Diet composition, herbage intake and digestibility in Inner Mongolian Cashmere goats grazing on native Leymus chinensis plant communities

The botanical composition, intake and digestibility of the diet selected by Inner Mongolian Cashmere goats grazing on a native Leymus chinensis plant community were measured in two grazing periods (June and August) using the n-alkane markers. In each grazing period, 48 Inner Mongolian Cashmere goats (24 wethers and 24 does with an average live weight of 22.1 ± 1.2 kg and 19.6 ± 0.8 kg, respectively) were divided in two groups (G1: grazing group; G2: cage-fed group) of 24 animals each. Based on the observation of G1 grazing behaviour, G2 goats were fed on herbage obtained by a simulative method and were housed in metabolism cages to determine the alkane faecal recoveries. Diet composition was estimated by comparing the odd-chain n-alkane pattern (C₂₅–C₃₅) of the selected plant species with the n-alkane faecal concentrations, corrected for their incomplete faecal recovery. The alkane pair C₃₂:C₃₃ and C₃₆ alkane were used to estimate intake and diet digestibility, respectively. The results showed that the increase of herbage availability from June to August, resulted in higher (P < 0.05) DM, CP, ME, ADF and NDF intake of both wethers and does, with no evident changes in ADF and NDF intake in does., The intake of nutrients differed significantly between wethers and does in both experimental periods, except for NDF in EP1 and ME in EP2. Differences between grazing seasons and goats' sex in nutrients digestibility were not observed. Diet composition indicated seasonal differences, being Sonchus brachyotus, Artemisia frigida and Phragmites communis the main components of the diet in June. However, Suaeda corniculata, Chloris virgata, Xanthium sibiricum and Echinochloa crusgalli became the main diet components in August. Moreover, the sex affected significantly the diet choices in both grazing periods.     

Validation of the n-alkane and NIRS techniques to estimate intake, digestibility and diet composition in sheep fed mixed lucerne: ryegrass diets

An experiment was carried out with sixteen non-pregnant, non-lactating adult Rasa Aragonesa ewes fed different proportions of lucerne and ryegrass hays to validate the use of n-alkanes and NIRS methods to estimate diet composition, intake and digestibility. The effect of two different faecal sampling procedures (daily pool (S1) or rectal spot samples (S2)) was also tested. The faecal concentration of n-alkanes was affected by the sampling procedure, although differences were lower than 12%. Faecal recoveries were not affected by diet, except in the case of C₂₃ (P < 0.0001), C₂₈ (P = 0.0264) and C₃₃ (P = 0.0241), and followed a curvilinear pattern with alkane chain length. Recovery was complete in the case of C₂₉, C₃₁ and C₃₃, which countersigns the usefulness of these internal markers for digestibility and digestive flow studies (especially C₃₁, given its high concentration in most plants). The faecal recoveries of C₃₁ and C₃₂ were not similar, the assumption of identity affecting in an important way the reliability of intake estimates. The NIRS methodology appeared as a promising alternative for predicting diet composition (R² of the cross-validation = 0.98) and faecal concentration of most natural alkanes, although that was not the case for dosed alkanes. In all cases, the prediction equations obtained from the spectra of the faecal spot samples were better than those obtained from daily pool samples.     

Maize silage particle length modulates feeding patterns and milk composition in loose-housed lactating Holstein cows

This study analysed feeding patterns and feed selective consumption by loose-housed lactating dairy cows fed diets based on maize silage (MS) with different particle length (PL) to establish its effects on overall dry matter intake (DMI) and productive performance. Twelve multiparous Holstein cows were offered a total mixed ration (TMR) with three different PL of MS at harvesting (i.e., long, medium, and short). Results demonstrated greater numbers of day-time meals (i.e., 07:30–19:00 h) when PL was decreased from long to medium (P < 0.05). Night-time (i.e., 19:00–06:30 h) changes in the feeding pattern included an increased amount of feed per meal (P < 0.05) and a tendency to increase eating time per meal (P < 0.10) in cows fed the short-PL diet. Lowering the PL of MS also lowered the selective consumption against physically effective fibre larger than 1.18 mm (peNDF_> 1.18; P < 0.05) and in favour of fine particles (i.e., particles passing through 1.18 mm screen; P < 0.01). Decreasing PL of MS from long to medium and short increased daily DMI as well as the intake of energy and other nutrients contained in the diet including the amount of peNDF_> 1.18 (P < 0.01). The decrease in the PL of the diet also was associated with increased milk protein and lactose yield and milk urea nitrogen (P < 0.05). The actual milk yield and fat-corrected milk were not affected by the diet (P > 0.10). Although lowering of the PL tended to increase daily milk energy output (P < 0.10), the ratio between energy milk output and the energy intake was linearly decreased (P < 0.01), indicating a lower milk efficiency for the lower-PL diets. In conclusion, particle length of MS in a TMR has the potential to modulate circadian feeding patterns, selective consumption of the feed, daily DMI, and milk composition in high-producing dairy cows.     

Accuracy of the n-alkane technique for intake estimates in beef cattle using different sampling procedures and feeding levels

The present study aimed to evaluate the reliability of the n-alkane technique for estimating herbage intake in beef cattle receiving two different feeding levels (low and high) and to test the effect of different faeces sampling procedures (total faeces samples or rectal grab samples at 8 h intervals) on the n-alkane faecal recoveries and hence on intake estimates. Two consecutive experiments were performed with 11 non-lactating beef cows of “Asturiana de los Valles” breed, fed with lucerne hay at two feeding levels: 1.0 or 1.7 kg DM/100 kg body weight (BW). Animals received a daily dose of paper pellets containing C₂₄, C₃₂ and C₃₆ n-alkanes as external markers with the purpose of using different n-alkane pairs of adjacent chain length (C₂₃/C₂₄, C₂₅/C₂₄, C₃₁/C₃₂, C₃₃/C₃₂, C₃₅/C₃₆) for intake calculations. A 5-day equilibrium period was sufficient for external marker concentrations and n-alkane pair ratios to reach steady state in faeces. There was no effect of different sampling times (every 8 h) on the faecal excretion of n-alkane pairs C₃₁/C₃₂ and C₃₃/C₃₂. Grab samples obtained at the time of dosing (0830 h) gave the best estimate of n-alkane pair ratios in total faeces collection. There was a general trend of increasing n-alkane faecal recoveries with increased chain length, although n-alkanes C₃₀, C₃₁ and C₃₃ showed lower faecal recoveries than expected. n-Alkane recoveries were in general lower at the low feeding level, where an increase in individual variability of natural n-alkane recoveries was observed. At both feeding levels, the n-alkane pairs C₂₃/C₂₄ and C₃₅/C₃₆ gave accurate estimates of the treatment average intake, although the natural n-alkane (C₂₃ or C₃₅) faecal recoveries showed high individual variability, which could be in part due to analytical bias caused by their extremely low concentration in the diet and faeces. However, the n-alkane pairs C₃₁/C₃₂ and C₃₃/C₃₂ gave the greatest deviations of intake estimates, due to the high discrepancy between the faecal recoveries of natural and dosed n-alkanes. These results demonstrate that in beef cattle, feeding level may have some influence on the relative faecal recoveries of the n-alkane pair used for intake calculations. This effect, together with the high individual variability of n-alkane recoveries, especially under low feeding level, may produce significant deviations of the individual intake estimates.     

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.     

Effect of varying ruminally degradable to ruminally undegradable protein ratio on nutrient intake, digestibility and N metabolism in Nili Ravi buffalo calves (Bubalus bubalis)

Four Nili-Ravi buffalo calves (100 ± 4 kg) were used in 4 × 4 Latin Square Design to evaluate the influence of varying ruminally degradable protein (RDP) to ruminally undegradable protein (RUP) ratio on dry matter intake (DMI), digestibility and nitrogen (N) metabolism. Four experimental diets A, B, C and D were formulated to contain RDP:RUP of 70:30, 65:35, 60:40 and 55:45, respectively. The calves were fed ad libitum. Dry matter intake by calves fed C diet was higher (P < 0.05) than those fed D diet and lower (P < 0.05) than calves fed A diet, however, it was similar to those fed B diet. There was a linear decrease (P < 0.01) in DMI with decreasing the RDP to RUP ratio. Similar trend was noticed in crude protein (CP) intake. Neutral detergent fiber (NDF) intake was significantly different across all treatment. The decrease in CP and NDF intake was due to decreasing trend of DMI. Dry matter (DM) digestibility in calves fed A and B diets was higher (P < 0.05) than those fed C and D diets. A linear decrease (P < 0.01) in DM digestibility was observed with decreasing the RDP to RUP ratio. Crude protein digestibility remained unaltered across all treatments. Neutral detergent fiber digestibility was higher in calves fed A and B diets than those fed C and D diets. Higher NDF digestibility in calves fed A and B diets was due to higher level of dietary RDP that might resulted in higher ruminal ammonia concentration which stimulate activity of cellulytic bacteria and ultimately increased NDF digestibility. The N retention (g/d) was similar among the calves fed B, C and D diets, however, it was higher (P < 0.05) than those fed A diet. Decreasing the RDP to RUP ratio resulted in linear increase (P < 0.01) in N retention. The N retention, as percent of N intake was significantly different across all treatments. Decreasing RDP to RUP ratio resulted in linear increase (P < 0.01) in N retention, as percent of N intake. A similar trend was noticed in N retention, as percentage of N digestion. Blood urea nitrogen (BUN) concentration in calves fed B diet was higher (P < 0.05) than those fed D diet and was lower (P < 0.05) than those fed A diet, however, it was not different from calves fed C diet. Decreasing dietary RDP to RUP ratio resulted in linear decrease (P < 0.05) in BUN concentrations. The decrease in BUN concentration was because of decreasing level of dietary RDP. The N retention can be increased by decreasing RDP to RUP ratio in the diet of growing buffalo calves and diet containing RDP to RUP ratio 55:45 is considered optimum regarding N retention in buffalo calves.     

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.     

Effect of magnesium sulphate and l-tryptophan and genotype on the feed intake, behaviour and meat quality of pigs

Sixty-nine entire male pigs with different halothane genotype (homozygous halothane positive — nn-, n = 36; and homozygous halothane negative — NN-, n = 33) were fed with a supplementation of magnesium sulphate (Mg) and/or l-tryptophan (Trp) in the diet for 5 days before slaughter. Animals were housed individually and were submitted to stressful ante mortem conditions (mixed in the lorry according to treatments and transported 1 h on rough roads). Individual feed intake was recorded during the 5-d treatment. At the abattoir, pig behaviour was assessed in the raceway to the stunning system and during the stunning period by exposure to CO₂. Muscle pH, colour, water holding capacity, texture and cathepsin activities were determined to assess meat quality. The number of pigs with an individual feed intake lower than 2 kg/day was significantly different among diets (P < 0.05; Control: 8.7%; Mg&Trp: 43.5%; Trp: 17.4%) and they were considered to have inadequate supplement intake. During the ante mortem period, 15.2% of pigs included in the experiment died, and this percentage decreased to 8.7% in those pigs with a feed intake > 2 kg/day, all of them from the stress-sensitive pigs (nn). In general, no differences were observed in the behaviour of pigs along the corridor leading to the stunning system and inside the CO₂ stunning system. During the stunning procedure, Trp diet showed shorter periods of muscular excitation than control and Mg&Trp diets. The combination of a stressful ante mortem treatment and Mg&Trp supplementation led to carcasses with high incidence of severe skin lesions. Different meat quality results were found when considering all pigs or considering only those with adequate supplement intake. In this later case, Trp increased pH₄₅ (6.15) vs Control diet (5.96) in the Longissimus thoracis (LT) muscle (P < 0.05) and pH at 24 h (Trp: 5.59 vs C: 5.47) led to a higher incidence of dark, firm and exudative (DFD) traits in SM muscle (P < 0.05). Genotype affected negatively all the meat quality traits. Seventy-five percent of LT and 60.0% of the SM muscles from nn pigs were classified as pale, soft and exudative (PSE), while none of the NN pigs showed these traits (P < 0.0001). No significant differences were found between genotypes on the incidence of DFD meat.Due to the negative effects observed in the Mg&Trp group in feed intake and carcass quality, the utilization of a mixture of magnesium sulphate and tryptophan is not recommended.     

Utilization of citrus pulp based diets and Enterolobium cyclocarpum (JACQ. GRISEB) foliage by West African dwarf goats

Sixteen West African dwarf goats weighing 5.0–5.6 kg were used in an experiment that lasted 112 days to investigate the utilization of citrus pulp based diets and E. cyclocarpum. A control diet which contained 88.5% dried brewers' grains (DBG) and other three experimental diets in which DBG was replaced with dried citrus pulp (DCP) at 25, 50 and 75% levels, respectively constituted the four treatments. The goats were divided into four groups of four animals each to balance for variation in live weight before they were assigned to the four different experimental diets. Significant differences (P < 0.05) were obtained in growth rate with (22.14–34.02 g/d) the highest and lowest value from 50 and 75% DCP inclusion respectively. The digestibility coefficients of DM, Ash, NFE, NDF, ADL, cellulose and hemicellulose increased with increasing levels of dried citrus pulp in the diets and were highest at 75% level of replacement. However, the CP digestibility of 83.85% was highest in the control diet and was significantly (P < 0.05) different from other diets containing citrus pulp. Nitrogen intake (g/d) decreased significantly (P < 0.05) with increasing levels of dried citrus pulp in the diets from 45.57–33.28 and was lowest in the control diet. Nitrogen balance also followed the same trend, being highest (42.07 g/d) at 25% DCP and lowest at 75% DCP. The Packed cell volume (PCV), haemoglobin concentration (Hb), red blood cells (RBC), white blood cells (WBC) and total blood protein (TBP) were significantly (P < 0.05) different across the dietary treatments at the start and end of the trial. The values for PCV, RBC, MCH, glucose and total protein decreased slightly in the control diet. Serum glutamate pyruvate transaminase (SGPT) values also increased significantly (P < 0.05) with increasing levels of dried citrus pulp in the diets at the end of the experiment and were highest (6.50 IU/L) at 75% level of citrus pulp. Therefore, the efficient utilization of citrus pulp and E. cyclocarpum by WAD goats was attained at the 50% level of inclusion in the diets.     

Supplementation of cottonseed meal on feed intake, digestibility, live weight and carcass parameters of Sidama goats

The experiment was conducted at Dilla Agricultural Technical Vocational Education and Training (ATVET) College in Ethiopia using twenty-four yearling intact male Sidama goats with a mean body weight (BW) of 16.8 ± 1.14 kg (mean ± SD). The objective of the experiment was to examine the effect of different levels of cottonseed meal (CSM) supplementation on the feed intake, digestibility, BW gain, and carcass parameters of Sidama goats. The experiment consisted of 90 days of feeding trial and 10 days of digestibility trial followed by evaluation of carcass parameters at the end of the experiment. The treatments included ad libitum feeding of hay (T1, control) and daily supplementation of CSM at 200 g (T2), 300 g (T3) and 400 g (T4) per head on dry matter (DM) basis. The experimental design was a completely randomized block design. The experimental goats were blocked on initial BW and six goats were randomly assigned to each treatment. Hay DM, crude protein (CP) and neutral detergent fiber (NDF) intake were higher (P < 0.001) in the non-supplemented than in the supplemented goats, however, the contrary was true for total CP intake. Total DM intake was higher (P < 0.001) for goats supplemented with the high level of CSM than those on the control treatment. Among CSM supplemented goats, the intake of CSM DM, CP, NDF (P < 0.001) and total CP (P < 0.01) were higher in the order of T4 > T3 > T2. The high level of supplementation with CSM resulted in better (P < 0.05) apparent digestibility coefficient (DC) of DM and organic matter (OM) compared to the non-supplemented goats. The apparent DC of CP was higher (P < 0.01) for supplemented than non-supplemented goats. The non-supplemented goats had lower daily BW gain, empty BW, dressing percentage on slaughter weight base, rib-eye muscle area (P < 0.01), BW change (P < 0.001), final BW (P < 0.05) and higher feed conversion ratio (P < 0.01) than the supplemented ones. The medium level of supplementation resulted in higher daily BW gain (P < 0.01), BW change (P < 0.001), final BW (P < 0.05) and lower feed conversion ratio (P < 0.01) than the lower level of supplementation, but with no differences (P > 0.05) in these parameters with the high level of supplementation. Therefore, it is concluded that supplementation of CSM at 300 g DM per head per day resulted in better animal performance parameters in Sidama goats.     

Effects of Ca salt supplementation on milk yield and composition and on lamb growth rate of Awassi ewes

An experiment was conducted to evaluate the effect of a Ca salt supplement on lactating Awassi ewes and their lambs. Ninety Awassi ewes (average BW = 55 kg ± 1.13) were allocated into three treatment groups of 30 each; 0%, 3%, or 5% Ca salt supplemented groups. The experiment started at lambing and lasted for 60 d. During this period, milk production and composition, final body weights, total feed intake, serum cholesterol and triglycerides, weaning weights of lambs, and milk fatty acid profile were tested. Milk production and energy corrected milk increased (P < 0.05) with Ca salt level in the diet. Milk fat content was higher (P < 0.05) at 3% treatment group compared to 0% and 5% treatment groups. However, no differences were detected in content of crude protein and total solids, and milk energy value. Milk fat yield (g/d) increased (P < 0.05) as Ca salt in the diet increased. Final body weight was higher (P < 0.05) for 5% group when compared to the 0% group with no differences between the 3% group when compared to 0% and 5% groups. No differences were observed in feed intake of ewes. Metabolizable energy intake was greater (P < 0.05) for the 3% and the 5% treatment groups when compared to the 0% treatment group. Feed to milk ratio increased (P < 0.05) when increasing the level of Ca salt in the diet. Serum cholesterol was greater (P < 0.05) in the 5% treatment group than the 0% and 3% treatment groups for ewes and lambs. Serum triglyceride was similar among treatment groups in ewes whereas serum triglyceride was greater (P < 0.05) for lambs in 5% treatment group than 0% and 3% treatment groups. However, serum triglyceride was similar in ewes among treatment groups. Weaning weights and average daily gain of male lambs were higher (P < 0.05) in lambs fed Ca salt (3% and 5%) when compared to 0% treatment group. No differences were detected in weaning weights and average daily gain of female lambs among treatment groups. However, milk conversion ratio was better (P < 0.05) for the 5% group lambs than the 0% and 3% treatment groups. Ca salt reduced (P < 0.05) short and medium-chain milk fatty acids and increased (P < 0.05) content of long chain and unsaturated ones. These results of this indicate that Ca salt supplementation can improve milk production of lactating ewes, the growth rate of their lambs, and produce healthy quality value milk.     

Increasing feed withdrawal and lairage times prior to slaughter decreases the gastrointestinal tract weight but favours the growth of cecal Enterobacteriaceae in pigs

The objective of this study was to evaluate the influence of different feed withdrawal and lairage times prior to slaughter on the gastrointestinal tract (GIT) weight and on the fermentation pattern and numbers of Enterobacteriaceae in the cecum of pigs. A total of 72 finishing pigs (6 pens, 12 animals each) were included in the study and were sent to the slaughterhouse on three consecutive days. On each day pigs from two pens were deprived of feed for either 2 or 12 h before leaving the farm. Pigs from each of the two pens were divided in sub-groups (4 pigs each) on the moment of loading onto the truck and followed the same distribution at the slaughterhouse. Once there, each sub-group corresponding to the same feed withdrawal time was held in different holding pens for 0, 5 or 10 h before slaughter. The weight of the gastro-intestinal tract (GIT) was determined and cecal content was collected to evaluate pH, short chain fatty acids (SCFA) and ammonia (NH₃) concentrations as well as lactobacilli and Enterobacteriaceae numbers. Total GIT weight decreased as feed withdrawal (P < 0.0001) and lairage time (P < 0.001) increased within a range between 6.69 and 4.59 kg. Cecal pH increased with feed withdrawal (P < 0.0001) and lairage time (P = 0.0001) (ranging from 5.79 to 6.79) in parallel to a decrease in the total SCFA concentration (P < 0.005) (from 211 to 100 mM). The percentages of acetic and propionic acid were not modified by the experimental treatments but significant decreases were registered in the percentage of butyric acid with the increased times of both withdrawal (P < 0.0001) and lairage (P < 0.005). The percentage of valeric and branched SCFA and also NH₃ concentration showed an increase with withdrawal (P < 0.005, P < 0.0001 and P < 0.005 respectively) and lairage (P < 0.005, P < 0.0001 and P < 0.001 respectively). Lactobacilli numbers decreased as lairage time increased (from 9.97 to 8.63 log 16S rRNA gene copies/g FM; P < 0.05) and Enterobacteriaceae numbers increased with both, feed withdrawal (P < 0.05) and lairage (P < 0.05) (ranging from 8.53 to 9.95 log 16S rRNA gene copies/g FM).The previous to slaughter increase in feed withdrawal and lairage times decreased the GIT weight but involved changes in the gut microbial ecosystem caused through changes in the fermentation pattern that lead to the increase of Enterobacteriaceae numbers. This increase could represent a higher risk of carcass contamination by the enteropathogens of this group such as Salmonella. However this potential risk should be further investigated.     

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.     

Intake, live animal scores/measurements and carcass composition and value of late-maturing beef and dairy breeds

The objectives of this study were to compare the progeny of 1) late-maturing beef with dairy breeds and 2) Charolais (CH), Limousin (LM), Simmental (SM) and Belgian Blue (BB) sires bred to beef suckler dams, for feed intake, blood hormones and metabolites, live animal measurements, carcass traits and carcass value in bull and steer production systems. The bull system included 50 late-maturing beef breeds and 22 Holsteins (HO) slaughtered at approximately 15 months of age, whereas the steer system consisted of 56 late-maturing beef breeds and 23 British Friesians (FR) slaughtered at approximately 24 months of age. Beef breeds were suckled until approximately 8 months of age, while dairy breeds were artificially reared until weaning at approximately 3 months of age. All animals were finished on an ad libitum concentrate diet. Mean live weight, live weight gain, carcass gain and feed efficiency were greater (P < 0.05) in beef than dairy breeds in both systems during the finishing period when offered concentrates. Although there was no difference in feed intake between beef and dairy breeds, intake expressed relative to live weight was lower (P < 0.001) in beef breeds in both systems. At 10 months of age and pre-slaughter, beef breeds had higher (P < 0.001) muscularity scores and greater scanned muscle depth (P < 0.001) than their dairy contemporaries. Carcass weight, kill-out proportion, carcass conformation score, meat proportion and value were greater (P < 0.001) and carcass fat and bone proportions were lower (P < 0.05) in beef than dairy breeds in both systems. Insulin concentrations were lower (P < 0.001) in beef than dairy breeds, whereas there was no difference in blood metabolites or IGF-1 concentrations. Feed intake expressed relative to live weight or feed efficiency did not differ between CH, LM, SM or BB sired progeny. Muscularity scores were greater (P < 0.05) in BB than SM, whereas skeletal scores were lower (P < 0.05) in LM than SM. Limousin had lower (P < 0.05) carcass gain per day of age than CH and SM, whereas SM had a lower (P < 0.05) carcass conformation score than BB and CH and a higher (P < 0.05) carcass fat score than CH. Simmental had a lower (P < 0.05) carcass meat proportion and a higher (P < 0.05) carcass fat proportion than CH, LM and BB, which were similar (P > 0.05). The improvement obtained for beef over dairy breeds in live weight gain was 12%, while the improvements in carcass gain and meat produced was 24% and 33%, respectively. This demonstrates that the importance of carcass data contributing to breed comparison studies cannot be over-emphasised.     

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.     

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.     

Polyethylene glycol influences feeding behaviour of dairy goats browsing on bushland with different herbage cover

The effects of supplemental polyethylene glycol (PEG) on feeding behaviour, diet composition, intake and milk production were studied in late lactating Sarda goats browsing on a lentisk-based bushland with different herbage cover. The goats were allotted to two groups that browsed 7 h daily on 2 plots characterised by different cover proportions of woody and herbaceous species. These proportions were 90% woody vs. 10% herbaceous species in one plot (W — woody, close bushland with low herbage cover) and 70% woody vs. 30% herbaceous species in the other plot (H — herbaceous, open bushland with high herbage cover). Each group was divided into two sub-groups: one fed with 50 g day^− 1 of PEG 4000 MW (PEG⁺) and the other receiving no PEG supplementation (PEG⁻). The feeding behaviour was different between groups; goats in herbaceous plot (H-goats), had a longer grazing time, expressed as percentage of total observation time than the counterparts (64% vs. 58%, P < 0.05). The intake was not affected by the treatments. The percentage of the species eaten by the goats was different in the two groups: H-goats ate more herbaceous and less woody species than goats in woody plot (W-goats). In each group the PEG tended to affect the botanical composition of the diet. PEG dosed goats ate more tanniferous species than control counterparts (P = 0.12). The average daily milk production was 473, 591, 541 and 589 ml, respectively in W-PEG^−, W-PEG⁺, H-PEG⁻ and H-PEG⁺ sub-groups with significant effect of herbage cover × PEG dose interaction (P < 0.05). The milk urea was affected by herbage cover (P < 0.001) and PEG supplementation (P < 0.001). In conclusion, the effect of PEG is strictly dependent on pasture composition. In open bushland, featured by moderate woody cover, the effect of PEG is more intense on diet selection, due to its marked post-ingestive effects. In close bushland, characterised by high proportion of tanniferous species prevails the efficacy of PEG as a performance booster.     

The response of Japanese quails (heavy body weight line) to dietary energy levels and graded essential amino acid levels on growth performance and immuno-competence

The response of growing quails (n = 900, divided into 36 subgroups) to dietary levels of essential amino acids (EAA) at different energy levels on growth and immunity was investigated. Nine diets including three levels of metabolizable energy (ME, 11.30, 12.13 and 12.97 MJ ME kg^− 1) each at three levels of EAA (low, medium and high) in a 3 × 3 factorial design were formulated. Each diet was offered to 4 replicated groups up to 5 weeks of age. The ratio of lysine to protein and the level of methionine and threonine to lysine remained almost similar in all the diets as specified by NRC [NRC, 1994. Pages 44–45 in Nutrients requirements of poultry. 8th ed. Natl. Acad. Press, Washington, DC.]. Body weight gain, feed intake and feed conversion ratio did not differ statistically due to the treatments i.e. interaction of ME and EAA levels. However, there was linear increase in body weight gain with increased EAA levels during 0–3 or 0–5 weeks of age. Feed intake increased linearly with the decreased ME (P < <0.01) and increased EAA (P < 0.01) in diets. Feed conversion ratio (FCR) improved (P < 0.01) linearly with increase in dietary ME concentration from 0–3 or 0–5 weeks of age. FCR and energy efficiency improved in diets with medium and high levels of EAA during 0–3 weeks, while it did not differ during 0–5 weeks of age. Protein efficiency (PE) improved linearly (P < 0.01) with decreased EAA levels during 0–3 or 0–5 weeks of age, and also with the increase in dietary ME level during 0–5 weeks growth phase. Nitrogen retention per unit energy intake was significantly higher in diet containing 12.97 MJ ME kg^− 1 with high level of EAA. Humoral (SRBC) and cellular (PHA-P) immune response and yield of immune organs did not differ due to ME, EAA or ME x EAA. Therefore, it can be concluded that the optimum level of dietary ME is 11.30 MJ kg^− 1 with CP 25.83%, lysine 1.49%, methionine 0.58% and threonine 1.17% on dry matter basis during 0–5 weeks of age for gain. However for optimum feed conversion, the growing quails require diet with ME 12.97 MJ kg^− 1 with CP 23.23%, lysine 1.30%, methionine 0.50% and threonine 1.02% for 0–5 weeks of age.     

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.