Salinity tolerance of twelve hybrid Bermudagrass (Cynodon Dactylon (L.) Pers. x C. Transvaalensis Burtt Davy) genotypes

Salinity is an increasingly important issue in both rural and urban areas throughout much of Australia. The use of recycled/reclaimed water and other sources of poorer quality water to irrigate turf is also increasing. Hybrid Bermudagrass (Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt Davey), together with the parent species C. dactylon, are amongst the most widely used warm-season turf grass groups. Twelve hybrid Bermudagrass genotypes and one accession each of Bermudagrass (C. dactylon), African Bermudagrass (C. transvaalensis) and seashore paspalum (Paspalum vaginatum Sw.) were grown in a glasshouse experiment with six different salinity treatments applied hydroponically through the irrigation water (ECW = <0.1, 6, 12, 18, 24 or 30 dSm-1) in a flood-and-drain system. Each pot was clipped progressively at 2-weekly intervals over the 12-week experimental period to determine dry matter production; leaf firing was rated visually on 3 occasions during the last 6 weeks of salinity treatment. At the end of the experiment, dry weights of roots and crowns below clipping height were also determined. Clipping yields declined sharply after about the first 6 weeks of salinity treatment, but then remained stable at substantially lower levels of dry matter production from weeks 8 to 12. Growth data over this final 4-week experimental period is therefore a more accurate guide to the relative salinity tolerance of the 15 entries than data from the preceding 8 weeks. Based on these data, the 12 hybrid Bermudagrass genotypes showed moderate salinity tolerance, with FloraDwarfM, 'Champion Dwarf', NovotekM and 'TifEagle' ranking as the most salt tolerant and 'Patriot', 'Santa Ana', 'Tifgreen' and TifSport M the least tolerant within the hybrid group. Nevertheless, Santa Ana, for example, maintained relatively strong root growth as salinity increased, and so may show better salt tolerance in practice than predicted from the growth data alone. The 12 hybrid Bermudagrasses and the single African Bermudagrass genotype were all ranked above FloraTeXM Bermudagrass in terms of salt tolerance. However, seashore paspalum, which is widely acknowledged as a halophytic species showing high salt tolerance, ranked well above all 14 Cynodon genotypes in terms of salinity tolerance.

Morphological and developmental comparisons of seven greens quality hybrid bermudagrass (Cynodon dactylon (L.)Pers.x C transvaalensis Burtt-Davy

Fine-textured hybrid bermudagrass [Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy] cultivars have been widely used for golf putting greens and lawn bowls greens in warm-climate areas for more than 40 years. During the past decade, the choice of cultivar for professional turfgrass managers has been expanded by a range of secondgeneration hybrid bermudagrasses, which differ from the first-generation cultivars ‘Tifgreen’ and ‘Tifdwarf ’ in their management requirements. In this paper, we present comparative morphological and developmental data for seven cultivars (Champion Dwarf, FloraDwarf, MS-Supreme, Novotek, Tifdwarf, TifEagle, Tifgreen) grown in spaced plant and sward experiments at Cleveland, Australia (27º32’S lat, 153º15’E long, 25 masl). The four ‘ultradwarf ’ cultivars (Champion Dwarf, MS-Supreme, FloraDwarf, TifEagle) showed slower vertical extension and produced fewer inflorescences than Tifdwarf, Tifgreen, and Novotek. However, in terms of the length of stolon internodes and their overall rate of lateral spread, Champion Dwarf, FloraDwarf, and TifEagle were comparable to Tifdwarf; MS-Supreme (with longer internodes) spread faster laterally, though slower than Tifgreen (which had the longest stolon internodes). In unmown swards, the four ultradwarfs produced shorter leaves than Tifgreen, Tifdwarf, and Novotek, but only Champion Dwarf produced significantly narrower leaves than Tifgreen, Tifdwarf, and Novotek, with TifEagle leaves also significantly narrower than those of Tifgreen and Novotek. Minimum threshold temperatures for growth were approximately 9° to 10°C (air temperature) and 15° to 16°C at 10 cm soil depth.

Cynodon dactylon Green Couch Grass, Bermuda Grass 'JT1'

Spontaneous mutation or chance seedling: discovered in the mid-1990s as a superior plant growing in a commercial field of “Common” Cynodon dactylon on Jimboomba Turf Company’s farm at Jimboomba in south-east Queensland. Selection criteria: vigorous lateral spread, high shoot density and turf quality, low inflorescence numbers, and darker green colour. In 1999 after observing the superior turf performance of this mutant plant as a small patch within a much larger paddock of “Common”, vegetative material was taken and propagated in clean ground elsewhere on the farm for multiplication and further trials in a variety of turf situations in south-east Queensland. Propagation: vegetative. Breeder: Lynn Davidson, Jimboomba, QLD. PBR Certificate Number 2640, Application Number 2002/282, granted 24 February 2005.

Taxonomy, distribution and ecology of Zoysia macrantha desv., an Australian native species with turf breeding potential

Only three of the 11 species in the genus Zoysia Willd. have thus far contributed to commercially available turfgrass varieties. One of the neglected taxa is Z. macrantha Desv., an Australian native species further divided into two subspecies. The coarser Z. macrantha subsp. macrantha occurs on sand dunes, headlands and tidal areas along eastern and southeastern coasts from about 23 to 38°S latitude. The shorter, denser-growing Z. macrantha subsp. walshii M.E. Nightingale is found on the southern mainland (South Australia and Victoria from longitude 137° to 148°E and at latitudes higher than 36°S), adjacent offshore islands, and northern, eastern and central Tasmania to 43°S growing on the edges of coastal, sub-coastal and even inland salt lakes, in riverine environments, and from moist grassy depressions (both coastal and inland) to rocky headlands. The latter subspecies has the more discontinuous and specialised distribution, largely determined by the need for an appropriate level of peat, clay or silt in the soil to maintain adequate moisture during the dry summers in southern Australia while at the same time avoiding anything more than temporary waterlogging. It grows on low fertility soils ranging from strongly acid to neutral or mildly alkaline, and is often very closely grazed by marsupials. Both subspecies are salt and drought tolerant, but not notably shade tolerant. Their potential to add greater drought tolerance in particular to the Asian Zoysia material in current use through future breeding programs is discussed.

Management Guidelines for New Warm-Season Grasses in Australia

After more than 30 years in which ‘Tifgreen’ and ‘Tifdwarf’ were the only greens-quality varieties available, the choice for golf courses and bowls clubs in northern Australia has been expanded to include six new Cynodon hybrids [Cynodon dactylon (L.) Pers x Cynodon transvaalensis Burtt-Davy]. Five of these – ‘Champion Dwarf’ (Texas), ‘MS-Supreme’ (Mississippi), FloraDwarf™ (Florida), ‘TifEagle’ (Georgia), MiniVerde™ (Arizona) - are from US breeding programs, while the sixth, ‘TL2’ (marketed as Novotek™) was selected in north Queensland. The finer, denser and lower growing habit of the “ultradwarf” cultivars allows very low mowing heights (e.g. 2.5 mm) to be imposed, resulting in denser and smoother putting and bowls surfaces. In addition to the Cynodon hybrids, four new greens quality seashore paspalum (Paspalum vaginatum O. Swartz) cultivars including ‘Sea Isle 2000’, Sea Isle Supreme™, Velvetene™ and Sea Dwarf™ (where tolerance of salty water is required) expands the range of choices for greens in difficult environments. The project was developed to determine (a) the appropriate choice of cultivar for different environments and budgets, and (b) best management practices for the new cultivars which differ from the Cynodon hybrid industry standards ‘Tifgreen’ and ‘Tifdwarf’. Management practices, particularly fertilising, mowing heights and frequency, and thatch control were investigated to determine optimum management inputs and provide high quality playing surfaces with the new grasses. To enable effective trialling of these new and old cultivars it was essential to have a number of regional sites participating in the study. Drought and financial hardship of many clubs presented an initial setback with numerous clubs wanting to be involved in the study but were unable to commit due to their financial position at the time. The study was fortunate to have seven regional sites from Queensland, New South Wales, Victoria and South Australia volunteer to be involved in the study which would add to the results being collected at the centralised test facility being constructed at DEEDI’s Redlands Research Station. The major research findings acquired from the eight trial sites included: • All of the new second generation “ultradwarf” couchgrasses tend to produce a large amount of thatch with MiniVerde™ being the greatest thatch producer, particularly compared to ‘Tifdwarf’ and ‘Tifgreen’. The maintenance of the new Cynodon hybrids will require a program of regular dethatching/grooming as well as regular light dustings of sand. Thatch prevention should begin 3 to 4 weeks after planting a new “ultradwarf” couchgrass green, with an emphasis on prevention rather than control. • The “ultradwarfs” produced faster green speeds than the current industry standards ‘Tifgreen’ and ‘Tifdwarf’. However, all Cynodon hybrids were considerably faster than the seashore paspalums (e.g. comparable to the speed diference of Bentgrass and couchgrass) under trial conditions. Green speed was fastest being cut at 3.5 mm and rolled (compared to 3.5 mm cut, no roll and 2.7 mm cut, no roll). • All trial sites reported the occurrence of disease in the Cynodon hybrids with the main incidence of disease occurring during the dormancy period (autumn and winter). The main disease issue reported was “patch diseases” which includes both Gaumannomyces and Rhizoctonia species. There was differences in the severity of the disease between cultivars, however, the severity of the disease was not consistent between cultivars and is largely attributed to an environment (location) effect. In terms of managing the occurrence of disease, the incidence of disease is less severe where there is a higher fertility rate (about 3 kgN/100m2/year) or a preventitatve fungicide program is adopted. • Cynodon hybrid and seashore paspalum cultivars maintained an acceptable to ideal surface being cut between 2.7 mm and 5.0 mm. “Ultradwarf” cultivars can tolerate mowing heights as low as 2.5 mm for short periods but places the plant under high levels of stress. Greens being maintained at a continually lower cutting height (e.g. 2.7 mm) of both species is achievable, but would need to be cut daily for best results. Seashore paspalums performed best when cut at a height of between 2.7 mm and 3.0 mm. If a lower cutting height is adopted, regular and repeated mowings are required to reduce scalping and produce a smooth surface. • At this point in time the optimum rate of nitrogen (N) for the Cynodon hybrids is 3 kg/100m2/year and while the seashore paspalums is 2 to 3 kg/100m2/year. • Dormancy occurred for all Cynodon and seashore paspalum culitvars from north in Brisbane (QLD) to south in Mornington Peninsula (VIC) and west to Novar Gardens (SA). Cynodon and Paspalum growth in both Victoria and South Australia was less favourable as a result of the cooler climates. • After combining the data collected from all eight sites, the results indicated that there can be variation (e.g. turfgrass quality, colour, disease resistance, performace) depending on the site and climatic conditions. Such evidence highlights the need to undertake genotype by environment (G x E) studies on new and old cultivars prior to conversion or establishment. • For a club looking to select either a Cynodon hybrid or seashore paspalum cultivar for use at their club they need to: - Review the research data. - Look at trial plots. - Inspect greens in play that have the new grasses. - Select 2 to 3 cultivars that are considered to be the better types. - Establish them in large (large enough to putt on) plots/nursery/practice putter. Ideally the area should be subjected to wear. - Maintain them exactly as they would be on the golf course/lawn bowls green. This is a critical aspect. Regular mowing, fertilising etc. is essential. - Assess them over at least 2 to 3 years. - Make a selection and establish it in a playing green so that it is subjected to typical wear.

Warm-season greens grass trial - Environmental and management guidelines suited for new and old cultivars

The Horticulture Australia funded project, Management Guidelines for Warm-Season Grasses in Australia (TU05001), has allowed a detailed greens grass study to take place and enabled researchers and superintendents to work together to collect meaningful data on a range of Cynodon dactylon (L.) Pers. x Cynodon transvaalensis Burtt-Davy (Cynodon hybrid) and Paspalum vaginatum O. Swartz (seashore paspalum) cultivars suitable for golf or lawn bowls use. The end result provides superintendents and greenkeepers with additional knowledge to accompany their skills in managing or upgrading their greens to produce a denser, smoother and faster putting or bowls surface. However, neither turfgrass selection nor finely tuned management program will overcome unrealistic expectations (especially in relation to usage), poor growing environments, or limitations due to improper construction techniques.

Male traits and herd reproductive capability in tropical beef cattle. 1. Experimental design and animal measures

Research into the genetics of whole herd profitability has been a focus of the Beef Cooperative Research Centre for Beef Genetic Technologies over the past decade and it has been identified that measures of male reproduction may offer a potential indirect means of selecting for improved female reproduction. This paper describes the experimental design and provides a descriptive analysis of an array of male traits in Brahman and Tropical Composite genotypes managed under the medium to high stress, semi-extensive to extensive production systems of northern Australia. A total of 1639 Brahman and 2424 Tropical Composite bulls with known pedigrees, bred and raised in northern Australia, were evaluated for a comprehensive range of productive and reproductive traits. These included blood hormonal traits (luteinising hormone, inhibin and insulin-like growth factor-I); growth and carcass traits (liveweight, body condition score, ultrasound scanned 12-13th rib fat, rump P8 fat, eye muscle area and hip height); adaptation traits (flight time and rectal temperature); and a bull breeding soundness evaluation (leg and hoof conformation, sheath score, length of everted prepuce, penile anatomy, scrotal circumference, semen mass activity, sperm motility and sperm morphology). Large phenotypic variation was evident for most traits, with complete overlap between genotypes, indicating that there is likely to be a significant opportunity to improve bull fertility traits through management and bull selection.

Male traits and herd reproductive capability in tropical beef cattle. 2. Genetic parameters of bull traits

A total of 4063 young bulls of two tropical genotypes (1639 Brahman and 2424 Tropical Composite) raised in northern Australia were evaluated for a comprehensive range of production and reproduction traits up to 24 months of age. Prior to weaning, peripheral blood concentrations of luteinising hormone (LH) and inhibin were measured at 4 months of age. At weaning (6 months) blood insulin-like growth factor-1 (IGF-I) and flight time were recorded. Body composition traits of fat depth and eye-muscle area were determined by ultrasonography at 15 months of age when additional measurements of liveweight, hip height and body condition score were recorded. Bull breeding soundness was evaluated at similar to 12, 18 and 24 months of age when measurements of scrotal circumference, sheath score, semen mass activity, progressive motility of individual sperm and percent morphologically normal sperm were recorded. Magnitude of heritability and genetic correlations changed across time for some traits. Heritability of LH, inhibin, IGF-I and of 18-month scrotal circumference, mass activity, progressive motility and percent normal sperm was 0.31, 0.74, 0.44, 0.75, 0.24, 0.15 and 0.25, respectively, for Brahmans and 0.48, 0.72, 0.36, 0.43, 0.13, 0.15 and 0.20, respectively, for Tropical Composites. Inhibin and IGF-I had moderate genetic association with percent normal sperm at 24 months in Brahmans but low to negligible associations in Tropical Composites. Body condition score in Brahmans and sperm motility (mass and individual) traits in both genotypes had moderate to strong genetic correlation with percent normal sperm and may prove useful candidates for indirect selection. There is scope to increase scrotal circumference by selection and this will be associated with favourable correlated responses of improved semen quality in both genotypes. The lack of genetic antagonism among bull traits indicates that selection for improved semen quality will not adversely affect other production traits.

Controlling voluntary intake of molasses-based supplements in grazing cattle

Molasses-based liquid supplements fed ad libitum are widely used to provide additional metabolisable energy, non-protein N (NPN) and other nutrients to grazing cattle, but it is often difficult to achieve target intakes of supplementary nutrients. Experiments examined the effects of increasing concentrations of phosphoric acid, urea and ammonium sulfate on the voluntary intake (VI) of molasses-based supplements offered ad libitum to heifers grazing tropical pastures. In Experiment 1, the VI of a supplement containing 78 g urea/kg and 26 g phosphoric acid/kg as-fed (M80U+PA) was 3.61 g DM/kg liveweight (LW) per day, and provided 181 mg NPN and 32.4 mg phosphorus (P)/kg LW per day. Increasing the urea content of the supplement to 137 g/kg (M140U+PA) or 195 g/kg (M200U+PA) reduced VI of supplement DM, NPN and P by up to 76%, 44% and 80%, respectively. VI of supplement containing ammonium sulfate (M140+AS+PA) was lower (P < 0.05) than that of M140U+PA supplement, and tended (P > 0.05) to be lower than that of M200U+PA supplement. In experiment 2, the VI by heifers of a supplement containing 200 g urea/kg (M200U) was 1.53 g supplement DM/kg LW per day, which provided 186 mg NPN/kg LW per day. Inclusion of 49 g phosphoric acid/kg as-fed in this supplement (M190U+50PA) reduced (P < 0.05) VI of supplement DM and NPN by 33% and 36%, respectively, while inclusion of 97 g phosphoric acid/kg (M180U+100PA) reduced (P < 0.05) VI of supplement DM and NPN by 43% and 48%, respectively. The M190U+50PA and M180U+100PA supplements provided 16 and 26 mg P/kg LW per day, respectively. Heifers not fed supplements gained 0.07 kg/day, and the M200U supplement increased (P < 0.05) LW gain to 0.18 kg/day. LW gain was further increased (P < 0.05) by the M190U+50PA to 0.28 kg/day, indicating a growth response to supplementary P. No adverse effects of the supplements on animal health were observed in any of the experiments. In conclusion, addition of urea and/or phosphoric acid to molasses supplements effectively reduced VI of supplementary DM, NPN and P, and in the circumstances of Experiment 2, both molasses-urea and P supplements increased heifer LW.

Liveweight prediction from hip height, condition score, fetal age and breed in tropical female cattle

Hip height, body condition, subcutaneous fat, eye muscle area, percentage Bos taurus, fetal age and diet digestibility data were collected at 17 372 assessments on 2181 Brahman and tropical composite (average 28% Brahman) female cattle aged between 0.5 and 7.5 years of age at five sites across Queensland. The study validated the subtraction of previously published estimates of gravid uterine weight to correct liveweight to the non-pregnant status. Hip height and liveweight were linearly related (Brahman: P<0.001, R-2 = 58%; tropical composite P<0.001, R-2 = 67%). Liveweight varied by 12-14% per body condition score (5-point scale) as cows differed from moderate condition (P<0.01). Parallel effects were also found due to subcutaneous rump fat depth and eye muscle area, which were highly correlated with each other and body condition score (r = 0.7-0.8). Liveweight differed from average by 1.65-1.66% per mm of rump fat depth and 0.71-0.76% per cm(2) of eye muscle area (P<0.01). Estimated dry matter digestibility of pasture consumed had no consistent effect in predicting liveweight and was therefore excluded from final models. A method developed to estimate full liveweight of post-weaning age female beef cattle from the other measures taken predicted liveweight to within 10 and 23% of that recorded for 65 and 95% of cases, respectively. For a 95% chance of predicted group average liveweight (body condition score used) being within 5, 4, 3, 2 and 1% of actual group average liveweight required 23, 36, 62, 137 and 521 females, respectively, if precision and accuracy of measurements matches that used in the research. Non-pregnant Bos taurus female cattle were calculated to be 10-40% heavier than Brahmans at the same hip height and body condition, indicating a substantial conformational difference. The liveweight prediction method was applied to a validation population of 83 unrelated groups of cattle weighed in extensive commercial situations on 119 days over 18 months (20 917 assessments). Liveweight prediction in the validation population exceeded average recorded liveweight for weigh groups by an average of 19 kg (similar to 6%) demonstrating the difficulty of achieving accurate and precise animal measurements under extensive commercial grazing conditions.

Liveweight gain and feed intake of weaned Bali cattle fed a range of diets in Central Sulawesi, Indonesia

Three experiments were conducted to determine liveweight (W) gain and feed and water intake of weaned Bali cattle offered a range of feed types. In each experiment, 18 weaned entire male Bali cattle were allocated to three treatment groups in a completely randomised block design, with six replicates (animals) per treatment. The dietary treatments were: Experiment 1, native grass fed ad libitum, native grass supplemented with rice bran at 10 g dry matter (DM)/kg W.day and native grass supplemented with a mixture of rice bran and copra meal in equal proportions fed at 10 g DM/kg W.day; Experiment 2, elephant grass hay fed ad libitum, elephant grass supplemented with gliricidia at 10 g DM/kg W.day, and gliricidia fed ad libitum; and Experiment 3, corn stover fed ad libitum, corn stover supplemented with gliricidia at 10 g DM/kg W.day, and corn stover supplemented with rice bran/copra meal in equal amounts (w/w) at 10 g DM/kg W.day. Each experiment was 10 weeks in duration, consisting of a 2-week preliminary period for adaptation to diets and an 8-week experimental period for the measurement of W change, feed and water intake and digestibility of the diet. Growth rates of 6-12-month-old, entire male Bali cattle fed a range of local diets ranged from 0.10 and 0.40 kg/day. Lowest growth rates occurred when the cattle were given the basal diets of native grass (0.104 kg/day), elephant grass (0.174 kg/day) and corn stover (0.232 kg/day). With the addition of supplements such as rice bran, rice bran/copra meal or gliricidia to these basal diets liveweight gains increased to between 0.225 and 0.402 kg/day. Forage DM intake was reduced with these supplements by on average 22.6% while total DM intake was increased by an average of 10.5%. The growth rate on gliricidia alone was 0.269 kg/day and feed DM intake was 28.0 g/kg W.day. Water intake was not affected by supplement type or intake. In conclusion, inclusion of small quantities of locally available, high quality feed supplements provide small-holder farmers with the potential to increase growth rates of Bali calves from 0.1 to 0.2 kg/day, under prevailing feeding scenarios, to over 0.4 kg/day.

Persistence of orally administered Megasphaera elsdenii and Ruminococcus bromii in the rumen of beef cattle fed a high grain (barley) diet

When cattle are fed grain, acidotic ruminal conditions and decreased efficiency in starch utilisation can result from the rapid production and accumulation of lactic acid in the rumen. The efficacy of drenching cattle with Megasphaera elsdenii and Ruminococcus bromii to improve animal performance was investigated. A feedlot trial was undertaken with 80 Bos indicus crossbred steers (initial liveweight 347.1 (s.d. 31.7) kg) in 10 pens in a randomised complete block design. An empty-pen-buffer was maintained between treated (inoculated) and untreated (control) groups to avoid transfer of inoculant bacteria to the control steers. Inoculated steers were orally drenched with M. elsdenii YE34 and R. bromii YE282, and populations increased rapidly over 3-14 days. The steers were fed for a total of 70 days with commercial, barley-based, feedlot rations. High growth rates (1.91 kg per day) were achieved throughout the experiment in both the inoculated and control steers. Intakes averaged 21.3 g dry matter (DM) per kg liveweight per day. There was probably no acidosis achieved in this trial following challenge (i.e. no change in pH occurred). There were no differences in any production or carcass measurements between the control and inoculated steers overall. However, the control group acquired dense ruminal populations of M. elsdenii by Day 14, while R. bromii populations established at high densities within the first 2 weeks but then declined and were undetectable by Day 50. R. bromii appears to be only transiently dominant, and once its dominance waned, it appeared that Ruminobacter spp. established in the rumen. Ruminobacter spp. became dominant between 14 and 28 days in all the steers examined and persisted through to the end of the study. These Ruminobacter spp. may be of future interest in the development of probiotics for grain-fed cattle.

Prediction of mortality and conception rates of beef breeding cattle in northern Australia

In current simulation packages for the management of extensive beef-cattle enterprises, the relationships for the key biological rates (namely conception and mortality) are quite rudimentary. To better estimate these relationships, cohort-level data covering 17 100 cow-years from six sites across northern Australia were collated and analysed. Further validation data, from 7200 cow-years, were then used to test these relationships. Analytical problems included incomplete and non-standardised data, considerable levels of correlation among the 'independent' variables, and the close similarity of alternate possible models. In addition to formal statistical analyses of these data, the theoretical equations for predicting mortality and conception rates in the current simulation models were reviewed, and then reparameterised and recalibrated where appropriate. The final models explained up to 80% of the variation in the data. These are now proposed as more accurate and useful models to be used in the prediction of biological rates in simulation studies for northern Australia. © The State of Queensland (through the Department of Agriculture, Fisheries and Forestry) 2012. © CSIRO.

Effect of monensin inclusion in supplements for cattle consuming low quality tropical forage

A pen feeding study was carried out over 70 days to determine the effects of monensin (M) inclusion in two commercial supplements designed to provide different planes of nutrition to recently weaned steers. Thirty Bos indicus crossbred steers (191.4 +/- s.d. 7.1 kg) were individually fed a low quality pangola grass hay (57 g crude protein/kg DM; 497 g/kg DM digestibility) ad libitum (Control) with either a urea/molasses-based supplement of Rumevite Maxi-graze 60 Block (B), fed at 100 g/day, or grain-based Rumevite Weaner Pellets (WP), fed at 7.5 g/kg liveweight (W).day, both with and without M, viz. B, B+M, WP and WP+M, respectively. There were no significant interactions between supplement type and M inclusion for any measurement. Growth rates (main effects) averaged 0.17, 0.35 and 0.58 kg/day for the Control, B and WP supplements, respectively, with all means different (P < 0.05), while the response (P < 0.05) to M across supplement type was 0.11 kg/day. Hay DM intake was similar for the Control and B treatments (18.6 and 19.6 g/kg W.day) but was reduced (P < 0.05) with the WP supplement (16.8 g/kg W.day) while corresponding total DM intakes increased from 18.6 to 20.0 to 23.5 g/kg W.day (all differences P < 0.05), respectively. Monensin inclusion in the supplements did not affect supplement, hay or total DM intake. Inclusion of of M in supplements for grazing weaners in northern Australia may increase survival rates although the effect of M with cattle at liveweight maintenance or below requires further investigation.

Multi-trait assessment of early-in-life female, male and genomic measures for use in genetic selection to improve female reproductive performance of Brahman cattle

Early-in-life female and male measures with potential to be practical genetic indicators were chosen from earlier analyses and examined together with genomic measures for multi-trait use to improve female reproduction of Brahman cattle. Combinations of measures were evaluated on the genetic gains expected from selection of sires and dams for each of age at puberty (AGECL, i.e. first observation of a corpus luteum), lactation anoestrous interval in 3-year-old cows (LAI), and lifetime annual weaning rate (LAWR, i.e. the weaning rate of cows based on the number of annual matings they experienced over six possible matings). Selection was on an index of comparable records for each combination. Selection intensities were less than theoretically possible but assumed a concerted selection effort was able to be made across the Brahman breed. The results suggested that substantial genetic gains could be possible but need to be confirmed in other data. The estimated increase in LAWR in 10 years, for combinations without or with genomic measures, ranged from 8 to 12 calves weaned per 100 cows from selection of sires, and from 12 to 15 calves weaned per 100 cows from selection of sires and dams. Corresponding reductions in LAI were 60-103 days or 94-136 days, and those for AGECL were 95-125 or 141-176 days, respectively. Coat score (a measure of the sleekness or wooliness of the coat) and hip height in females, and preputial eversion and liveweight in males, were measures that may warrant wider recording for Brahman female reproduction genetic evaluation. Pregnancy-test outcomes from Matings 1 and 2 also should be recorded. Percentage normal sperm may be important to record for reducing LAI and scrotal size and serum insulin-like growth factor-I concentration in heifers at 18 months for reducing AGECL. Use of a genomic estimated breeding value (EBV) in combination with other measures added to genetic gains, especially at genomic EBV accuracies of 40%. Accuracies of genomic EBVs needed to approach 60% for the genomic EBV to be the most important contributor to gains in the combinations of measures studied.