was recovered from nine calves (4.09%).Multivariable logistic regression was used to evaluate the risk factors associated with both infections. ETEC K99 was significantly affected by age (P < 0.01; OR: 1.812; CI 95%: 0.566–1.769), colostrum feeding practice (P < 0.01; OR: 5.525; CI 95%: 2.025–15.076), rotavirus infection (P < 0.001; OR: 2.220; CI 95%: 0.273–1.251), vaccination of pregnant dams with combined vaccine against rotavirus, coronavirus and E. coli (K99) (P < 0.001; OR: 4.753; CI 95%: 2.124–10.641), and vitamin E and selenium administration to the pregnant dam (P < 0.01; OR: 3.933; CI 95%: 0.703–1.248).Infection with Salmonella spp. was found to be significantly affected by the animal age (P < 0.05; OR: 0.376; CI 95%: 0.511–1.369), Hygiene (P < 0.05; OR: 0.628; CI 95%: 1.729–5.612), and region (P < 0. 01; OR: 0.970; CI 95%: 0.841–1.624).The results of the present study indicate the importance of PCR as rapid, effective and reliable tool for screening of ETEC and Salmonella spp. when confronted with cases of undifferentiated calf diarrhea. Moreover, identification of the risk factors associated with the spreading of bacteria causing diarrhea may be helpful for construction of suitable methods for prevention and control.     

Influence of dietary condensed tannins from sericea lespedeza on bacterial loads in gastrointestinal tracts of meat goats

This research assessed the potential use of a low input forage containing a high amount of condensed tannins (CT) to reduce foodborne pathogens prior to slaughter of meat goats. In a completely randomized design, twenty Kiko × Spanish intact male kids (BW = 19.2 ± 0.74 kg) were fed ground sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours) G. Don; 2 pens], a high-CT legume, or bermudagrass hay [BG; Cynodon dactyon (L.) Pers.; 2 pens], at 75% of daily intake with a corn-based supplement (25% of intake) for 14 weeks (n = 10 goats/treatment). At the end of the feeding trial, the animals were slaughtered using standard procedures. Immediately after evisceration, rumen and rectal samples were collected to assess bacterial loads and volatile fatty acids in the rumen. Concentrations of rumen volatile fatty acids were significantly different between dietary treatments. Goats fed SL hay had higher (P < 0.05) contents of butyric (8.66 vs 7.16 mM), isobutyric (1.94 vs 1.44 mM), isovaleric (3.03 vs 2.13 mM), and valeric (1.43 vs 1.07 mM) acids than those fed BG hay; however, the content of acetic acid (78.6 vs 64.4 mM) was higher (P < 0.05) in the BG-fed groups than in SL-fed groups. Escherichia coli (2.33 vs 1.13 log₁₀ CFU/g) counts of rumen contents were higher (P < 0.05) in the SL-fed group compared with the BG-fed group. However, E. coli counts in feces were not different (P > 0.05) between dietary treatments. The high-CT influenced (P < 0.05) total plate counts in the feces; and the total plate counts in feces of SL- and BG-fed goats were 4.95 and 6.57 log₁₀ CFU/g, respectively. The results indicated that high CT in the diet might influence rumen volatile fatty acid composition, but might not reduce the bacterial loads in gastrointestinal tracts of meat goats.     

Intake, performance and carcass characteristics of beef cattle offered diets based on whole-crop wheat or forage maize relative to grass silage or ad libitum concentrates

Seventy beef steers, mean initial live-weight 424 (S.D. 33.0) kg, were blocked by live-weight and breed and allocated to one of 5 dietary treatments in a randomised complete block design. Treatments, including supplementation with 3 kg concentrates/head/day, were grass silage (GS), maize silage (MS), fermented whole-crop wheat (FWCW), urea-treated, processed whole-crop wheat (UPWCW), and ad libitum concentrates supplemented with 5 kg grass silage/head/day (ALC). The grain in urea-treated, processed whole-crop wheat (WCW) was cracked and the crop ensiled with a urea plus urease-based additive. The mean dry matter (DM) of the grass silage, maize silage, fermented WCW and urea-treated, processed WCW was 174, 315, 404 and 716 g/kg, respectively. Total DM intake and carcass growth were lowest for GS (P < 0.001). Relative to ALC, feed conversion efficiency (FCE) (P < 0.05), live-weight gain (P < 0.05), carcass-weight gain (P < 0.01) and kill-out rate (P < 0.05) were lower for GS, FWCW and UPWCW. The MS had a better FCE than the UPWCW (P < 0.001) or the FWCW (P < 0.05). Plasma urea concentration was lowest for MS and highest for UPWCW (P < 0.001). Animals offered the GS treatment had the most yellow fat (higher (P < 0.05) ‘b’ value) and those offered UPWCW had the whitest fat (lower (P < 0.01) ‘b’ value). It is concluded that MS, FWCW and UPWCW supported superior levels of growth by cattle compared to GS (in vitro DM digestibility 674 g/kg). There was no animal productivity advantage with UPWCW compared to FWCW.     

Gut ecology, feed digestion and performance in weaned piglets fed liquid diets

Gut environment and microflora, digestibility, and performance were studied in weaned piglets in Central Vietnam fed a dry control diet (CO), a naturally fermented liquid diet (FE), and a liquid diet with inclusion of rice distiller's residue (RDR). Digesta samples were collected at the start (day 0) and at the end of experiment (day 42). Diet FE had a lower pH than diet RDR, contained more organic acids, had the lowest counts of E. coli and total coliforms (P < 0.05), and the highest counts of lactic acid bacteria (LAB) (P < 0.05). Piglets fed diets FE and RDR had lower pH (P < 0.05), and higher concentrations of organic acids in the stomach, ileum and mid-colon (P < 0.05) than piglets fed diet CO. Counts of LAB in stomach and ileum were higher in animals fed diets FE and RDR than CO (P < 0.05), while the number of E. coli and total coliforms along the gastrointestinal tract was reduced. The ileal digestibility of crude protein and organic matter was improved in piglets fed diet RDR (P < 0.05) compared with piglets fed diet CO. Piglets fed diet RDR had a higher weight gain (P < 0.05) and a better feed utilization (P < 0.05) than piglets fed the other diets. The present findings support the contention that fermented diets and/or fermented feedstuffs can be used for dietary manipulation to improve gut health and animal performance.     

Diverse production system and social status effects on pig immunity and behavior

Pig performance, immunity, and behavior may be influenced by production system and social status. A conventional indoor housing system was compared with an outdoor system to determine the effects of diverse production systems on pig performance, behavior, and immunity. At 21 days of age, weight matched pigs reared in a conventional indoor or an outdoor production system were weaned and randomly selected for use in the present study. Six replicate pens were evaluated per treatment, with two littermate female pigs in each pen. Social status was determined at 7 weeks of age by a feed competition test. Pig behavior was recorded for 24 h using a scan sample technique. At 9 weeks of age, blood samples were taken from indoor- and outdoor-reared pigs and immune assays performed. Both indoor- and outdoor-reared pigs were given a sheep red blood cell (SRBC) challenge at 6 and 8 weeks of age, and antibody titers to SRBC were measured at 6, 7, and 9 weeks of age. Performance data were recorded throughout the study period. Body weight and average daily gain were not influenced by the production system in which the pig was reared. The production system effected standing, lying, drinking, and oral/nasal/facial behaviors. The production system influenced the expression of certain behaviors depending on the time of day. Immune and blood measures were affected by production system. The percentage of phagocytosis was greater (P ≤ 0.05) and antibody titers to SRBC challenge tended to be greater (P = 0.066) among outdoor-reared pigs compared with indoor-reared pigs. Outdoor reared pigs had higher hemoglobin concentrations (P < 0.005), percentage of hematocrit (P < 0.005), mean corpuscular volume (P < 0.005), and mean corpuscular hemoglobin (P < 0.005) compared with indoor-reared pigs. Furthermore, dominance order influenced the immune system. Dominant pigs had greater phytohemagglutinin stimulated lymphocyte proliferation (P < 0.01) and baseline antibody titers to sheep red blood cells (P < 0.05) compared with submissive pigs. In conclusion, in the present study body weight and average daily gain were similar among diverse production systems. However, pig behavior and immune system were significantly influenced by the production system. Dominance order influenced the immune system regardless of the production system.     

Supplementation of dairy cows with a fish oil containing supplement and sunflower oil to increase the CLA content of milk produced at pasture

It has been shown that the cis 9, trans 11 isomer of conjugated linoleic acid (CLA) can be increased in milk by supplementation with fish oil and vegetable oils. Feeding a high level of oil, however, can impact negatively on gross milk composition. The principal aim of this study was to determine if relatively low levels of fish oil or sunflower oil, either alone or in combination, offered to dairy cows on pasture would increase the C18:2 cis 9, trans 11 CLA concentration in milk. Forty autumn-calved cows on a diet of grazed grass were assigned to 4 supplementation treatments: (i) No supplement (P), (ii) 255 g/day of sunflower oil (SO), (iii) 255 g/day of sunflower oil + 52.5 g/day of fish oil (SOFO), and (iv) 105 g/day of fish oil (FO). The fish oil was supplied in a proprietary product called Omega-3 Supplement which is a mixture of marine oils and an extracted oilseed meal and contains 500 g/kg of oil. The oils were fed in a concentrate mixture, which was offered at a rate of 3.0 kg/cow per day. The production of the cows was measured for 54 days and the milk fatty acid composition was determined on day 0 (immediately before the supplements were introduced) and on days 14, 28 and 42 after the treatments were imposed. Supplementation increased the yield of milk (P < 0.01), protein (P < 0.05) and lactose (P < 0.001), decreased milk fat (P < 0.05) and protein (P < 0.01) concentrations and increased (P < 0.01) lactose concentration. Type of oil did not significantly affect any production variable. The concentration of C18:1 trans 9 + C18:1 trans 11 (mainly C18:1 trans 11) (P < 0.001) and C18:2 cis 9, trans 11 CLA (P < 0.01) were greater on supplemented treatments than on P and the concentration of both were greater (P < 0.05) on FO than on SO. The results confirm that the concentration of C18:2 cis 9, trans 11 CLA can be increased further, from an already relatively high concentration in milk from pasture, by offering supplements containing a low level of fish oil either alone or in combination with sunflower oil.