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Increasing commodity prices of plant proteins pressure farmers to start exploring alternative methods to optimize utilization of these dietary sources; heat treatment (extrusion) is tested in this study. Canola oilcake meal and sweet lupins were extruded to attempt to increase the amount of rumen undegradable protein. Meatmaster lambs were kept under feedlot conditions and fed four different diets: canola oilcake meal, control (CC); canola oilcake meal, extruded (CE); sweet lupins, control (LC); and sweet lupins, extruded (LE) to determine the effect of extrusion on growth performance. Performance parameters such as average daily gain, feed conversion, and feed intake were compared. A feed conversion ratio of 4.62 vs. 4.85 kg feed/kg weight gain was determined for the extruded diet vs. the control diet (not extruded). An average daily gain of 0.310 and 0.320 kg/day were obtained for the control and extruded diets, respectively. Daily feed intake was similar on the extruded (1.440 kg) and control diets (1.437 kg). The performance parameters of lambs on canola oilcake meal (17.4% inclusion) or sweet lupins (26.6% inclusion) were similar. An average fat level of 4 mm (7-9 mm back fat thickness) was achieved, with no effect of processing or protein source. Sweet lupins were identified as an inexpensive, locally-produced alternative plant protein source to canola oilcake meal, with similar performance parameters obtained in feedlot lambs. [ABSTRACT FROM AUTHOR]

One hundred and twelve cross- and purebred pasture-reared lambs were slaughtered at optimal backfat thickness (4 mm). Selected slaughter, carcass, and meat quality characteristics of these animals were assessed. Slaughter age, but not weight, was influenced by genotype, whereas rams were younger and heavier at slaughter than ewes. Throughout, the crossbred genotypes were younger at slaughter than their purebred contemporaries. Merinos had a lower dressing percentage (40.74%) than Dohne Merinos (43.89%), which in turn dressed out substantially lower than all crossbred combinations (~47%). Genotype did not influence the fat or bone percentage in the carcass, but differences existed for the meat percentage. Meat from all groups could be described as very tender (<32.96 N) and acceptable even to consumers not preferring pasture-produced lamb. The reduced slaughter age of crossbred lambs presents the possibility of shortening the production cycle of lamb while simultaneously increasing carcass yields. [ABSTRACT FROM AUTHOR]

Implementation of precision livestock farming requires extensive information to be gathered on the production cycle of slaughter lambs. Constructing accurate growth models for crossbred sheep from the South African flock would provide valuable information towards this goal. Two dam lines, Dohne Merino and Merino, were mated to rams of their own breeds and to three sire lines, namely Dorper, Dormer and Ile de France. Four ram and four ewe lambs from each group were grown out until maturity at one year of age and weighed weekly. The age-weight data thus gathered were fitted to four growth models (Brody, Gompertz, Logistic, and von Bertalanffy) and the accuracy of fit was determined. All four models were deemed to provide a good fit for the data (R² >0.86). Comparison of predicted and observed weights showed that the Gompertz model was the best suited to predicting lifetime growth and therefore it was deemed the best model for this purpose. Crossbred animals generally achieved higher mature weights relative to the pure lines, although Dorper cross ewes were an exception. Rams also gained more benefit from heterosis for mature weights than ewes. [ABSTRACT FROM AUTHOR]

The value of feed protein sources in ruminant nutrition is measured by how effectively the protein is degraded in the rumen and converted into microbial protein. High-producing ruminants acquire high nutritional requirements to sustain their metabolic demands for production and performance. However, protein sources occasionally fall short in supplying the required amount of rumen undegradable protein and amino acids. Chemical treatment (formaldehyde) could be used to increase the efficiency of protein sources, which are highly degradable in the rumen. Canola oilcake meal (CM) and sweet lupin seed (SL) were treated with formaldehyde (40% w/v) at concentrations of 10 g/kg (F10) and 15 g/kg CP (F15). In this study, six Dohne Merino wethers fitted with rumen cannulas were used to determine the effect of formaldehyde treatment on the in situ dry matter and crude protein digestibility. The treatments entailed CM control (CMF0), CM treated with 10 g/kg CP formaldehyde (CMF10), CM treated with 15 g/kg CP formaldehyde (CMF15), SL control (SLF0) SL treated with 10 g/kg CP formaldehyde (SLF10) and SL treated with 15 g/kg CP formaldehyde (SLF15). Treatments were incubated in the rumen at time intervals of 0, 2, 4, 12, 36, 48, 72, and 96 hours. Overall, formaldehyde treatment significantly decreased rumen degradation at all outflow rates of both CM and SL. Therefore, formaldehyde treatment could be used to increase the rumen undegradable protein fraction. Potential improvement in animal performance in terms of live weight gain, average daily gain, and feed conversion efficiency has to be evaluated in production studies. [ABSTRACT FROM AUTHOR]

The effect of the extrusion of canola oilcake meal (COM) and crushed sweet lupins (CSL) with molasses on the dry matter (DM) and crude protein (CP) degradability was determined in situ. Locally sourced (SOILL Moorreesburg, South Africa) COM and CSL, with the addition of 6% molasses, were extruded at a maximum temperature of 116 °C. A total of six Dohne Merino wethers (± 80 kg), fitted with rumen cannula, were used in this trial. Samples in polyester bags (5 g) were incubated in the rumen of the sheep at intervals of 0, 2, 4, 8, 16, 24, and 48 h. The DM and CP disappearances from the rumen were determined and degradability parameters were estimated. Extrusion increased the potentially degradable CP fraction by 43.5%. At each outflow rate, the average CP effective degradability of COM (68.2%) was lower than that of CSL (78.0%). Extrusion substantially lowered the CP effective degradability for both protein sources at every outflow rate tested. The biggest effect was seen at 0.08/h, where effective degradation was lowered by 25.6%. Extrusion with molasses was found to modify ruminal degradation parameters of both canola oilcake meal and crushed sweet lupins, while also decreasing the effective rumen degradation, especially at faster outflow rates. Thereby, the rumen undegradable protein fraction was increased by 85.4%. This study shows that COM and CSL extruded with 6% molasses can substantially increase RUP. [ABSTRACT FROM AUTHOR]

Yearly the ostrich industry loses up to 40% of newly-hatched chicks, partly due to insufficient feed intake. This study was conducted to determine whether the inclusion of various feed flavourants would improve feed intake in ostrich chicks (Trial 1). Ninety-six dayold ostrich chicks were raised in groups of 12 at a Western Cape research farm until 28 days of age. These chicks were provided with free-choice access to a variety of flavoured diets, namely sweet, sour, bitter, salt or an unflavoured control diet. Chicks were found to prefer salty feed, as the salt-flavoured diet had the highest daily feed intake (34% of total) throughout the trial. Subsequently Trial 2 was conducted to determine the preferred level of dietary salt (Experiment 1) as well as the influence dietary salt had on various production parameters (Experiment 2). In Experiment 1, three groups of seven chicks each were offered ad libitum access to diets containing 4 g/kg, 14 g/kg, 24 g/kg, and 34 g/kg of salt respectively. Experiment 1 found that chicks preferred the diet containing 14 g salt/kg (36.4% of total daily feed consumed). For Experiment 2, 56 birds were divided into eight groups of seven. Conversely to the current conventional inclusion of 4 g salt/kg, Experiment 2 showed that chicks reared on a diet containing 14 g salt/kg had a 41.7% higher average daily gain than the group consuming 4 g salt/kg. It can therefore be concluded that ostriches prefer diets with a higher dietary salt level than current conventional diets provide (14 g/kg vs 4 g/kg). [ABSTRACT FROM AUTHOR]

Feed intake models seldom take breed differences into account. This study investigated various approaches to describing and predicting the feed intake of certain breeds (Dohne Merino, Dormer, Dorper, Meatmaster, Merino, South African Mutton Merino (SAMM) and White Dorper). On weaning at 90 days old, four ram and four ewe lambs from each breed were housed under feedlot conditions and reared on a highenergy concentrate-based diet until they reached maturity at about 12 months. Bodyweight and feed intake were recorded weekly. Daily dry matter intake was modelled with bodyweight for each breed using a quadratic function. Feed intake increased to a peak and then tended to decrease as lambs neared maturity. Dormer lambs had the highest peak intake (2202.02 g/day) and Merinos the lowest (1558.8 g/day). However, this model accounted for less than 50% of the variation in the groups. Linear regressions of percentage intake of bodyweight (R² = 0.732) and cumulative feed intake with bodyweight (R² = 0.941) were deemed more reliable in predicting voluntary feed intake. The change in feed conversion ratio was modelled with an exponential relationship. At 75 kg live weight, Dormer rams had the highest feed conversion ratio (20.44) and SAMM rams the lowest (6.48). Generally, lambs with larger frame sizes (Dormer, Dorper and SAMM) presented higher feed intakes at a given bodyweight than smaller-framed breeds. Dorper rams and SAMM lambs proved to have better lifetime feed efficiency than the earlier maturing breeds. [ABSTRACT FROM AUTHOR]

In this study, the wool growth of Dohne Merino, Dormer, Merino and South African Mutton Merino (SAMM) lambs reared on a feedlot diet (10.62 MJ ME/kg feed, 20.7% crude protein) was monitored from about two months old until the lambs were shorn as yearlings. The 100 cm2 patches on the left sides of the lambs were sheared monthly and the clippings were weighed to determine the wool growth rate. At approximately one year old, the lambs were shorn and the fleeces were weighed. A mid rib fleece sample was also retrieved from each lamb for quality analysis. Merino lambs presented the highest wool growth rates (12.943 g/day) and fleece weights (6.140 kg), whereas Dormer lambs exhibited the lowest values for these traits (8.487 g/day and 3.330 kg, respectively (P <0.05)). The lack of differences between Dohne Merino (9.720 g/day and 4.671 kg) and SAMM (10.553 g/day and 4.158 kg) lambs for these wool growth rate and fleece weight traits was attributed to disparities in live weight (86.8 kg and 105.2 kg, respectively (P <0.05), with heavier SAMM lambs offsetting the expected variations in fleece weight. Wool from Dohne Merino and Merino sheep had the finest fibre diameters (<21 µm), followed by SAMM wool (22-23 µm), with Dormers producing coarse wool (>27 µm). These results could be used as guidelines in sheep production to predict the income contribution of wool from these breeds. [ABSTRACT FROM AUTHOR]

Lupins are highly degradable in the rumen, and do not provide enough bypass protein for highproducing ruminant animals. The effects of extrusion on dry matter (DM) and crude protein (CP) rumen degradability of Lupinus albus and Lupinus angustifolius were determined in situ. Samples of both types of lupin were extruded at maximum temperature, which reached 116 °C. Six Dohne Merino wethers fitted with rumen cannulas were used in this trial. Samples were incubated in the rumen at intervals of 0, 2, 4, 12, 36, and 48 hours. This procedure was repeated in two sheep per treatment and in three periods, giving a total of six observations for each variable. Extrusion lowered the soluble fraction of CP and increased the potential degradable fraction without affecting its rate of degradation. It also lowered the effective degradability of CP of both types of lupin by 28% at an outflow rate of 0.08% per hour. No differences were observed between types. Extrusion modified the ruminal degradation parameters and decreased effective rumen degradation, especially at faster outflow rates. Thus, the rumen undegradable protein (RUP) fraction of lupins was increased by extrusion and lupins could be used more efficiently in ruminant diets. This study showed that the benefits of extrusion could be reached at a relatively low temperature of 116 °C to reduce the possibility of heat damage. [ABSTRACT FROM AUTHOR]

Canola meal (CM) is a locally produced protein source that may be less expensive than soybean meal (SBM). This study evaluated the effects of replacing 0%, 25%, 50%, 75%, and 100% SBM with CM in diets for slaughter ostriches. The CM was added at the expense of SBM and other concentrates, with minor changes in other ingredients. Birds (n = 15 per treatment) were reared from 77 to 337 days old on the trial diets, which were supplied ad libitum for starter, grower, and finisher phases. Bodyweights and feed intake were measured during these phases. No differences (P >0.05) were found between treatments for live weight at the end of each phase, dry matter intake (DMI), average daily gain (ADG) and feed conversion ratio (FCR) over all the growth phases. Although no differences were observed in live weight at the end of each phase, the birds reared on the diet with 50% CM were heaviest at slaughter, and birds reared with 100% CM were lightest (P <0.05). Differences (P <0.05) between diets were observed for the weight at slaughter, weights of the liver and thyroid glands and the pH of the cold carcass. However, no differences (P >0.05) were observed between diets for fat pad weight, dressing percentage, and weights of thighs and Muscularis gastrocnemius. The results indicate that CM could replace SBM in the diets of slaughter ostriches without affecting production traits and slaughter yields. [ABSTRACT FROM AUTHOR]

An increasing number of producers opt to finish their lambs in on-farm feedlots. Therefore, detailed production information is required to implement precision finishing of lambs of different genotypes. Precision finishing monitors growth, feed intake and efficiency to optimize management. In this study, feedlot production characteristics of Dohne Merino, Dormer, Dorper, Meatmaster, Merino, Namaqua Afrikaner, and South African Mutton Merino (SAMM) lambs were evaluated. The lambs were reared in a feedlot and fed a diet with 10.41 MJ metabolizable energy (ME)/kg feed and 19.06% crude protein. Feed intake and body weight were recorded weekly from an initial weight of 30 kg until they had the subcutaneous fat cover needed to produce an A2 carcass. Subcutaneous fat was measured on the Longissimus lumborum muscle with an ultrasound scanner. Dorper, Meatmaster and Namaqua Afrikaner had the shortest rearing periods in the feedlot, and were market ready at a lower live weight (P <0.05). As a result, these lambs consumed less feed in the feedlot. Namaqua Afrikaner and Merino lambs were least efficient: 7.08 and 5.63 kg feed/kg gain, respectively. Dohne Merino, Dormer, Dorper, and Meatmaster rams and Dorper ewes were more efficient; approximately 3.58 kg feed/kg gain. Dohne Merino and Dormer rams had the highest growth rates: approximately 465 g/day. The end weights described in this study could be used as an indication for producers of the ideal slaughter weights for breeds of different maturity types. [ABSTRACT FROM AUTHOR]

This research sought to develop a mathematical model to predict the growth and feed intake of Boer goat kids destined for slaughter. Data were collected from castrated kids that were housed in individual pens and fed diets that varied in energy content (11.3, 12.0, and 12.7 MJ metabolizable energy (ME)/kg feed). Growth and feed intake were monitored weekly for 20 weeks, from the time that the kids weighed 22.2 ± 3.5 kg until they were slaughtered at 48.3 ± 0.8 kg. The linear equation (bodyweight = 0.202 age - 5.241 (R² = 0.84)) was found to predict the growth of kids between 126 and 266 days old. Correlations between expressions of intake and bodyweight were evaluated, cumulative feed intake and bodyweight being most highly correlated (r = 0.93). Linear models were developed to predict cumulative feed intake from bodyweight for goats fed each diet. Regression coefficients were compared between diets, with the slope of the equation for goats on the low energy diet (6.74 ± 0.25) being greater than that of the medium (5.80 ± 0.23) and high energy diets (5.82 ± 0.23). This indicates that goats on the medium and high energy diets gained weight more efficiently than those on the low energy diet. The results from this study can be used by goat producers to predict the growth and intake of goats and determine the ideal feedlot finishing period for optimal productivity. [ABSTRACT FROM AUTHOR]

The ostrich industry is poised to recover from the recent lifting of the four-year export ban on fresh meat products to the European Union EU). However, during this period profit margins were severely affected and the need to minimize input costs was as important as it ever was, particularly nutrition. The aim of this study was to evaluate the influence of varying protein concentrations in the diets of slaughter ostriches on the production traits. Five treatment diets were formulated for each feeding phase (pre-starter, starter, grower and finisher), with a control diet, two diets that decreased in protein content and two diets that increased in protein concentration. There were three replications per treatment, resulting in 15 camps, which contained 20 chicks each. Differences were found in live weight of the birds at the end of each feeding phase, except for the finisher phase. Differences were found among the diets for dry matter intake (DMI), average daily gain (ADG), and feed conversion ratio (FCR). The control diet and the two diets that were formulated with higher protein concentrations had higher DMI values, better ADG, and more efficient FCR. Differences were found in cold carcass weights and thigh weights for the birds that were exposed to the treatment diets. The results indicated that the birds on the control diet and on the diets containing higher concentrations of protein, although not differing from each other, consistently outperformed the diets with lower concentrations of protein. From a financial standpoint it can be concluded that it does not make sense to increase the protein concentration in the diets beyond that currently used in the ostrich industry, while a decrease in protein concentration resulted in decreased production performance. [ABSTRACT FROM AUTHOR]

Nutrition contributes approximately 75% of the total input costs to an intensive ostrich production unit. An increase in the price of traditional protein sources thus necessitates finding cheaper alternatives. Sweet lupins were identified as a possible alternative; therefore, the effect of feeding various sweet lupin inclusion levels was evaluated throughout the different feeding phases. One hundred and forty ostrich chicks were randomly divided into five dietary treatments with three replications each. The chicks all received a standard commercial pre-starter ostrich diet. Five iso-nutritional diets were formulated for each feeding phase according to specifications set out for each of the different feeding phases using Mixit2+ software. For each feeding phase the diets contained either soybean oilcake meal (control diet, 0LD) or sweet lupins (alternative protein source). The 100 lupin diet (LD) was formulated to include the maximum amount of sweet lupins according to the specifications for the specific species and the feeding phase, and therefore differs between the three feeding phases. Soybean oilcake meal was thus gradually replaced by sweet lupins in the following ratios: 100:0 (0LD), 75:25 (25LD), 50:50 (50LD), 25:75 (75LD), and 0:100 (100LD). Feed and water were supplied ad libitum. Feed intakes and live weights were measured every fortnight until slaughter at ca. 11 months of age. No differences were found between the treatment diets for the live weight, dry matter intake (DMI), average daily gain (ADG) or feed conversion ratio (FCR) at the end of each feeding phase. However, the birds on the 75LD tended to have the highest end weight and ADG, and those on the 100LD the lowest at the end of the starter phase. No differences were found for slaughter weight, dressing percentage and big drum muscle weight of the birds. Birds on the 50LD and 75LD tended to have the heaviest cold carcasses; this differed from the 100LD birds which had the lightest. Birds fed the 50LD had heavier thigh weights than those on the other diets. The results of this study indicate that soybean oilcake meal can be replaced in the diets of slaughter ostriches with sweet lupins up to 15% (75LD) in starter diets and 30% (100LD) in grower and finisher diets without any significant effect on any of the production and slaughter traits. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effect of time spent in a feedlot on the size of the various fat depots and the distribution of the main tissues (muscle, bone, and fat) of three common South African sheep breeds. Lambs were supplied with a balanced diet (16% protein, 10 MJ ME/kg feed) ad libitum and had free access to water. Lambs from each breed were divided into six groups, which were slaughtered at 21-day intervals until a production period of 105 days had been reached. During carcass dressing, visceral and renal fat was removed and expressed as a percentage of carcass weight. The subcutaneous fat (SCF) depth was measured on the longissimus lumborum at the 13th rib position using an electronic calliper. The proportion of muscle, bone and fat was determined by dissecting a three-rib cut made on the prime rib between the 9th and 11th ribs. The percentage of visceral and renal fat increased throughout the production period for all breeds. The percentage of renal fat was up to 2.9% higher than the percentage visceral fat in both SAMM production groups. Dorper lambs tended to have high SCF levels (5.6 mm fat after 42 days) due to the early maturing nature of the breed. They reached a maximum fat depth of 20.4 mm fat after 105 days. The SAMM lambs tended to deposit SCF at a slower rate and the late maturing Merino breed was found to be much leaner, and did not reach the high fat levels of the SAMM or Dorper lambs. The percentage of muscle and bone in all carcasses decreased with an increase in the number of days in the feedlot, while the percentage of carcass fat increased during this period. The increase in late maturing adipose tissue in all breeds as they become older is amplified by the restricted movement in the feedlot and high energy diet that the lambs receive. [ABSTRACT FROM AUTHOR]

This study investigated the effect of feedlot production on lamb growth characteristics of three common South African breeds: Merino, South African Mutton Merino (SAMM) and Dorper. Lambs were supplied with a balanced diet (16% crude protein, 9.41 MJ ME/kg feed) ad libitum and had free access to water. Lambs from each breed were divided into six groups. One group of each breed was slaughtered every three weeks until 105 days under feedlot production were reached. The weights of the lambs were recorded weekly, along with feed intake, to obtain the individual daily intake, average daily gain (ADG) and feed conversion ratio (FCR) for each lamb. The ADG for the SAMM 2007 and Dorper lambs increased throughout their production period, while that of the SAMM 2008 and Merino lambs tended to decrease with time, although the SAMM 2008 group achieved the highest ADG of 350.2 g/lamb/day of all the breeds. The Dorper and SAMM 2007 lambs had higher FCR (7.52 and 7.58, respectively). The average FCR achieved by the SAMM 2008 and Merino lambs was 5.54 and 5.14, respectively. However, the FCR of Merino and SAMM 2008 lambs increased throughout the production period. The Dorper lambs produced fatter carcasses and therefore exhibited the highest average dressing percentage of 49.7% compared with the SAMM 2007 (48.4%) and 2008 lambs (45.6%), followed by the Merino lambs (43.9%). The results confirm that the Merino is a late maturing breed that is recognised for its wool rather than meat production, and therefore exhibits weaker growth characteristics. The SAMM is a dual-purpose breed that has also been selected for growth and meat production, and therefore exhibits desirable production characteristics, while the Dorper is an early maturing breed that deposits localized fat at an earlier age as it grows, thereby producing fatter carcasses than SAMM and Merino lambs. Therefore, Dorper lambs should be slaughtered at lower live weights so that carcasses are not graded as over-fat. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the conception rate and fecundity of Dohne Merino ewes in an intensive sheep production system, where continuous mating was applied. The study was conducted at the Kromme Rhee research farm. Ninety-two 3-year-old Dohne Merino ewes were used in the trial and allocated to irrigated-lucerne equal-sized paddocks of 0.85 ha. Rotational grazing was applied at a stocking rate of 15 ewes per hectare, with rams left with the ewes continuously. A self-formulated creep feed and lick was provided to the lambs and ewes, respectively, on an ad libitum basis. The experimental animals were weighed every second week and lambs were weaned at approximately 120 days of age. The statistical procedures indicated that 65.4% of the ewes conceived within 81 days after lambing. Analyses of variance (ANOVA) were performed on the observed variables. The Shapiro-Wilk test was performed to test for normality and Student's-t least significant differences (LSD) were calculated at the 5% level of confidence, to compare the treatment means. Regression analyses were performed to establish the contribution of each variable to the predicted "days after lambing". The stepwise selection method was executed in order to select the variables that significantly contributed to the predicted "days after lambing". There was no significant difference in "days after lambing" and conception weight between ewes that produced single, twin or triplet lambs. Results also indicated that a more rapid breeding system is achievable on irrigated pastures. However, the sustainability of such a system needs to be tested further to determine the effect of the accelerated system on the productive lifespan of the ewes. [ABSTRACT FROM AUTHOR]

Earlier studies on breeding birds indicated no effect of dietary energy-content on feed intake. This observation is contradictory to results for other animals and/or poultry where feed intake decreases with an increase in dietary energy level. Literature revealed that a lack of certain nutrients may cause animals to consume more feed than necessary to satisfy their nutrient requirements for these limiting nutrients. In this study eight diet groups were evaluated. A standard commercial diet plus one of the following supplements: (i) Standard diet without a vitamin and mineral premix pack (control diet), (ii) with a normal premix pack, (iii) with normal vitamin and 2 x trace elements (M x 2), (iv) with normal trace elements and 2 x vitamins, (v) with a normal premix pack and limestone added as calcium source; (vi) with a normal premix pack and monocalcium phosphate added as phosphorus source, (vii) with a normal premix pack and soybean oilcake added as crude protein source, (viii) with a normal premix pack and linseed added as a fatty acid source. Significant differences were recorded in the quantity of feed ingested by birds between the diet with surplus minerals (M x 2) (Group 3) (2.3 ± 0.3 kg/bird/day), the diet with no vitamins and minerals added (Group 1) (2.7 ± 0.3 kg/bird/day) and the diet with added fatty acids in the form of linseed (Group 5) (2.9 ± 0.5 kg/bird/day). This indicates the possibility that ostriches may adjust feed intake to satisfy their mineral requirements. No statistically significant relationship was found between the thickness and strength of the shell. Significant differences in shell strength (mean value of 154.7, 109.9, 140.4, 142.7, 153.0, 143.4, 138.4 and 151.1 N/cm², respectively) were found between all treatments, but no specific pattern could be identified. Results further revealed no effect of dietary treatment on egg production, dead-in-shell eggs (DIS), infertile eggs or chick production. Further experiments that include certain dietary treatments during the five months rest period are currently being done to quantify the effect of the addition of minerals and vitamins during this period on the production of breeding ostriches. [ABSTRACT FROM AUTHOR]

ß-adrenergic agonists are commonly used in livestock production to enhance meat production and decrease the fat content of the body. ß-adrenergic agonists normally improve growth performance. Recent increases in meat prices and the change in consumer preference towards leaner meat have resulted in more lamb producers opting to finish leaner mutton/lamb on farms in a feedlot system. The aim of this trial was to determine the effect of dietary energy, as well as the inclusion of a ß-antagonist, on the meat quality of feedlot lambs. South African Mutton Merino lambs (108) of different sexes (rams and ewes) were weaned at 120 days of age and were randomly divided into six groups (18 lambs per group). The treatment consisted of three different dietary energy levels (high 12.7 MJ ME/kg feed, medium 12.0 MJ ME/kg feed and low 11.3 MJ ME/kg feed) with either the inclusion of a ß-adrenergic agonist (zilpaterol hydrochloride) at 8.4 g/ton or not. Data were analysed according to a 3 (dietary energy) x 2 (inclusion of a stimulant) x 2 (sex) factorial analysis. No interaction occurred between treatments and the data were presented as the effect of dietary energy level, the inclusion of a stimulant and sex on proximate components, fat thickness and the tenderness of the meat. The factors ß-adrenergic agonists and dietary energy level had no effect on the proximate components, fat thickness or the tenderness of the meat. The ewe lambs' 9-11th rib-cut had a significantly higher fat content than the ram lambs (27.9% vs. 23.1%, respectively). Meat from ram lambs was less tender (63.60N) compared to that from ewe lambs (57.82N). Neither the inclusion of the ß-adrenergic agonist (59.8N vs. 61.9N) nor the dietary energy level (59.3N vs. 63.5N vs. 59.3N) had an effect on the tenderness of meat from lambs in this study. [ABSTRACT FROM AUTHOR]

Recent increases in mutton lamb prices have resulted in many lamb producers opting to finish more and more lambs on the farms in a feedlot system rather than marketing directly from the field. The aim of this trial was to determine the effect of dietary energy, as well as the inclusion of a ß-adrenergic agonist, on the production of feedlot lambs. South African Mutton Merino lambs (108) of different sexes were weaned (± 36.4 kg) at ca. 120 days of age and were randomly divided into six experimental groups (18 lambs per group), which were adapted to each treatment. Lambs were housed in individual pens. The treatments consisted of three diets (diet 1: 11.3 MJ ME/kg food, diet: 2 12.0 MJ ME/kg food and diet 3: 12.7 MJ ME/kg) with either the inclusion or absence of a ß-adrenergic agonist at 8.5 g/ton. The experimental design was a 3 x 2 x 2 factorial design with dietary energy level, the provision of a ß-adrenergic agonist and sex as main factors. No interaction occurred between treatments and data are presented as the effect of dietary energy level and the inclusion of a stimulant on the intake, growth and feed conversion ratio (FCR). Neither the dietary energy content nor the ß-adrenergic agonist had an effect on FCR. Neither one of the main factors had a significant effect on feed intake. The sex of the lambs had a significant effect on the average daily gain of the lambs with the ewes growing faster than the rams. [ABSTRACT FROM AUTHOR]

This study was performed to obtain information on yolk utilization in fasted and fed ostrich chicks posthatching. The fasted trial lasted for 7 d, whereas the fed trial continued for 16 d. Fasted ostrich chicks showed a decrease of 31.3 g of BW, with yolk weight decreasing by 28.9 g daily after hatching. Yolk weight comprised 28% of 1-d-old ostrich chick BW and decreased to 12% at 7 d of age. Only 44.4% of the fasted ostrich chick yolk was assimilated over the trial period. Crude protein content of the yolk decreased by 13.2 g daily. Fat content increased by 1.77% daily, whereas total yolk fat weight decreased with 8.91 g daily. Slaughter weight of fed ostrich chicks increased, with yolk weight decreasing by 16.3 g daily. Yolk content for fed ostrich chicks was 26% of BW at 2 d of age. Ostrich chicks absorb 30% of yolk over the first 4 d, 67% after 8 d, and only deplete the yolk after 14 d posthatch. Fasted ostrich chicks absorbed the yolk content at a rate of 28.9 g/d, compared with 22.3 g/d over the first 8 d and 16.3 g/d over the 16 d for fed ostrich chicks. The CP content of the yolk decreased by 6.84 g daily in fed ostrich chicks, whereas fat content of the yolk increased by 1.39% daily, although total yolk fat weight decreased by 6.61 g daily. Yolk weight and total CP decreased faster over the first 7 d in the fasted ostrich chicks compared with the fed ostrich chicks, which indicated that the decrease in yolk weight could be attributed to absorption of protein from the yolk. Fat content decreased faster over the first 8 d from the yolk of the fed ostrich chicks compared with that from the yolk of the fasted ostrich chicks, which could indicate that external feed has a positive influence on the absorption of fat from the yolk content. [ABSTRACT FROM AUTHOR]

A study was conducted to describe the changes occurring in body composition of ostriches over a 285-day growth period. Fifty two birds were given a choice of four diets with different protein (180 and 120 g/kg feed) and energy (8.5 and 13.5 MJ ME/kg feed) levels, on the assumption that the birds would select from the four feeds according to their protein and energy requirements, and thereby grow close to their potential without being constrained by the quality of feed supplied to them. Birds were weighed at approximately 10-day intervals and randomly selected birds were slaughtered at 1, 54, 120, 162 and 285 days of age respectively. Proximate analyses were done on the complete empty carcasses and the components were expressed as a percentage of live weight at the different slaughter ages. The Gompertz growth curve was fitted to the live weights of the birds and to the weights of the individual chemical components. The change in body weight with age as the only independent variable can be considered as a good (R² = 0.93) description of growth in ostriches. The growth parameters a, b and c were estimated as 119.4, 0.009 and 156.3 respectively. Body protein and moisture concentrations decreased as the birds aged, while the body ash concentration remained relatively constant and body fat concentration increased. Fitted Gompertz parameters for the different chemical components were, for fat; a = 33.6, b = 0.013 and c = 143.4 (R² = 0.914), protein; a = 44.5, b = 0.015 and c = 113.9 (R² = 0.961), ash; a = 10.3, b = 0.016 and c = 118.2 (R² = 0.965), and moisture; a = 55.0, b = 0.014 and c = 116.9 (R² = 0.965). Similar to other animals, fat was a late maturing tissue and protein a relatively early maturing tissue. These results are important in describing the growing ostrich and this information can be used to model the nutrient requirements of these birds. [ABSTRACT FROM AUTHOR]

The development of low erucic acid, low glucosinolate cultivars of canola seed has led to the availability of a feed ingredient with considerable potential to replace soyabean meal in diets for all classes of farm animals. The sinapine and glucosinolate content of various canola cultivars cultivated in two areas of the Western Cape, South Africa were compared. There were no significant differences in sinapine content between the canola produced in the Western and Southern Cape (mean value of 9.95 mg sinapine/g grain). There were cultivar differences, with Varola 54 and Rainbow cultivars having significantly higher sinapine concentrations than Varola 50. There were no significant differences between the aliphatic, indolyl or aromatic glucosinolate content of the canola originating from either the Swartland or the Rûens areas in South Africa (mean value of 17.84 µmol total glucosinolates/g grain). There were significant differences in the total glucosinolate content of the various canola cultivars. Varola 44 and Hylite 200TT had the lowest total glucosinolate concentration and Varola 50 had the highest glucosinolate concentration. The results obtained seem to indicate a maximum dietary inclusion level of up to 14% for South African produced canola with an average of 17.83 µmol glucosinolates per gram to ensure optimal animal production. [ABSTRACT FROM AUTHOR]

Samples of sweet yellow lupins (Lupinus luteus; n = 4), broad leaf lupins (Lupinus albus; n = 12), narrow leaf lupins (Lupinus angustifolius; n = 8), faba beans (Vicia faba; n = 2), field peas (Pisum sativum; n = 4) and narbon beans (Vicia narbonensis; n = 2) were collected over a two-year period. The physical characteristics (thousand seed and hectolitre mass), chemical composition (dry matter, ash, crude protein (CP), ether extract, acid detergent fibre, neutral detergent fibre and mineral content), energy values (nitrogen corrected true metabolisable energy content (TMEn for roosters)) as well as the lysine and methionine availability (with roosters) of the samples were determined. Lupinus albus had the highest TMEn (12.49 MJ/kg), followed by field peas (11.35 MJ/kg) and narbon beans (11.25 MJ/kg), faba beans (10.90 MJ/kg), L. angustifolius (10.46 MJ/kg) and L. luteus (10.20 MJ/kg). Lupinus luteus had the highest CP concentration (393.6 g/kg) followed by L. albus (381.9 g/kg), L. angustifolius (338.9 g/kg), faba beans (260.0 g/kg), field peas (247.4 g/kg) and narbon beans (237.6 g/kg) (values on a dry matter basis). Lupinus luteus had the highest lysine concentration (22.2 g/kg), followed by L. albus (19.6 g/kg), field peas (19.3 g/kg), L. angustifolius (18.6 g/kg), narbon beans (17.5 g/kg) and faba beans (17.0 g/kg). [ABSTRACT FROM AUTHOR]

Nutrition of breeding female birds can influence egg quality and is therefore extremely important for the development of the embryo and the successful hatching of a high quality chick. We investigated the effect of combining different levels of dietary energy and protein, with accompanied amino acid levels, in the diets of female ostriches on the composition of their eggs. Ninety pairs of breeding ostriches were divided randomly into nine groups of 10 pairs per group in a factorial design with three energy and three protein levels. The groups were fed diets with levels of 7.5, 8.5 and 9.5 MJ metabolisable energy/kg, each combined with each one of three protein levels 105, 120 and 135 g/kg respectively. Fresh eggs were collected from each group at the end of the breeding season and the albumen and yolk separated and analysed for protein and lipid content and for amino acid and mineral composition. No significant interaction between energy and protein levels occurred. Despite some differences in egg composition and amino acid concentrations, different dietary energy and protein levels for the most part had little or no effect on the composition of ostrich eggs. [ABSTRACT FROM AUTHOR]