Estimation of feed intake and apparent digestibility of equines and cattle grazing on heathland vegetation communities using the n-alkane markers

The application of n-alkanes as faecal markers to estimate feed intake and apparent digestibility (DMD_ap) of equines and cattle was studied. Additionally, the effect of using different data on diet composition, known proportions of the diet components (DC1) and those estimated using the alkane markers (DC2), on the accuracy of intake and DMD_ap estimates was evaluated. Six mature horses, divided in two groups of three animals (H1 and H2), and three adult non-lactating cows of Asturiana de los Valles breed (C) were housed in individual stalls. H1 and C groups were fed on a diet composed of Lolium perenne L. (70%) and heather (30%) and H2 received L. perenne (40%), heather (30%) and Ulex gallii Planchon (30%). The dietary component heather represented the field proportions of different plant species of heathland, namely Erica umbellata L., Erica cinerea L. and Calluna vulgaris L., at this experimental period. All 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 for feed intake estimations. The results indicated that a period of 3 and 5 days was sufficient for these external markers to reach a steady concentration in faeces of cattle and equines, respectively. In contrast to the results obtained in cattle, the alkane faecal recovery in equines was unrelated to the carbon chain length. Diet composition only affected the faecal recovery of the alkanes C₂₄ (P < 0.05), C₃₁ (P < 0.05), C₃₂ (P < 0.05) and C₃₆ (P < 0.01) in the faeces of the equines, suggesting a different dispersion of the synthetic n-alkanes in the digesta. In equines, DMD_ap estimates were not affected by the n-alkane (C₂₇, C₂₉, C₃₁ and C₃₃) used in the calculations, contrasting with the significant (P < 0.001) effect observed in cattle. In both animal species, the data on diet composition (DC1 or DC2) used in the calculations did not affect DMD_ap estimates. Feed intake estimates were affected by the alkane pair used in the calculations in H1 (P < 0.05), H2 (P < 0.001) and C (P < 0.001). The data on diet composition used in the intake calculations affected the resultant estimates in H1 (P < 0.05) but not in H2 and C. The differences from the known intake values were lower when using C₃₁:C₃₂ alkane pair, overestimating intake in only an average of 4.5, 13.0 and 1.3% in H1, H2 and C, respectively, using DC1 or DC2. The results obtained in this study confirm the accuracy of the n-alkane markers to estimate simultaneously feed intake, apparent digestibility and diet composition of equines and cattle grazing these type vegetation communities.     

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.     

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.     

Faecal nitrogen excretion as an approach to estimate forage intake of wethers

Data from twenty‐two digestibility trials were compiled to examine the relationship between faecal N concentration and organic matter (OM) digestibility (OMD), and between faecal N excretion and OM intake (OMI) by wethers fed tropical or temperate forages alone or with supplements. Data set was grouped by diet type as follows: only tropical grass (n = 204), only temperate grass (n = 160), tropical grass plus supplement (n = 216), temperate grass plus supplement (n = 48), tropical grass plus tropical legume (n = 60) and temperate grass with ruminal infusion of tannins (n = 16). Positive correlation between OMD and either total faecal N concentration (Nfc, % of OM) or metabolic faecal N concentration (Nmetfc, % of OM) was significant for most diet types. Exceptions were the diet that included a tropical legume, where both relationships were negative, and the diet that included tannin extract, where the correlation between OMD and Nfc was not significant. Pearson correlation and linear regressions between OM intake (OMI, g/day) and faecal N excretion (Nf, g/day) were significant for all diet types. When OMI was estimated from the OM faecal excretion and Nfc‐based OMD values, the linear comparison between observed and estimated OMI values showed intercept different from 0 and slope different from 1. When OMI was estimated using the Nf‐based linear regressions, the linear comparison between observed and estimated OMI values showed neither intercept different from 0 nor slope different from 1. Both linear comparisons showed similar R² values (i.e. 0.78 vs. 0.79). In conclusion, linear equations are suitable for directly estimating OM intake by wethers, fed only forage or forage plus supplements, from the amount of N excreted in faeces. The use of this approach in experiments with grazing wethers has the advantage of accounting for individual variations in diet selection and digestion processes and precludes the use of techniques to estimate forage digestibility.     

Effect of oak (Quercus persica) acorn level on apparent digestibility,ruminal fermentation,nitrogen balance and urinary purine derivatives in pregnant goats

The aim of this experiment was to investigate the effect of dietary oak (Quercus persica) acorn (OA) level on dry matter intake (DMI), apparent nutrient digestibility, nitrogen (N) utilization, ruminal fermentation, protozoa population and urinary purine derivatives (PD) during the last 60 days of goat pregnancy. Twenty‐four multiparous pregnant goats (41.7 ± 2.3 kg BW) were assigned to one of three experimental diets consisted of control diet (C, without OA) and diets containing 20 (OA₂₀) or 40 g/100 g of OA (OA₄₀) on a DM basis in a completely randomized block design. Goats fed OA₄₀ had lower DMI (p < .01), DM (p < .01), OM (p < .01) and NDF (p < .05) digestibility, ruminal NH₃‐N concentration (p < .01), N intake (p < .01) and N retention (p < .01). Crude protein digestibility and ruminal acetate and total volatile fatty acid (VFA) concentration were lower in animals fed OA‐contained diets (p < .01), whereas ruminal propionate concentration was higher in goats fed the C diet (p < .01). Animals fed OA₄₀ had higher faecal N excretion and lower urinary N excretion (p < .01). Urinary PD was lower in goats fed diets containing OA in relation to those fed the C diet (p < .01). Total protozoa population decreased linearly with increasing OA level in the diet (p < .05). These results suggest that feeding OA, especially high level, has negative impacts on DMI, nutrient digestibility, VFA concentration, N retention and urinary PD excretion that may have adverse effects on metabolism and performance of pregnant goats.     

Does the level of forage neutral detergent fiber affect the ruminal fermentation,digestibility and feeding behavior of goats fed cactus pear?

This study aimed to evaluate the effects of forage neutral detergent fiber (fNDF) levels on the voluntary feed intake, digestibility, ruminal fermentation and feeding behavior of goats fed diets with cactus pear. Five non‐lactating ruminally cannulated goats fed ad libitum were randomly assigned to a 5 × 5 Latin square design. Treatments consisted of levels of fNDF at 0, 109, 222, 339 and 463 g/kg of dry matter (DM) in cactus pear‐based diets. The intakes of DM and NDF were quadratically affected (p ≦ .045) by fNDF levels. Voluntary water intake (VWI) increased linearly as the fNDF levels increased in the diet. The digestibility coefficients of organic matter, NDF and ether extract and total digestible nutrients concentration were quadratically affected (p ≦ .048) by fNDF levels. The ruminal pH linearly increased (p = .001) with fNDF levels, ranging from 5.44 to 5.81 for diets containing 0 and 463 g fNDF/kg DM, respectively. The fNDF levels promoted a linear increase (p = .006) in chewing time, linearly decreased (p = .007) resting time and quadratically affected (p = .033) rumination time. The inclusion of fNDF in the diets provided favorable conditions for ruminal function, digestibility and feeding behavior in goats fed diets containing cactus pear.     

Replacement of soybean meal with levels of inclusion of soya waste in the diet of growing goats

An experiment was conducted to investigate the effect of replacing soybean meal with soya waste at different levels on intake, digestibility and growth in goats. Eighteen male goat kids with initial body weight (BW) of 13.0 kg were distributed equally to three dietary groups. They were fed Napier grass (Pennisetum purpureum) and concentrate mixture, and each goat was assigned to an individual pen. Soybean meal in the concentrate mixture was replaced with soya waste at 0% (T1), 50% (T2) and 100% (T3) levels in respective dietary groups. These diets were isocaloric and isonitrogenous. Results showed that animals fed T3 diet exhibited higher Napier grass intake than those fed T1 or T2 diet. There was no influence on total intakes of dry matter (DM), organic matter (OM), crude protein (CP), metabolic BW, per cent BW and metabolisable energy by the dietary groups. However, there was an increasing trend on intake and digestibility of neutral detergent fibre (NDF) with increasing levels of soya waste in the diets. Animals fed T3 diet showed higher intake and digestibility of NDF than those fed T1 diet. There was no influence of the dietary groups on digestibilities of DM, OM and CP. Similarly, there was no effect of them on the final BW, total BW gain, daily BW gain, feed conversion ratio and feed cost. Soya waste can replace 100% soybean meal in diets for growing goats, because no change was observed in nutrient intake, digestibility and growth performance; inclusion of soya waste enhanced the intake and digestibility of NDF.

     

Effects of supplementation of Panicum maximum with four herbaceous forage legumes on performance,nutrient digestibility and nitrogen balance in West African dwarf goats

The effects of supplementing a basal diet of guineagrass (Panicum maximum cv Ntchisi) (diet 5) with Stylosanthes guianensis (diet 1), Lablab purpureus (diet 2), Aeschynomene histrix (diet 3) and Centrosema pubescens (diet 5) on West African dwarf goats were evaluated. Parameters measured were feed intake, nutrient digestibility and nitrogen balance. Voluntary intake (g/kg W0^.75/day) of dry matter (DM) 138.73, crude protein (CP) 25.86, neutral detergent fiber (NDF) (96.29) and acid detergent fiber (ADF) (65.73) of diet 1 were not significantly different (P > 0.05) from the other diets with legume supplements. The feed intake of goats on diet 5 was lower (P < 0.05), having corresponding values of DM (108.21), CP (17.33), NDF (77.68), and ADF (53.55). Weight gain (g/day) differed (P < 0.05) in goats placed on the diets. The lowest weight gain was obtained in diet 5. The digestibilities of DM, CP, ADF and acid detergent lignin (ADL) differed (P < 0.05) in diet 1–5 except for NDF digestibility. Nitrogen balance (g/kg W ^0.75/day) ranged from 0.29 in diet 5 to 0.83 in diet 2 (P < 0.05). Similarly, nitrogen retention percentage was highest in diet 2 (35.17), with the lowest value in diet 5 (20.71). It could be concluded that a diet consisting of Panicum maximum with Lablab purpureus supplementation gave the highest performance in weight gain, nitrogen digestibility and nitrogen utilization. However, any of the herbaceous legumes in this study would lead to increased productivity of ruminant livestock.     

Total nutrient digestibility and small intestine starch digestion in Nellore and Angus young bulls fed a whole shelled corn diet

Eighteen Nellore and 18 Angus young bulls with BW of 381 ± 12 kg were randomly assigned into two feeding groups (whole shelled corn [WSC] or ground corn with silage [GC]) to evaluate the interaction of breed and diet on total nutrient digestibility, pancreatic α‐amylase, and maltase activity and SLC5A1expression in the small intestine. Experimental diets (DM basis) included (a) a diet containing 30% corn silage and 70% GC and soya bean meal‐based concentrate and (b) a diet containing 85% WSC and 15% of a soya bean meal‐ and mineral‐based pelleted supplement. The treatments were Nellore fed GC diet; Nellore fed WSC diet; Angus fed GC diet; and Angus fed WSC diet. Total faecal collection for the digestibility trial occurred from day 48 until day 50 of the experimental period. Feeding the WSC diet reduced DM and NDF intake (p < 0.01). Angus had greater DM and nutrient intake in kg/day (p < 0.01). However, there was no breed effect on DM and nutrient intakes based on percentage of BW (p > 0.19). Angus had greater starch digestibility (p = 0.03) than Nellore. Cattle fed the WSC diet had greater DM, NDF and starch digestibility (p < 0.01) compared with those fed the GC diet. The activity of pancreatic α‐amylase (U/g of protein) was greater in Nellore (p < 0.01) and was not affected by diet (p = 0.52). In duodenum, maltase activity (U/g of protein) was greater in bulls fed GC diet (p = 0.02). Expression of the gene SLC5A1was not affected by breed or diet (p > 0.05). In conclusion, Nellore had less capacity to digest starch. However, they did not have less pancreatic α‐amylase and duodenal maltase activity compared to Angus. The use of the WSC diet increases DM and total nutrient digestibility.     

豆秸加工方式和用量对辽宁绒山羊日粮营养物质消化代谢的影响

试验选用24只2.5岁,体况良好,体重相近(36.02±1.62)kg的辽宁绒山羊公羊,采用2×3因子设计,研究了豆秸加工方式(揉搓5~7 cm,揉搓1~3 cm)和添加量(豆秸占粗饲料比例为30%、50%、70%)对辽宁绒山羊日粮营养物质消化和氮代谢的影响。结果表明:随着豆秸添加量的增加,粗饲料干物质采食量(P<0.05),NDF摄入量显著降低(P<0.01),NDF消化率(P<0.01),食入氮(P<0.01),可消化氮(P<0.01)和沉积氮显著降低(P<0.01);揉碎豆秸组氮表观消化率、氮的总利用率显著高于揉切豆秸组(P<0.05),不同加工方式的可消化氮、氮沉积和NDF消化率均无显著差异(P>0.05)。加工方式和豆秸添加量对食入氮、可消化氮的互作效应显著(P<0.01),表现为30%揉碎豆秸组的食入氮和可消化氮低于50%揉碎豆秸组。豆秸添加量的增加,降低了粗饲料干物质采食量、纤维消化率、氮沉积;揉搓粒度1~3 cm提高了氮表观消化率和氮的总利用率,但倾向于降低食入氮,对可消化氮、沉积氮和纤维物质消化率无显著影响。     

Intake,digestibility, ingestive behavior,and nitrogen balance of goats fed with diets containing residue from tamarind fruit

This study is aimed at determining the maximum inclusion level of tamarind (Tamarindus indica) residues in the diet of goats on intake, digestibility, ingestive behavior, and nitrogen (N) balance. Twenty-four crossbred (Boer × undefined breed) castrated goat kids (5 months old and with an initial weight of 23.9?±?0.3 kg) were assigned in a completely randomized design (4 treatments and 6 replicates). Diets consisted of Tifton 85 (Cynodon sp.) hay as the roughage (400 g/kg) source and concentrate (600 g/kg); the levels of tamarind residue inclusion were 0.0, 7.0, 14.0, and 21.0% on a dry matter (DM) basis. The experimental period lasted 23 days (15 of adaptation and 8 of sampling). Inclusion of tamarind residue in the goat kid diets did not affect (P?>?0.05) the intake and digestibility of DM, crude protein, neutral detergent fiber (NDF), and total digestible nutrient; intake of N, urinary N, and retained N (g/day); time spent ruminating; numbers of times/day feeding, ruminating, or idling; eating efficiency of DM and NDF; number of boluses/day; and amount (g) of DM/bolus. However, there were a linear reduction in ether extract digestibility (P?=?0.011) and a linear decreasing trend in non-fibrous carbohydrate digestibility (P?=?0.083). The addition of tamarind residue had a positive linear effect (P?=?0.041) on the time spent feeding and promoted a decreasing linear trend for the time spent idling (P?=?0.063). It is recommended to include the residue from tamarind fruit at a level of 21% in diets for goat kids, as it does not affect nutrient intake and digestibility and the N balance.

     

Comparison of feed intake,digestion and rumen function among domestic ruminant species grazing in upland vegetation communities

This study aimed to compare feed intake, digestion, rumen fermentation parameters and bacterial community of 5 beef cows, 12 crossed ewes and 12 goats grazing together in spring–early summer on heather–gorse vegetation communities with an adjacent area of improved pasture. Organic matter intake (OMI) and digestibility (OMD) were estimated using alkane markers. Ruminal fluid samples were collected for measuring fermentation parameters, and studying the bacterial community using terminal restriction fragment length polymorphism (T‐RFLP). Spot samples of urine were taken to determine purine derivative (PD) and creatinine concentrations to estimate microbial protein synthesis in the rumen. Herbaceous species were the main dietary component in all animal species. Cattle had higher (p < 0.05) daily OMI (g/kg LW^0.75) and OMD, whereas sheep and goats showed similar values. The highest ammonia concentration was observed in sheep. Total VFA, acetate and butyrate concentrations were not influenced by animal species, while propionate concentrations in goats were 1.8 times lower (p < 0.05) than in sheep. Acetate:propionate ratio was greater (p < 0.05) in goats, whereas cattle excreted more allantoin (p < 0.05). Estimated supply of microbial N was higher in cows (p < 0.01), whereas the efficiency of microbial protein synthesis was lower (p < 0.01) in this animal species. Hierarchical clustering analysis indicated a clear effect of animal species on rumen bacterial structure. Differences among animal species were also observed in the relative frequency of several T‐RFs. Certain T‐RFs compatible with Lachnospiraceae, Proteobacteria and Clostridiales species were not found in goats, while these animals showed high relative frequencies of some fragments compatible with the Ruminococcaceae family that were not detected in sheep and cattle. Results suggest a close relationship between animals’ grazing behaviour and rumen bacterial structure and its function. Goats seem to show a greater specialization of their microbial populations to deal with the greater fibrous and tannin content of their diet.     

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.     

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.     

Performance of growing indigenous goats fed diets based on urban market crop wastes

The effect of feeding diets including market crop wastes (sweet potato vines (Ipomoea batatas) and scarlet eggplant (Solanum aethiopicum)) on growth and digestibility was studied using 32 indigenous intact growing male goats. Adding elephant grass (Pennisetum purpureum), maize bran and Leucaena leucocephala leaves, four isocaloric and isonitrogenous diets (Sweet potato vines, Solanum, Mixed and Control) were formulated. After the growth trial, 12 goats were randomly selected for a digestibility trial with the same diets, and 8 goats for a feed preference test comparing the market wastes and elephant grass. Crude protein (CP) intake was highest (P < 0.05) for the Control (48 g/day) and lowest for the Sweet potato vines diet (23 g/day). Average daily gain was between 11.0 and 14.2 g/day, and similar between diets. The DM and CP digestibilities of the diets were 0.56 and 0.56 (Control), 0.62 and 0.56 (Mixed), 0.59 and 0.49 (Sweet potato vines), and 0.54 and 0.45 (Solanum), respectively. Faecal and urinary N excretions were highest in goats fed the Sweet potato vines and Solanum diets. Eggplant wastes were the least (P < 0.05) preferred. On average the goats spent 5% of their 8-hour time eating eggplant wastes, 34% on sweet potato vines and 36% on elephant grass. Growth performance and N retention were low due to the low intake of feed, especially eggplant wastes.     

Effect of NDF/undegradable crude protein ratio on in vivo digestibility, particle passage rate in riverine buffaloes compared with sheep

In vivo digestibility (eight animals) and solid particles passage rate measured by faecal Cr (four animals fistulated at the rumen) were determined on riverine buffalo bulls and Delle Langhe rams, given four diets at maintenance level (50 g/kg M^0.75 per day of dry matter), according to a Latin square design, composed of a factorial combination of high and low NDF and of high and low protein undegradability. The diets were: L-30 = low NDF (530.0 g/kg DM), low undegradability of protein (29.6%, CP = 138.0 g/kg DM); L-40 = low NDF (537.0 g/kg DM), high undegradability of protein (41.0%, CP = 139.0 g/kg DM); H-30 = high NDF (583.0 g/kg DM), low undegradability of protein (28.3%, CP = 128.0 g/kg DM); H-40 = high NDF (NDF = 580.0 g/kg DM), high undegradability of protein (40.0%, CP = 128.0 g/kg DM). The digestibility of organic matter (66.68% vs. 64.32%, P < 0.05) and of the other analytical fractions (NSC, NDF, cellulose and hemicelluloses) was significantly higher in buffaloes with the exception of that of crude protein which was similar for the two species. Considering the diets within the species, the increased undegradable protein in the small intestine produces different effects: in the buffalo, it does not positively influence the digestibility of NSC but does increase that of cellulose, on the other hand in sheep it influences the digestibility of NSC. The post-ruminal digestibility of the undegraded protein, both in buffalo and sheep, is higher than that from protein of microbial origin. The passage rate of the marker of the solid particles, through the first compartment, k₁ (2.86% h^− 1 and 2.54% h^− 1 for the buffalo and the sheep) and through the entire intestinal tract, MRT (57.50 and 58.88 h for the buffalo and the sheep) does not show significant differences in the two species. The passage rate of the marker of the solid particles in buffalo rumen, at variance with the structural carbohydrates of the diet, is more variable compared with that of the sheep.     

Effect of resistant starch on the intestinal health of old dogs: fermentation products and histological features of the intestinal mucosa

The effects of resistant starch (RS) intake on nutrient digestibility, microbial fermentation products, faecal IgA, faecal pH, and histological features of the intestinal mucosa of old dogs were evaluated. The same formulation was extruded in two different conditions: one to obtain elevated starch cooking degree with low RS content (0.21%) and the other lower starch cooking with high RS content (1.46%). Eight geriatric Beagles (11.5 ± 0.38 years old) were fed each diet for 61 days in a crossover design. Food intake, nutrient digestibility, fermentation products, faecal pH, and faecal IgA were examined via variance analysis. Histological results of intestinal biopsies were assessed via Wilcoxon test for paired data. The morphometric characteristics of large intestine crypts were evaluated via paired t tests (p < .05). Protein, fat, and energy digestibilities were higher for the low‐RS diet (p < .05). Dogs receiving the high‐RS diet had lower faecal pH and higher values for propionate, butyrate, total volatile fatty acids, and lactate (p < .05). No differences between diets were found in the histological parameters of the gut mucosa, and only a tendency for deeper crypts in the descending colon was observed for dogs fed the high‐RS diet (p = .083). The intake of a corn‐based kibble diet manufactured with coarse ground raw material and low starch gelatinization to obtain 1.4% of RS affected microbial fermentation products and faecal pH and tended to increase crypt depth in the descending colon of old dogs.     

The use of n-alkanes to estimate diet composition of ruminants grazing on species diverse plant communities — Effect of feeding selectivity on diet composition estimates

The present study aimed to evaluate the effect of feeding selectivity (FS) within a dietary group comprising plant species with similar alkane profile, on the estimates of diet composition of goats, sheep and cows grazing on vegetation composed of gorse-heathland with areas of improved pastures. Plant species collected in the field study were grouped in four dietary groups according to cluster analysis: D1 (Lolium perenne, Pseudarrhenatherum longifolium and Agrostis capillaris), D2 (Calluna vulgaris, Erica cinerea, Erica umbellata, Erica australis), while Erica arborea (D3) and Ulex gallii (D4) remained as individual components due to their distinct n-alkane profiles. The application of different levels of feeding selectivity (0, 5, 15, 30, 60, 90 and 100%) to the graminaceous species included in D1 group affected significantly (P < 0.05) the diet composition estimates as a result of the modification of the alkane pattern of the dietary group used in the calculations. However, this effect was not so evident within all ranges of FS and when evaluated in the heather species of D2 group. When L. perenne and C. vulgaris were removed from D1 and D2 dietary groups and treated as individual components, there was a decrease in the FS effect on the diet composition estimates. The results obtained show that dietary groups formed by multivariate statistical analysis should be used carefully as they could be sensitive to feeding selectivity, with consequently large effects on the estimates of diet composition. This effect will depend on the similarity in the alkane profile of the plant species that composed the dietary group.     

Impact of grazing intensity on herbage intake, composition, and digestibility and on live weight gain of sheep on the Inner Mongolian steppe

High grazing pressure during the last decades caused severe ecological problems in the steppe of Inner Mongolia, China. The objective of the present study was to determine the effects of grazing intensity of sheep on herbage mass (HM) and intake, chemical composition and digestibility of herbage, and on live weight gain (LWG). A grazing experiment with six different grazing intensities (1.5, 3.0, 4.5, 6.0, 7.5, and 9.0 sheep/ha) was conducted in the growing season of 2005 in the Xilin River Basin. HM decreased from 1.5 t DM/ha at the lowest grazing intensity to 0.6 t DM/ha at the highest grazing intensity. NDF content of the herbage was high (> 700 g/kg DM) and relatively constant, whereas acid detergent lignin (ADL) content increased with grazing intensity and with proceeding grazing season. Digestibility of organic matter ingested (DOM) tended to decrease with grazing intensity as well as intake of organic matter (OMI) and of digestible organic matter (DOMI) per sheep (P = 0.090 and P = 0.065, respectively), whereas LWG per sheep decreased with increasing grazing intensity (P = 0.018). DOM and OMI were negatively related to ADL content. However, herbage intake and LWG per ha increased with grazing intensity (P < 0.001) and reached their maximum at 9 and 7.5 sheep per ha, respectively. This observation confirms the current farmers' practise of high grazing pressure ignoring long term grassland productivity and ecological problems. Therefore, the studies are continued to provide further information on long term effects. This study could show pronounced effects of grazing intensity on animal and grassland productivity and the suitability of the methods applied to measure intake and digestibility of herbage in a large scale grazing experiment with sheep.     

Effects of pistachio by‐products on digestibility,milk production,milk fatty acid profile and blood metabolites in Saanen dairy goats

The objective of this study was to investigate the effects of pistachio by‐products (PBP) on nutrient digestibility, blood metabolites and milk fatty acid (FA) profile in Saanen dairy goats. Nine multiparous lactating Saanen goats (on day 90 post‐partum, 45 ± 2/kg BW) were randomly assigned to a 3 × 3 Latin square design with three treatment diets: 1) control diet (alfalfa hay based), 2) 32% PBP and 3) 32% PBP + polyethylene glycol (PEG‐4000; 1 g/kg dry matter). Each period lasted 21 days, including 14 day for treatment adaptation and 7 day for data collection. Pistachio by‐products significantly decreased (p < 0.01) crude protein (CP) digestibility compared with the control diet (64.4% vs. 58.7%), but PEG addition did not differ for CP digestibility of goats fed 32% PBP + PEG and those fed the two other diets. The digestibility of NDF tended (p = 0.06) to decrease for goats fed PBP compared with those fed the control diet. Yields of milk and 4% fat‐corrected milk were not affected by dietary treatments. Compared with the control diet, PBP supplementation appreciably changed the proportions of almost all the milk FA measured; the main effects were decreases (p < 0.01) in FA from 8:0 to 16:0 and increases (p < 0.01) proportions of cis‐9, trans‐11 18:2 and trans‐11 18:1, monounsaturated FA, polyunsaturated FA and long‐chain FA. The saturated FA, short‐chain FA and medium‐chain FA proportions were lower (p < 0.01) in goats fed the two PBP supplemented diet than in those fed the control diet and PEG addition led to intermediate proportions of saturated FA, unsaturated and monounsaturated FA. Inclusion of PBP in the diet decreased (p < 0.01) plasma concentrations of glucose and urea nitrogen compared with the control diet. It was concluded that PBP can be used as forage in the diet of dairy goats without interfering with milk yield. Inclusion of 32% PBP in the diet of dairy goats had beneficial effects on milk FA profile but PEG addition to PBP did not contribute to enhance further milk FA profile.