Novel encapsulated calcium butyrate supplement enhances on-farm dairy calf growth performance and body conformation in a pasture-based dairy production system

The effect of supplementing neonatal heifer calves with varying levels of ECAB on pre-weaning growth performance was investigated. Post-weaning growth was also measured, to determine any carry-over effect of pre-weaning supplementation of ECAB. Forty-eight heifer calves (7 ± 0.4 days old, average liveweight of 39.3 ± 5.3 kg) were utilized in a complete randomised experimental design, comprising 16 calves per pen, randomly allocated to one of the following three treatments: (1) Basal commercial calf starter mix without ECAB (Control); (2) control plus 4 kg/ton of ECAB (Low); and (3) control plus 6 kg/ton of ECAB (High). Calves were group-fed ad libitum for 77 days (11 weeks, pre-weaning period) with free choice access to water and 5.5 litres of milk per head per day through an automated feeder. Calves were weighed weekly during the pre-weaning period, after which all calves were then weaned onto the same ryegrass pasture as one group. At approximately 9 months of age, calves were weighed to estimate post-weaning body weight gain. During the pre-weaning period, average daily dry matter feed intake was similar for 4 kg/ton and 6 kg/ton calves (649 g versus 688 g, respectively) and both were greater than that of the control calves (382 g). Average daily gain (ADG) was significantly higher for 4 kg/ton calves compared to 6 kg/ton calves or control calves (0.83 ± 0.03 kg, 0.74 ± 0.03 kg and 0.71 ± 0.03 kg, respectively; p = 0.0001). Similarly, 4 kg/ton calves had significantly increased chest girth (95.9 ± 0.7 cm), withers height (88.9 ± 0.5 cm), body length (82.9 ± 0.6 cm), and body condition score (1.99 ± 0.12) compared to 6 kg/ton calves (93.4 ± 0.7 cm, 87.4 ± 0.7, 81.5 ± 0.6 cm, and 1.67 ± 0.10, respectively) or control calves (92.9 ± 0.7 cm, 88.2 ± 0.5 cm, 80.1 ± 0.6 cm, and 1.30 ± 0.08, respectively). There was significant treatment x week interaction for all pre-weaning growth parameters. Breed differences were detected but there was no treatment x breed interaction. Post-weaning, 4 kg/t calves and 6 kg/t calves had significantly higher ADG compared to control calves (0.80 ± 0.03 kg, 0.85 ± 0.03 kg versus 0.70 ± 0.03 kg, respectively; p = 0.0047). It is concluded that under the conditions of this study, supplementing heifer calves with ECAB during pre-weaning period resulted in improved growth performance and there appears to be a post-weaning carry-over effect

Effect of tannins on the nutritive value of tropical shrubs

Three studies were conducted to assess the effect of condensed tannins (CT) on the nutritive value (NV) of some tropical shrubs. The first study involved two experiments (Experiments la and lb). Experiment la was designed to investigate the nylon bag dry matter digestibility (NBDMD) of 12 tropical shrubs (10 legumes and 2 non-legumes) varying in their content of extractable (ECT) and bound (BCT) condensed tannin. Samples were finely-chopped (- 3 mm) and incubated as either fresh or after oven-drying at 65C for 48 hours in the rumen of 5 steers. The contents of nitrogen (N), neutral (NDF) and acid (ADF) detergent fibres, lignin, ECT by vanillin (ECTvan) and butanol-HC1 (ECTbut) assay methods, protein-bound (PCT) and fibre-bound (FCT) were measured and the relationship between these plant constituents and the NBDMD were determined. Experiment lb was undertaken to determine the effect of drying method of forage samples on the chemical and CT contents, and NBDMD of 6 shrub legumes. A further purpose was to determine the effect of drying method on the prediction of NBDMD from the chemical and CT constituents. Forage samples were either freeze-dried (FD) at -30C or oven-dried (OD) at 65C for 48 hours and then ground through a 1 mm screen before the analyses or nylon bag digestion. The second study was an investigation of the effect of preparation method of fresh forage samples on the NBDMD of two leguminous shrub species, Calliandra calothyrsus and Lysiloma watsonii. Preparation methods included: fresh material coarsely (Ti) or finely (T2) chopped immediately after harvest and inserted in the rumen of steers within 30 minutes of harvest and preparation of sample; fresh material finely chopped and held for 6 hours before incubation either, in the oven at 65C (T3), in a sealed plastic bag and refrigerated at about 4C (T4) or in shade (wilted) under room temperature (approx. 23C, T5); unchopped fresh material was sealed in a plastic bag and refrigerated for 6 hours before being finely-chopped and inserted in the rumen immediately after preparation (T6). All samples were incubated in the rumen of steers for 48 hours. In the third experiment the effect of the addition of polyethylene glycol (PEG) on in vitro dry matter digestibility (IVDMD) of freeze- (FD) and oven-dried (OD) samples of 4 shrub species was determined. Two in vitro techniques were used, the rumen-liquor-pepsin (RLP) and the pepsin-cellulase (PC) methods. Polyethylene glycol was added as a solution at 0, 80, 160, 320 or 640 mg/g DM of sample incubated. The results of the chemical analysis showed significant (P0.05). Oven-drying significantly (P0.05) for both the analysis and digestion study. The relationship between NBDMD and other chemical or CT component was not affected by drying. Preparation method of fresh forage significantly (P<0.001) affected NBDMD of both C. calothyrsus and L. watsonii. Coarse-chopping (- 15 mm) gave lower estimates of NBDMD compared to fine-chopping (- 3 mm). Holding freshly-chopped samples for 6 hours significantly (P<0.05) depressed NBDMD and this depression was related to temperature and was greatest in OD samples. In vitro dry matter digestibility differed significantly (P<0.001) between species, method of drying samples, the level of PEG and some of the interactions between these factors. Addition of PEG at 80-160 mg/g DM of sample significantly (P<0.05) improved IVDMD of the tannin-containing shrubs. Increasing the level of PEG beyond 160 mg up to 640 mg/g DM did not show any further improvement in IVDMD. Generally, the PC method gave significantly (P<0.05) higher IVDMD than the RLP method at all levels of PEG (62.77 vs. 54.14%, s.e.d. = 0.28). Similarly, FD samples were significantly (P<0.05) higher in IVDMD than OD samples (59.32 vs. 57.60% respectively, s.e.d. = 0.28). It was concluded from these studies that the composition of CT varied between assay technique and species. Also, the effect of CT on the NV of tanninferous tropical shrubs also varied between species. The variation in the effect of oven-drying on the chemical and CT contents and the digestibility of shrubs was attributed to the differences in the composition and nature of CT present in individual shrubs. It appears that the depressing effect of CT on digestibility was primarily due to the free or extractable form rather than the bound CT in the species studied. However, in addition to CT, other factors such as the fibre and lignin components of shrubs also affect digestibility. Method of preparation of fresh samples should be taken into consideration when conducting a chemical analysis or nylon bag digestibility study. Whenever possible, freshly-chopped forage materials should be used. Otherwise, fresh materials can be stored under low temperature (VC) prior to incubation in the rumen. Polyethylene glycol improved IVDMD irrespective of in vitro technique or drying method but the efficiency of PEG varied from one species to another since the nature and reactivity of CT vary between species. Polyethylene glycol was not able to overcome the depression in IVDMD associated with oven-drying probably due to the formation of some irreversible CT-protein complexes. The Pepsin-cellulase in vitro technique gave higher estimates of IVDMD than the RLP technique after 48 hours of incubation. More studies were suggested to further understand the anti-nutritional effects of CT, most especially in dried forages. Characterisation of tannins in plant materials should precede their quantitative determination. Also, more in vivo studies and feeding trials are recommended since in addition to digestibility and chemical composition, the NV of forage is a function of voluntary feed intake and the efficiency of conversion of digested nutrients to tissue gain and reproductive performance

Degummed crude canola oil supplementation affects fat depot melting points in purebred and first-cross Merino sheep

The objective of this study was to test the hypothesis that degummed crude canola oil (DCCO) will lower fat melting points (FMP) of both visceral and subcutaneous fats in lambs. Twenty-four lambs comprising purebred and first-cross Merino progeny from Dorset, White Suffolk and Merino sires mates to purebred Merino ewes were supplemented with varying levels of DCCO over a nine week period. The experimental treatment groups were: Control (1kg plain wheat-based pellets only), Medium (500g plain wheat-based pellets + 500g wheat-based pellets containing DCCO), and High (1kg wheat-based pellets containing DCCO at a concentration of 50ml/kg) supplementation levels. The flock comprised eight wether and ewe lambs per treatment. However, at the end of the trial, four Merino ewes were retained in the flock for breeding purposes, while the remaining twenty lambs were slaughtered in a commercial abattoir. Visceral fat samples were taken from the kidney region and subcutaneous fat samples from the Longissimus dorsi muscle. FMP was determined using temperature slip point methodology in the laboratory. DCCO had significant effects on the FMP of both subcutaneous (P 0.0002) and visceral (p<0.0001) fats, with the lowest FMP achieved at high levels of supplementation in both fat depots. Significant sire breed differences (p<0.0001) were also detected in which Dorset-sired progeny had the highest melting points in both fat depots. The results of this study indicate that within fat depots, DCCO supplementation produced softer fats with lower melting points, suggesting potentially healthier fats containing higher levels of unsaturated fatty acids

Genetic variation in intramuscular fat of prime lamb supplemented with varying concentrations of degummed crude canola oil

The main objective of this study was to quantify the intramuscular fat (IMF) content of Longissimus thoracis et lumborum, biceps femoris and triceps brachii muscles in genetically divergent lambs supplemented with varying levels of degummed crude canola oil (DCCO). Over a nine-week feeding trial, twenty-four first-cross prime lamb progeny from Merino, Dorset and White Suffolk rams mated with purebred Merino ewes under the same nutritional management we re supplemented with one of three levels of wheat-based pellets with or without DCCO. The experimental treatments included the Control (1kg of plain wheat-based pellets without DCCO/head/day on dry matter basis), High (1kg of wheat-based pellets containing 50ml of DCCO/kg/head/day on dry matter basis) and Medium (500g of Control + 500g of High wheat-based pellets/head/day on dry matter basis). All lambs had a three-week adjustment period and had ad libitum access to lucerne hay and water. After nine weeks of supplementation, all experimental lambs were slaughtered at a commercial abattoir with the exception of four purebred Merino ewes retained in the flock for breeding purposes. IMF content was analysed using a 2:1 vol/vol ratio of chloroform/methanol extraction and precipitated with 10% potassium chloride. IMF content varied significantly with the level of DCCO supplementation (p<0.0125) and muscle type (p<0.0001). There were also highly significant interactions between sire breed and level of DCCO supplementation (P<0.0016), and muscle type and sex (P<0.0003) in IMF content. Prime lambs in the Control and Medium level of DCCO supplementation had the most IMF (3.18±0.12 and 3.28±0.14%, respectively) and the High treatment had the least (2.96±0.10%), suggesting a decrease in IMF as supplementation levels with DCCO increased. The Longissimus thoracis et lumborum had more IMF (3.69±0.11%) than the biceps femoris (2.87±0.11%)) and triceps brachii (2.90±0.12%) muscles. It was also evident that in ewes, the biceps femoris had the least IMF (2.4%) compared with Longissimus thoracis et lumborum (3.6%). This result indicates that supplementation of prime lambs with DCCO can be used as a management tool to vary the level of IMF content to suit different market specifications dictated by meat consumers. Whereas in themselves, sex and sire breed of lambs used in this study were not the primary drivers of IMF deposition, our results demonstrate that sheep farmers can modify their nutritional management and breed combinations by effectively utilizing appropriate sire breed and supplementation level combinations to manipulate the IMF content of various muscle types in ewe and wether prime lambs

Performance and carcass characteristics of Australian purebred and crossbred lambs supplemented with rice bran

Background\ud \ud This study examined the effects of dietary supplementation with rice bran, sire breed and gender on live animal performance and carcass characteristics in Australian crossbred and purebred Merino lambs.\ud \ud Methods\ud \ud Forty-eight lambs balanced by sire breed (Dorset, White Suffolk, Merino) and gender (ewe, wether) were randomly allocated into three dietary supplementation groups (Control- 24 lambs fed wheat/barley-based pellets, Low- 12 animals fed a 50/50 ratio of wheat-based/rice bran pellets, and High- 12 lambs fed rice bran pellets). The Rice bran pellets replaced 19% of the barley component of the feed. Animals were group-fed at the rate of 1000 g of the supplement per head per day with ad libitum access to lucerne hay as the basal diet and water. The duration of the feeding trial was 49 days with an initial 21-day adjustment period.\ud \ud Results\ud \ud Sire breed differences were evident for initial (p < 0.0002) and final (p < 0.0016) liveweights, hot carcass (p < 0.0030) and cold carcass (p < 0.0031) weights, as well as dressing percentage (p < 0.0078), fat thickness (p < 0.0467), yield grade (p < 0.0470) and rib eye area (p < 0.0022) with purebred Merino under-performing compared to the crossbreds. Concentrate feed conversion efficiency, costs per unit of liveweight gain and over the hooks income were comparable between treatments regardless of the observed trend where the high supplementation group tended to show lower feed intake (745.8 g/day) compared to both the control (939.9 g/day) and low supplementation groups (909.6 g/day). No significant differences (p > 0.05) were observed between treatments for live animal performance, carcass characteristics, gender and their second-order interactions.\ud \ud Conclusions\ud \ud Results indicate that Rice bran can be utilised as a cost-effective supplementary feed source in genetically divergent sheep over a 49-day feeding period without detrimental effects on overall live animal performance or carcass characteristics