Use of double-choice feeding to quantify feed ingredient preferences in pigs

Four experiments were conducted to evaluate the palatability of sorghum, maize, rye and lupine for pigs. Diets containing sorghum, maize, rye or lupine (test diets) were offered in a series of double choice tests against a reference diet. To prepare the reference diets, white broken rice in the experiments with cereals, and SBM-56 (a soy protein product low in anti-nutritional factors) in the experiment with lupine, were used as the cereal and the protein source of reference, respectively. Six test diets containing sorghum, maize or rye were prepared by replacing either 250 or 500 g kg^− 1 of broken rice from the reference diet. Similarly, two test diets containing lupine were prepared by replacing 75 or 150 g kg^− 1 of SBM-56 from the reference diet. Additionally, the pure ingredients were also evaluated against pure broken rice (sorghum, maize or rye) and pure SBM-56 (lupine). In each experiment, the corresponding ingredient was tested at two levels of inclusion and in pure form, using both newly weaned pigs and pigs at four weeks post-weaning. The palatability for each test diet expressed as % of preference was calculated as the percentage contribution of the test diet to total feed intake (test + reference diets). The preferences obtained ranged between 16 and 29% for sorghum, 16 and 35% for maize and 19 and 49% for rye. Except for rye at 500 g kg^− 1 (49%), preference values were significantly different from 50% which indicates a higher preference for the broken rice in the reference diet than for sorghum, maize and rye. Preference for lupine ranged between 39 and 56% and no difference in preference was observed between the lupine in the test diets and the SBM-56 in the reference diets. The dietary preferences could already be observed in the first days of experiment, and they did not change substantially thereafter. The levels of inclusion tested did not have an effect on preference for any of the ingredients. The age of the animals did not affect preference and the values obtained in newly weaned and post-weaned pigs were generally in good agreement. However the use of the older animals resulted in higher feed intakes and more accurate measurements. It is concluded that feedstuff palatability can be quantified with a double choice protocol using a reference diet. This should allow the formulation of feeds for weaning pigs taking into account the palatability of the ingredients, in addition to other nutritional criteria. Preference evaluation may become a useful tool to improve the palatability of the diets and facilitate piglets feed initiation at weaning.     

Influence of guanidination on apparent ileal digestibility of amino acids in pigs fed diets with soybean meal, rapeseed meal or peas as a protein source

The objective of this study was to determine the effect of guanidination, the conversion of dietary lysine to homoarginine, on the apparent ileal digestibilities (AID) of amino acids (AA) from 3 protein sources in diets for pigs. Six barrows, initial body weight of 18 ± 1.5 kg, fitted with a simple T-cannula at the distal ileum, were fed one of three corn starch-based diets that contained 18% crude protein (CP) from soybean meal, rapeseed meal or peas for an experimental period of 10 d according to a repeated 3 × 3 Latin square design. On d 9 of each experimental period, the pigs were fed one meal of the guanidinated test meals, which corresponded to their respective diets. In the test meals, 50% of the protein source in each diet was replaced, on an equal weight basis, with a guanidinated source. Guanidination increased the content of CP by 190, 116 and 28 g kg^− 1 for soybean meal, rapeseed meal and peas, respectively. With the exception of lysine, the AID of CP and AA were 2.2 to 8.2 percentage units (pu) higher in the test meal than in the soybean meal diet. Other than arginine and isoleucine, the differences were significant (P < 0.05) for all indispensable AA. With the exception of lysine, the AID of CP and AA were 3.8 to 11.9 pu higher in the test meal than in the diet with peas. The differences were significant (P < 0.05) for all indispensable AA. Other than lysine, glycine and proline, the AID of CP and AA were slightly higher, 0.1 to 4.3 pu, in the test meal than in the rapeseed meal diet. Of the indispensable AA, the differences were significant (P < 0.05) for arginine, leucine and phenylalanine. The AID of lysine was 10.9 pu lower (P < 0.05) in the test meal than in the rapeseed meal diet, 61.5 vs. 72.4%, indicating that guanidination of rapeseed meal was not uniform and random. The increase in the AID of CP and AA after guanidination may result from solubilisation of protein and degradation of antinutritional factors such as fiber, trypsin inhibitors and tannins.     

Influence of sow dietary fatty acid composition on the behaviour of the piglets

Polyunsaturated fatty acids (PUFA) are essential for the development of the nervous system in animals, and increased concentration of n−3 PUFA in maternal diet improves the cognitive development of mammalian foetuses. In this study the effect of maternal diet fatty acid composition in pigs on the development of the central nervous system, monitored as behaviour of piglets, was investigated using three behavioural tests: recognition of the mother's faeces, back test, and hidden door test.Twenty-seven multiparous Yorkshire sows were split into four groups and fed diets with different content of fat and PUFA throughout pregnancy and lactation. LF (n = 6) was fed a standard diet, HFS (n = 4) a high fat and low PUFA diet, HFO (n = 7) a high n−6 PUFA diet, and HFL (n = 10) a high n−3 PUFA diet.Three behavioural tests were performed on 5–7 randomly chosen piglets per litter (n = 167). Recognition of the mother's faeces was tested in a maze two days after birth. Back test was performed twice (2–4 d and 4 w) and a hidden door test was performed at 4 w. In addition, the brain content of docosahexaenoic acid (22:6 n−3, DHA) of the newborn piglets was determined in treatment groups. Data from the tests were analysed with linear mixed models for each of the tests.Piglets from HFL treatment had significantly higher content of DHA (P < 0.001) and the ratio of n−6/n−3 PUFA was significantly lower in brain tissue (P < 0.001), compared to piglets from the other treatments. In parity 3, means for recognition for mother's faeces were for diets LF, HFS, HFO and HFL; 22.2, 37.0, 26.4 and 18.0%, respectively (P < 0.05), but no other significant effect of diet was found. Piglets in HFS treatment had the shortest latency to make escape attempts and HFO piglets the longest latency in the back test (P = 0.030). No significant effect of sow diet was found on piglet performance in the hidden door test, but intermediate piglets weighing 1410–1619 g had a lower probability of success in hidden door test than piglets weighing < 1410 g (P = 0.028), and ≥ 1875 g (P = 0.027), respectively.It was found that sow diet influenced the DHA content in the piglet brains, but there was no clear effect of sow diet on piglet behaviour. In order to draw any conclusions about possible enhancements of the behavioural development of the piglet more studies need to be performed.     

Standardized ileal digestibility of proteins and amino acids in sesame expeller and soya bean meal in weaning piglets

Apparent ileal digestibility (AID) of diets containing sesame expeller (SE) and soya bean meal (SBM) was determined using 15 piglets (Genetiporc^®), weaned at 17 ± 0.4 days with average body weight of 6.4 ± 0.7 kg (Fertilis 20 × G Performance, Genetiporc^®, PIC México, Querétaro, México). Piglets were randomly assigned to three treatments: (i) a reference diet with casein as the sole protein source; (ii) a mixed diet of casein–SE; and (iii) a mixed diet of casein–SBM. The chemical composition of SE and SBM was determined, and AID and standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AAs) were determined for each protein source. SE contained greater quantities of ether extract, neutral detergent fibre, phytic acid, methionine and arginine than SBM. Lysine and proline contents and trypsin inhibitor activity were higher in SBM than in SE. The AID and SID of CP and AA (except for lysine and proline) were similar in SE and SBM. The AID of lysine and proline was higher in SBM than in SE (p < 0.05), and the SID of proline was higher in SE than in SBM (p < 0.05). These findings indicate that SE is an appropriate alternative protein source for early weaned pigs.     

Estimation of endogenous protein and amino acid ileal losses in weaned piglets by regression analysis using diets with graded levels of casein

Background

Many studies have investigated endogenous loss of proteins and amino acids (AAs) at the ileal level in growing pigs. However, only a few studies have researched this subject in piglets. Knowledge regarding AA ileal digestibility in piglets would be helpful during the formulation of diets for weaning piglets, rather than just using coefficients obtained in growing pigs. Therefore, in this study, we sought to estimate endogenous protein and AA ileal losses in piglets. Furthermore, apparent and true ileal digestibility (AID and TID) of protein and AAs from casein were measured.

Results

The average flow of protein was 20.8 g/kg of dry matter intake (DMI). Basal protein loss, as estimated by regression, was 16.9 g/kg DMI. Glutamic acid, arginine, and aspartic acid (2.2, 1.4, and 1.2 g/kg DMI, respectively) were the AAs for which greater losses were seen. The AID of protein and AAs increased as the protein level in the diet increased. A higher increment in AID was observed between diets with 80 and160 g CP/kg of feed; this finding was mainly attributable to increases in glycine and arginine (46.1% and 18%, respectively). The TID of protein was 97.8, and the TID of AAs varied from 93.9 for histidine to 100.2 for phenylalanine.

Conclusions

The basal endogenous protein loss in piglets was 16.9 g/kg DMI. Endogenous protein was rich in glutamic acid, aspartic acid, and arginine, which represented 32.7% of endogenous protein loss in weaning piglets. The TID of casein was high and varied from 93.0 for histidine to 100.2 for phenylalanine.     

Effects of intermittent suckling on the performance and digestive efficiency of Iberian piglets weaned at 35 days of age

During two consecutive replicates Iberian sows (n = 20) were subjected either to a conventional lactation (C) or intermittent suckling (IS). Piglets in the C treatment had free access to the dam. Piglets on IS treatment were separated from the sow during 6 h on days 29 and 30, 8 h on days 31 and 32, and 10 h on days 33 and 34. Litters on both treatments were weaned at 35 days of age and offered a starter diet until day 60 of age. The apparent digestibility (ApD) of nutrients and gross energy (GE) of the post-weaning diet was measured using Cr₂O₃ as external indigestible marker. Litters on IS tended to increase solid feed intake during the milk restriction (125 ± 12 vs. 70 ± 19 g piglet^− 1 day^− 1; P = 0.08). Feed intake was improved by IS during the second week post-weaning (676 ± 17 vs. 497 ± 12 g piglet^− 1 day^− 1, P < 0.01), but differences were totally offset after the 7th week of age. Differences in average growth rate of litters on C and IS treatments did not attain statistical significance during the period of restriction and in the first week post-weaning. Litters on IS showed increased growth rate during the second week post-weaning (422 ± 31 vs. 289 ± 33 g piglet^− 1 day^− 1; P = 0.01), but slower daily gains from the 3rd week post-weaning to 60 day of age than litters on C treatment (371 ± 14 vs. 432 ± 15 g piglet^− 1 day^− 1; P < 0.05). Nevertheless, neither at weaning nor at 60 days of age average body weight of piglets differed between treatments (7.71 ± 0.31 vs. 7.94 ± 0.30 kg for C and IS, at 35 days of age, 15.62 ± 0.65 vs. 16.20 ± 0.62 kg, at day 60). The apparent digestibility of nutrients of the starter diet offered after weaning remained unaffected by the treatment, except for a trend for higher ApD of GE for the piglets on IS treatment (P = 0.08). ApD for CP and GE was 78.1 ± 0.6 and 78.8 ± 0.3%, respectively. No significant differences in the proportions of total viscera and gastrointestinal tract to empty body weight (EBW) were observed between C and IS piglets at weaning and 60 d of age. In conclusion, the increase in feed intake observed prior and early after weaning as a consequence of intermittent suckling during the last week of 35 d lactation had no effect on nutrient digestibility measured at two weeks after weaning and failed on improving Iberian piglet performance.     

Characteristic of duodenal myoelectric activity in relation to food in piglets during the 3rd and 4th week of life

The relationship between duodenal myoelectric activity and liquid food intake was investigated in eight conscious piglets with bipolar electrodes implanted on the wall of the duodenum. Piglets were fed with commercial milk formula and the effects of volume and feed dry matter intake on duodenal myoelectric activity were measured by means of an analog–digital recording system.The cyclic pattern of duodenal myoelectric activity, i.e. the migrating myoelectric complex (MMC), was preserved when piglets received small meals at regular intervals. The duration of the whole MMC cycle, as well as the duration of phase II of the MMC, were only weakly correlated (r = 0.2, P < 0.05 for both parameters, respectively) to the amount of ingested food. However, the increase of the amount of feed dry matter intake of a meal from 2.1 to 4.5 g kg^− 1 of live body mass (LBM) as well as an increase of volume of a meal from 13 to 26 ml kg^− 1 LBM significantly increased the duration of the MMC cycles (P < 0.05) due to the elongation of phase II of the MMC (P < 0.05).The present study shows that in piglets fed with a liquid diet the upper gut motility response to food is similar to that previously observed in adult animals.     

Effects of maturity stage and feeding strategy of whole crop barley silage on intake, digestibility and milk production in dairy cows

Five diets containing concentrate, grass silage and whole crop barley silage (WCBS) harvested at different maturity stages were fed to 15 multiparous dairy cows in an incomplete change-over design over three periods. Three diets contained 10.7 kg dry matter (DM) concentrate, 4 kg DM grass silage, and ad libitum access to WCBS harvested at either the heading stage (B1), the early milk stage (B2) or the early dough stage (B3) of maturity. The other two diets contained 10.7 kg DM concentrate, whereas grass silage and WCBS at heading were mixed at two different ratios with a DM content of WCBS of either 0.30 (M1) or 0.70 (M2), and the mixtures were fed ad libitum. Intakes of DM (kg day^− 1: B1 = 21.0, B2 = 20.6 and B3 = 20.0) and neutral detergent fibre (NDF; kg day^− 1: B1 = 7.0, B2 = 6.4 and B3 = 6.3) decreased, whereas starch intake increased (kg day^− 1: B1 = 3.1, B2 = 3.5 and B3 = 4.0) with increasing maturity at harvest. The apparent organic matter (OM) digestibility (g kg^− 1: B1 = 800, B2 = 774 and B3 = 729) decreased with increasing maturity stage, and consequently so did the digestible OM intake. Milk (kg day^− 1: B1 = 27.2, B2 = 26.1 and B3 = 25.9) and energy corrected milk (ECM; kg day^− 1: B1 = 31.0, B2 = 29.4 and B3 = 28.2) yields, and protein concentration (g kg^− 1: B1 = 37.1, B2 = 36.4 and B3 = 36.0) decreased with increasing maturity stage of the WCBS. When cows were fed diet B3 the milk fat concentration decreased (46.4 g kg^− 1) compared to diets B1 (49.3 g kg^− 1) and B2 (49.4 g kg^− 1). The difference in ECM yield between diets B1 and B3 was due to a combined effect of lower milk yield, and lower protein and fat concentrations. This was caused by the higher starch and lower NDF intakes with diet B3, which decreased the milk fat concentration. Moreover, a lower energy intake of diet B3 due to lower OM digestibility decreased milk protein concentration and milk yield. Mixing WCBS at the heading stage with grass silage (M2) decreased digestibility, compared to feeding the forages separately (B1). However, the differences were small and may be a result of soil contamination at harvest of some of the silages, which made the method with using incomplete faecal collection and internal marker acid insoluble ash less reliable. Including WCBS at the heading stage at 0.30 or 0.70 of forage DM did not affect DM intake or diet digestibility, probably because the grass silage in the study was very similar in energy content to the WCBS harvested at heading.     

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.     

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.     

Rumen degradation characteristics of sweet potato foliage and performance by local and crossbred calves fed milk and foliage from three cultivars

The study investigated rumen dry matter (DM) degradability characteristics in a completely randomized design and the effects of milk, sweet potato foliage (SPF) from three cultivars (A = TIS-87/0087; B = TIS-8164; C = TIS-2532.OP.1.13), dried brewers' grains (DBG) and cottonseed meal (CSM) as supplements to Panicum maximum (Panicum) for pre-weaned calves in randomized complete block designs. Diet 1 = milk + SPF-A foliage + Panicum, Diet 2 = milk + SPF-B foliage + Panicum, Diet 3 = milk + SPF-C foliage + Panicum, and Diet 4 = milk + DBG & CSM + Panicum (as control). Dry matter (130 ± 0.4 to 864 ± 3.9 g kg^− 1), ash (54 ± 4.2 to 173 ± 2.8 g kg^− 1 DM), OM (827 ± 4.2 to 946 ± 5.7 g kg^− 1 DM), N (7.4 ± 0.6 to 38.6 ± 1.4 g kg^− 1 DM), and NDF (439 ± 1.4 to 774 ± 8.5 g kg^− 1 DM) contents were highly significant (P < 0.01). In Trial I, 16 pre-weaned calves were used over 70 d with milk intake (34.8 ± 4.4 ml kg W^− 0.75 d^− 1), Panicum DMI (22.3 ± 2.77 g kg W^− 0.75 d^− 1), total DMI (35.7 ± 2.83 g kg W^− 0.75 d^− 1), and LWG (198 ± 44.6 g d^− 1) not significantly different (P > 0.05). Supplement DMI varied (P < 0.05) from 11.6 g kg W^− 0.75 d^− 1 in Diet 3 to 16.6 g kg W^− 0.75 d^− 1 in Diet 4. In Trial II, 16 pre-weaned local and crossbred calves were involved over 77 d with initial age of calves, Panicum intake, metabolic DMI, and LWG similar (P > 0.05) among crosses. Birthweight varied (P < 0.05) from 17.3 kg for N'Dama × Jersey crosses to 21.2 kg for White Fulani × Brown Swiss crosses. Supplement and total DMI ranged (P < 0.05) from 172 to 483 g d^− 1 for N'Dama × Jersey crosses to 233 and 674 g d^− 1 for non-inseminate or purebred calves, respectively. The LWG in the White Fulani × Brown Swiss and the N'Dama × Jersey calves were respectively 30% and 24% better, though not significantly, than purebred calves. In Trial III, rumen DM degradability characteristics of feeds in three N'Dama steers showed no significant differences (P > 0.05) in slowly degradable fraction (b) and rate of degradation of b (c). Soluble fraction (a), 48-h degradation, potential degradability (PD) and effective degradability (ED) varied significantly (P < 0.05) and were lowest in Panicum, but similar for foliage among the three sweet potato cultivars. Panicum fodder showed improvements in degradation characteristics with supplementation.     

Additivity of values for apparent and standardized ileal digestibility of amino acids in mixed diets fed to growing pigs

The objective of this experiment was to determine whether the digestibility of CP and AA in a mixed diet fed to growing pigs is better predicted when based on standardized ileal digestibility coefficients (SID) or apparent ileal digestibility coefficients (AID). Eight growing pigs (initial BW = 92.1 +/- 3.19 kg) were surgically equipped with a T-cannula in the distal ileum and arranged in an 8 x 8 Latin square design with eight diets and eight periods. Three of the diets contained corn, soybean meal (SBM), or canola meal (CM) as the sole source of CP and AA. Four mixed diets also were formulated using corn and soybean meal (CS); corn and canola meal (CCM); soybean meal and canola meal (SCM); or corn, soybean meal, and canola meal (CSCM). A N-free diet was used to measure the basal ileal endogenous losses (IAAend) of CP and AA. Pigs were fed each of the eight diets during one 7-d period, and ileal digesta were collected during two 10-h periods on d 6 and 7. The AID values were calculated for CP and AA in all diets, except the N-free diet. By correcting the AID for IAAend, the SID for CP and AA in each of the seven protein-containing diets were calculated. As expected, the AID for CP and the majority of AA were greater in SBM than in corn and CM (P < 0.05); however, the SID for CP and most AA did not differ between corn and SBM. For the majority of the AA, SID were less (P < 0.05) in CM than in the other two ingredients. Using the AID and the SID that were measured for CP and AA in corn, SBM, and CM, the AID and the SID in the four mixed diets were predicted and compared with the measured values for these diets. For the three mixed diets containing corn, the measured AID for CP and most AA were greater (P < 0.05) than the predicted AID, but with a few exceptions, no differences between predicted and measured values for SID were observed. For the diet based on SCM, there were no differences between predicted and measured values regardless of the procedure used, except for the AID of Ser. The results of this experiment demonstrate that the digestibility coefficients for a mixed diet containing low-protein feed ingredients, such as corn, are more accurately predicted using SID than AID.     

Effects of body condition score at calving and feeding various types of concentrate supplements to grazing dairy cows on early lactation performance

The objective of the experiment reported here was to establish the effect of canola meal supplements of different protein degradability on the performance of grazing dairy cows with different body condition scores (BCS) in early lactation, and to compare this with feeding a cereal grain supplement instead. The experiment included a total of 72 cows in six treatments in a 2 ^* 3 factorial design, incorporating two BCS at calving (4.1 and 5.6 units on an 8-point scale), and three early lactation pelleted supplements. The three pelleted supplements were 100% wheat (wheat supplement), 50% wheat and 50% untreated mechanically extracted canola meal (a rumen degradable protein supplement), and 50% wheat and 50% canola meal that had been subjected to additional heat and pressure (a rumen undegradable protein supplement). It was hypothesised that fat cows would perform best with the treated canola meal supplement, which provided most rumen undegradable protein, whereas the type of protein would not be important for thin cows, and neither would the type of supplemental energy. Cows grazed pasture after calving at a daily pasture allowance of 35–40 kg DM/cow and were offered 6 kg concentrates each day. Cows were fed these diets for 92 days on average, from calving until three weeks into the mating period. Both canola meal-based supplements resulted in higher (P < 0.05) daily milk production than the wheat supplement (33.3 and 34.0 v. 30.5 kg/cow) in both thin and fat cows. Body condition score at calving positively (P < 0.05) affected average milk yield (31.6 v. 33.7 kg/cow), however, there was a time × BCS × supplement interaction whereby the fatter cows benefited from the use of either of the canola meal supplements for a longer period than did the thin cows. Average milk fat concentrations were greater (P < 0.05) where the canola meal supplements were fed (39.3 and 39.6 v. 35.6 g/kg), and in fat cows relative to thin cows (40.0 v. 36.3 g/kg). Serum urea concentrations were significantly (P < 0.05) lower in cows fed wheat than in those fed either of the canola meal supplements (3.1 v. 4.3 and 4.2 mmol/L). Serum β-hydroxybutyrate concentrations were lowest (P < 0.05) where wheat pellets were fed, and highest (P < 0.05) where treated canola meal pellets were fed, and plasma glucose concentrations were highest with wheat and lowest with the treated canola meal pellets. Thus, the hypothesis was not supported by the results of this experiment.     

Effect of feeding forest foliages, rice straw and concentrate-based total mixed ration on nutrient utilization and growth in mithun (Bos frontalis)

The study aimed to evaluate the effect of feeding Borrena hirticulata (BH), Ficus hirta (FH), rice straw (RS) and concentrate-based total mixed ration (TMR) on nutrient utilization, rumen fermentation and growth in mithun. Growing male mithun calves were randomly allotted to 2 feeding groups (6 in each), TMR₁ and TMR₂. The TMRs consisted of RS 300 g kg^− 1, concentrate 400 g kg^− 1 and BH 300 g kg^− 1 (TMR₁) or FH 300 g kg^− 1 (TMR₂) on a dry matter (DM) basis. Both TMRs were fed ad libitum to the animals for 121 d and a digestibility study was conducted during the last 7 d of the experiment. To assess rumen fermentation, rumen fluid was collected at 2 h interval for 24 h. Apparent digestibility of DM, crude protein (CP) and crude fibre (CF) did not differ significantly between the TMRs. Nevertheless, apparent digestibility of ether extract was found to be significantly (P < 0.01) greater in TMR₂ (0.59) compared to TMR₁ (0.54). Body weight gain (BWG; g d^− 1), DM intake (kg d^− 1), CP intake (g d^− 1) and feed efficiency (kg feed kg^− 1 gain) were found to be significantly (P < 0.05) greater in TMR₁ (548, 5.14, 713 and 9.28) compared to TMR₂ (496, 4.91, 703 and 10.03). An insignificant positive association (r = 0.35) between DM intake and BWG, but a significant (P < 0.01) positive association (r = 0.74) between CP intake and BWG were evident. Rumen pH (5.71 to 7.18) and ammonia-nitrogen (8.0 to 25.0 mg/dl) did not differ significantly between the TMRs, but differed significantly (P < 0.01) at different h post-feeding. In contrast, rumen total volatile fatty acid (42 to 105 mM) and total nitrogen (40.4 to 90.3 mg/dl) differed significantly (P < 0.05) between the TMRs and at different h post-feeding. The study revealed that BH, FH, RS and concentrate-based TMRs may be fed to mithun for satisfactory growth.     

Can outdoor rearing and increased weaning age compensate for the removal of in-feed antibiotic growth promoters and zinc oxide?

This experiment determined whether delayed weaning and outdoor rearing could compensate for the removal of antimicrobials from piglet diets. One hundred and sixty litters of Large White (75%) × Landrace (25%) pigs on the same unit were reared either indoors (In) or outdoors (Out) and weaned at either 4 or 6 weeks of age into flat deck accommodation onto diets supplemented with either no antibiotic growth promoters and no zinc oxide (Un) or 40 mg avilamycin and 3.1 g zinc oxide/kg diet (S). Piglet performance was monitored to 8 weeks of age. A proportion of litters (25%) were sampled to investigate the effect of the different treatments on gut development. Mortality was higher in the first 24 h of life for Out piglets which subsequently grew faster to weaning. This was not simply due to smaller litter size as total litter gain was higher in outdoor litters. All piglets responded positively to antimicrobial supplementation post weaning regardless of rearing environment and weaning age and this was the biggest influence on post weaning performance. Outdoor piglets grew faster than indoor piglets post weaning (295 versus 242 ± 8.6 g/pig/day for the first 2 weeks post weaning, P < 0.001) and over the same period 6 week weaned piglets grew faster than 4 week weaned (324 versus 213 ± 8.6 g/pig/day, P < 0.001), however, when compared at similar age, 6 week weaning was detrimental to piglet growth with average daily gain (adg) from 4 to 8 weeks of age 310 g/pig/day versus 329 for 4 week weaned piglets (P = 0.001). At 8 weeks of age the outdoor 6 week weaned unsupplemented piglets had similar average weight to the indoor 4 week weaned supplemented piglets indicating the potential of this combination to counteract the need for antimicrobials, however the benefit was due to enhanced weaning weight not to improved post weaning performance.     

Effects of a dietary supplement of DHA-rich marine algae on Italian heavy pig production parameters

To evaluate the effects of dietary supplementation with a marine algae product (MA) containing a high level of docosahexaenoic acid (DHA) on heavy pig production performances (including meat and subcutaneous fat quality), a trial was conducted on sixty Landrace × Large White barrows with a starting average body weight (BW) of 118 kg. Pigs were allocated to four experimental groups: a control group (A) fed a maize/soybean diet and three treatment groups in which MA was added at 2.5 g kg^− 1 over the last 8 weeks prior to slaughtering (group B) or at 5 and 2.5 g kg^− 1 over the last 4 weeks prior to slaughtering (groups C and D, respectively). Vitamin E was added at 12.5 mg kg^− 1 in the diets for groups B and D and at 25 mg kg^− 1 in the diet of group C. The four diets were formulated so as to supply the same amount of nutrients, with exception of vitamin E. Pigs were fed at a rate of 9% of their metabolic BW (BW^0.75) up to a maximum of 2.9 kg of dry matter per pig per day. Pigs were slaughtered at about 160 kg BW. The dietary treatment did not affect either the growth or slaughtering parameters of pigs. No significant differences were observed with respect to pH values, meat colour, loin composition and the iodine number of subcutaneous fat. Pigs on MA diets showed a significant (P < 0.01) improvement in DHA levels both in loin and in subcutaneous fat. No significant differences in relative fatty acid composition were observed between pigs receiving the MA supplement at the lower level (2.5 g kg^− 1) over an 8-week period (group B) and pigs receiving the higher MA supplement (5.0 g kg^− 1) over a 4-week period prior to slaughter (group C).     

Estimation of endogenous protein and amino acid ileal losses in weaned piglets by regression analysis using diets with graded levels of casein

Background： Many studies have investigated endogenous loss of proteins and amino acids （AAs） at the ileal level in growing pigs. However, only a few studies have researched this subject in piglets. Knowledge regarding AA ileal digestibility in piglets would be helpful during the formulation of diets for weaning piglets, rather than just using coefficients obtained in growing pigs. Therefore, in this study, we sought to estimate endogenous protein and AA ileal losses in piglets. Furthermore, apparent and true ileal digestibility （AID and TID） of protein and AAs from casein were measured. Results： The average flow of protein was 20.8 g/kg of dry matter intake （DMI）. Basal protein loss, as estimated by regression, was 16.9 g/kg DMI. Glutamic acid, arginine, and aspartic acid （2.2, 1.4, and 1.2 g/kg DMI, respectively） were the AAs for which greater losses were seen. The AID of protein and AAs increased as the protein level in the diet increased. A higher increment in AID was observed between diets with 80 and160 g CP/kg of feed; this finding was mainly attributable to increases in glycine and arginine （46.1% and 18%, respectively）. The TID of protein was 97.8, and the TID of AAs varied from 93.9 for histidine to 100.2 for phenylalanine. Conclusions： The basal endogenous protein loss in piglets was 16.9 g/kg DMI. Endogenous protein was rich in glutamic acid, aspartic acid, and arginine, which represented 32.7% of endogenous protein loss in weaning piglets. The TID of casein was high and varied from 93.0 for histidine to 100.2 for phenylalanine.     

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.     

Effect of virginiamycin and monensin supplementation on performance of multiparous Holstein cows

This study was conducted to determine the effects of monensin or virginiamycin, or both on the performance of and some energy balance parameters in Holstein cows. Forty multiparous Holstein cows were used in a randomized complete block design experiment. The basal diet was a total mixed ration based on lucerne hay (38% of DM) and ground maize (34% of DM). The experimental treatments were (1) control diet (C); (2) control diet plus 15 ppm of monensin (M); (3) control diet plus 20 ppm of virginiamycin (V), and control plus M (15 ppm) plus V (20 ppm). Cows received 8 kg/d (as fed) of the experimental diets plus ad libitum Eragrostis curvula hay from 3 weeks prepartum and only the experimental diets from calving until 60 days postpartum. Cows were milked twice daily. Dry matter intake did not differ between treatments, but energy corrected milk production was increased (P < 0.10) by supplementing V + M (43.3 kg/d) when compared to treatments M (36.9 kg/d) and V (37.9 kg/d). Change in body weight tended (P = 0.11) to be lower for cows supplemented with V + M (− 8.1 kg/60 d) when compared to cows receiving the control diet (− 34.2 kg/60 d). Both treatments M and V respectively, decreased blood BHBA and treatment M increased blood glucose when compared to the control diet (P < 0.10). Results suggest a complimentary effect between the two additives monensin and virginiamycin when supplemented to early lactation cows.     

Nutrient digestibility of extruded canola meal in ileal-cannulated growing pigs and effects of its feeding on diet nutrient digestibility and growth performance in weaned pigs

Canola meal (CM) contains less crude protein (CP) and more fiber and anti-nutritional factors such as glucosinolates than soybean meal (SBM) and consequently has a lower nutrient digestibility. Therefore, processing strategies that may increase the feeding value of CM warrant study. In two experiments, the effects of extrusion of Brassica napus CM on apparent (AID) and standardized ileal digestibility (SID) of amino acids (AA), apparent total tract digestibility (ATTD) of gross energy (GE) in growing pigs, and growth performance and diet digestibility in weaned pigs were assessed. Solvent-extracted CM was extruded using a single-screw extruder at three screw speeds: 250 (CM-250), 350 (CM-350), or 450 (CM-450) rpm. In exp. 1, in a double 4 × 4 Latin square, eight ileal-cannulated barrows (initial body weight [BW], 68.1 kg) were fed corn starch-based diets containing 50% CM or extruded CM. The CM sample contained 43.2% CP, 33.2% total dietary fiber (TDF), and 8.9 µmol of total glucosinolates/g on a dry matter (DM) basis. Extrusion increased (P < 0.05) the AID of CP, reduced (P < 0.05) apparent hindgut fermentation of CP, and decreased (P < 0.05) predicted net energy (NE) value of diets. Extrusion increased diet AID and CM SID of most indispensable AA by 3.1 to 5.3%-units. In exp. 2, 200 weaned pigs (initial BW, 8.3 kg) were fed diets containing 20% SBM, CM, or extruded CM starting 2 wk postweaning for 3 wk. The CM sample contained 42.7% CP, 28.3% TDF, and 5.3 µmol total glucosinolates/g DM. Wheat-based diets provided 2.3 Mcal NE/kg and 5.1 g SID Lys/Mcal NE. Dietary inclusion of extruded CM replacing SBM decreased (P < 0.05) diet ATTD of DM, GE and CP, and DE value. Average daily feed intake, average daily gain (ADG), and gain:feed (G:F) of pigs did not differ between extruded CM and SBM diets and were not affected by extrusion, but increasing extruder screw speed linearly increased (P < 0.05) ADG for day 1 to 7 and G:F for the entire trial. In conclusion, extrusion increased diet AID and CM SID of AA but not DE and predicted NE values of CM. However, increasing extruder speed did not further increase the SID of most of the AA of CM in growing pigs. Dietary inclusion of 20% CM or extruded CM did not affect the growth performance in weaned pigs.