Diet selection and liveweight performance of steers on Stylosanthes hamata-native grass pastures

1980 ◽  
Vol 31 (2) ◽  
pp. 379 ◽  
Author(s):  
CJ Gardener

Diet selection in S. hamata-native grass pastures was studied over 25 months at Lansdown, north Queensland, In oesophageally fistulated steers. The results were uscd to interpret the relationship between winter rainfall and liveweight gain of steers on pastures with and without S. hamata. Steers selected green grass leaf early in the wet season (December-February), but preferred S. hamata in March when stem elongation and flowering occurred in the native grasses. They then continued to eat a high proportion of legume during the dry season until rain fell. At Lansdown, this may occur from 4 to 23 weeks after the pastures hay off. After the rain, the steers ignored the large bulk of mouldy dry legume, selecting instead both green and dry grass. Seed and green leaf of S. hamata made their greatest contribution to the diet at the end of the wet season when retained on the standing plant and easily accessible to cattle. Small amounts of seed and dried leaf were licked off the ground before rain fell. The nitrogen content of the diet in the S. hamata-native grass pastures rose to a peak in April and did not fall below 1.0% during the study. The level in July was twice that recorded for the native pasture. Cattle gained weight during the wet season at a similar rate for all pastures. After March steers on S. hamata-native pasture continued to gain weight longer onto the dry season than those on native pasture in three out of four years. Much of the additional weight gains of steers on S. hamata were lost with the advent of winter rain, especially at the high stocking rate from which the perennial grass component had been lost. The value of S. hamata cv. Verano in the greatly differing climatic environments existing in northern Australia is considered.

1988 ◽  
Vol 28 (6) ◽  
pp. 669 ◽  
Author(s):  
WH Winter

Native perennial grass pastures were oversown with Stylosanthes hamata cv. Verano at 3 fertility levels, i.e, without fertiliser or with suboptimal levels of superphosphate or rock phosphate. Brahman steers, of varying ages, grazed the pastures and their responses to fertility level and direct supplementation with phosphorus and sulfur were determined over 4 years. Phosphorus supplementation doubled liveweight gains during the early and late wet season periods to about 0.9 and 0-7 kg/day, respectively. Pasture fertility level did not affect gains in the early wet season in most years but superphosphate increased the late wet season gains by about 0.1 kg/day. Small weight losses usually occurred in all treatments during the early dry season, with losses increasing with animal age. Weight losses were highest during the late dry season, particularly for the older, phosphorus supplemented, steers. This response was attributed to size rather than to age or supplementation per se. Sulfur supplementation had no effect upon liveweight gain or upon the pastures at any time. In unfertilised pastures, Verano increased to about 25% of the dry matter composition whilst pastures fertilised with superphosphate and rock phosphate became legume dominant after 2 and 3 years, respectively. Fertiliser also increased the nitrogen, phosphorus and sulfur concentrations in the forage, particularly the Verano, with superphosphate more effective than rock phosphate. In pastures where steers were supplemented with phosphorus there was a higher proportion of the naturalised legume Alysicarpus vaginalis and a lesser quantity of forage on offer. Blood inorganic phosphate and rib cortical thickness were reliable indicators of responsiveness of steers to phosphorus supplementation when measured during, or immediately after, the period of active growth.


1996 ◽  
Vol 36 (7) ◽  
pp. 781 ◽  
Author(s):  
DB Coates

The dietary preference of cattle grazing Stylosanthes-based pastures in the seasonally dry tropics of North Queensland was studied using faecal carbon ratios (S13C) to determine grass-legume proportions. Estimates were made at monthly intervals for several years in 1 experiment to determine the effect of year, season and botanical composition on dietary stylo proportions. In another experiment, the effect of stylo cultivars (Verano and Seca) on dietary preference was monitored for 17 months. Where pastures provided ample opportunity for selection, cattle showed a strong preference for grass in the early wet season and in the late dry season. The proportion of stylo in the diet increased during the wet season and reached peak proportions (as high as 80%) in the late wet season or early dry season. Dietary stylo proportions decreased as pastures dried off and as the stylo shed leaf or became more stemmy. The length of the wet season and the amount and distribution of rainfall had a major influence on the seasonal pattern of diet selection. Stylo rarely fell below 20% in the diet. On an annual basis, stylo accounted for about 45% of the diet which was appreciably higher than the proportion of stylo in the pasture. Dietary stylo proportions were higher on Seca-based pasture than on Verano-based pasture. The avoidance of stylo in the early wet season was less pronounced with Seca compared with Verano. Later in the season Seca was the dominant dietary component for a much longer period than Verano. The effect of botanical composition on dietary grass-legume proportions varied between and within years. Correlations between grass-legume proportions in the pasture and in the diet were highest in the late dry season and early wet season when preference for grass was strongest. At the end of the wet season when cattle preferred stylo, dietary stylo was not related to pasture stylo content except in a drought year. Averaged over the full year, dietary stylo content was significantly correlated with pasture stylo content in all years and the correlation was highest in a drought year when there was a high level of utilisation and less opportunity for selection. A simple model relating dietary stylo to pasture stylo was developed and is discussed.


1983 ◽  
Vol 23 (120) ◽  
pp. 4 ◽  
Author(s):  
RG Holroyd ◽  
PK O'Rourke ◽  
MR Clarke ◽  
ID Loxton

The reproductive performance of cows and growth rate of their calves to weaning was examined over a four-year period (1973-1977). Cows grazed either native pasture stocked at 1cowl4 ha, or native pasture oversown with Townsville stylo (Stylosanthes humilis) and fertilized with superphosphate stocked at 1 cow/2 ha. Animals were supplemented on each pasture type with urea-molasses in the dry season, phosphorus all year round plus urea-molasses in the dry season, or were unsupplemented. Mating was for three months from mid-January. Calving began towards the end of the dry season and cows lactated through the following wet season. Cows grazing fertilized legume pasture had significantly higher conception rates and earlier calving dates in one year only. In all years, foetal and calf losses between pregnancy diagnosis and weaning were lower on native pasture than on fertilized legume pasture. Cows grazing fertilized legume pasture were generally in better body condition and heavier throughout and their calves grew faster to weaning than on native pasture. Fertilized legume pasture produced a 2.4 fold increase over that of native pasture in cow and calf liveweight per unit area (382.7 kg/ha vs 159.8 kg/ha) over the four years. Supplementation did not influence liveweight or reproductive performance of cows or calf growth rate except during the final dry season when non-supplemented cows lost significantly more weight than those supplemented with phosphorus and urea.


1993 ◽  
Vol 33 (5) ◽  
pp. 571 ◽  
Author(s):  
MR McCaskill ◽  
JG McIvor

Data from a long-term grazing experiment were used to develop relationships suitable for modelling between-year variation in pasture and animal production. The experiment was conducted near Townsville in North Queensland and consisted of a factorial combination of 2 stocking rates (0.6, 1.2 steers/ha) x 2 pasture types (native pasture, native pasture plus Stylosanthes hamata cv. Verano) x 2 superphosphate rates (nil, 300 kg/ha.year). Cattle were weighed monthly, and the herbage presentation yield and stylo content estimated annually. Relationships between annual liveweight gain (LWG) and a range of climate-derived parameters including the number of 'green days' were calculated from a water balance and pasture growth model. When a different intercept was allowed for each pasture and stocking rate combination, there was a strong relationship between annual LWG and the number of 'green days' (R2 = 0.78). In a more general relationship, LWG was related to green days, stylo content, and utilisation rate (R2 = 0.58). No relationships was found that would enable reliable prediction of between-year variation in the pasture attributes of stylo content and the water use efficiency of herbage growth. The times of the year when daily rates of LWG changed could be predicted satisfactorily, but rate of gain within each phase varied considerably from year to year. Differences in LWG between stocking rates occurred when there would have been restricted amounts of new green feed, or of stylo in the late wet season.


1977 ◽  
Vol 17 (85) ◽  
pp. 197 ◽  
Author(s):  
RG Holroyd ◽  
PJ Allan ◽  
PK O'Rourke

A study was made over a four year period ( 1970-1 973) on the reproductive performance of cows grazing either native pasture stocked at 1 breeder 4.9 ha-1 or native pasture oversown with Townsville stylo (Stylosanthes humilis) and fertilized with superphosphate, stocked at 1 breeder 2.4 ha-1. Animals were supplemented on each pasture type with combinations of molasses, urea and phosphorus at various times of the year. Mating from September 1 to January 31 resulted in animals lactating during the dry season. At double the stocking rate, lactating cows on fertilized pastures had similar conception rates to those on native pasture. During a prolonged dry season, lactating cows on fertilized pasture had twice the conception rate and fewer required survival feeding. Urea compared with non-urea based supplements produced significant increases in conception rates of cows grazing native pasture especially during a dry year. Calves were born earlier, had shorter intercalving intervals and fewer cows had to be fed a survival ration when urea was available. On fertilized pasture, urea based supplements caused only a marginal increase in conception rate except in a dry year, when there was a significant increase. Over the four years, there was a diminishing response in the conception rate of lactating cows grazing native pasture and supplemented with phosphorus during the wet season compared with the control. On fertilized pasture, there was a variable but non-significant response. The addition of phosphorus either as a wet or dry season supplement to urea caused variable responses on each pasture type, but none differed significantly from that of urea.


1977 ◽  
Vol 17 (86) ◽  
pp. 357 ◽  
Author(s):  
L Winks ◽  
FC Lamberth ◽  
PK O'Rourke

The effect of phosphorus supplementation on the performance of steeres grazing unfertilized native pasture and Townsville stylo (Stylosanthes humilis) with andwithout superphosphate fertilizer on the subcoastal spear grass region of the dry tropics of north Queensland was studied over a period of 40 months. Liveweight gains in the absence of supplementation on fertilized Townsville stylo pastures were greater than on unfertilized Townsville stylo, where performance was similar to that recorded on untreated native pasture. Phosphorus supplementation increased weight gains during the wet season on both unfertilized Townsville stylo and native pasture but had no significant effect on dry season performance or performance on fertilized Townsville stylo. Fertilized areas became dominated by annual grasses, Digitaria ciliaris and Brachiaria milliiformis, and legume yields were higher on unfertilized than on fertilized areas. Fertilizer improved the quality of available pastures.


1998 ◽  
Vol 38 (1) ◽  
pp. 7 ◽  
Author(s):  
D. B. Coates ◽  
R. P. Le Feuvre

Summary. The effect of phosphorus (P) on diet selection in cattle grazing pastures based on Stylosanthes hamata cv. Verano andS. scabra cv. Seca in the seasonally dry tropics was studied in 3 grazing trials on soils with inherently low P status ( 5 µg/g bicarbonate-extractable P). The contribution of Stylosanthes (stylo) to diets was estimated at regular intervals (approximately monthly) using carbon isotope analysis of faeces. Feeding P supplement increased the proportion of stylo in the diet but the effect was seasonal and variable, being most pronounced during the late wet and early dry seasons when dietary stylo proportions are usually highest. The results indicated that P supplement influenced diet selection through its effect on dietary P status such that cattle with a deficiency of dietary P select a lower proportion of stylo than those with higher P intakes. The effect of fertiliser P on dietary stylo content was also variable. The dominant effect was via fertiliser-induced changes in pasture botanical composition. Higher stylo proportions in the diet of heifers grazing unfertilised pasture compared with those grazing fertilised pasture were associated with increasing stylo dominance in unfertilised pastures as opposed to grass dominance in fertilised pastures. At the same time there was evidence of a fertiliser treatment effect that was consistent with dietary P status influencing diet composition. In the grass-dominant pastures, unsupplemented cattle on low P pasture selected less stylo than those grazing pastures of higher P status due to more frequent fertilising but there was no difference where P supplement was fed. A strong seasonal preference for grass early in the wet season, reinforced by a generally reduced preference for stylo in cattle with diets deficient in P, probably hastened the development of stylo dominance in unfertilised pasture where P supplement was not fed.


1985 ◽  
Vol 25 (1) ◽  
pp. 61 ◽  
Author(s):  
JG McIvor

Six Urochloa accessions (U. mosambicensis cv. Nixon, CPI 46876, CPI 47 167 and U. oligotricha CPI45607, CPI47122, CPI 47 124) were grown with Stylosanthes hamata cv. Verano and S. scabra cv. Seca in individually fenced, fertilized swards near Townsville, Queensland, for 5 years. The swards were grazed by single steers for 2 days at 6-weekly intervals (equivalent to a stocking rate of 1 steedha). Two grazing regimes were used: grazing throughout the year (high grazing pressure); and grazing during the dry season only (low grazing pressure). There was good establishment of Verano but Seca and all Urochloa accessions established poorly. In subsequent years there were few U. oligotricha seedlings but there were substantial numbers of U. mosambicensis seedlings. Most seedlings died during their first year and in the final year of the study the number of perennial Urochloa plants ranged from 1 /m2 (CPI 47 122) to 1 7/m2 (CPI 46876). Yield and proportion of Urochloa were low during the first year but later increased for the U. mosambicensis accessions, particularly CPI 46876, which out-yielded all other accessions in the final 3 years. High yields of Urochloa were associated with low yields of Verano and annual grasses. High grazing pressure reduced the total pasture yield. Verano was always a major component, especially at high grazing pressure. The proportion of Seca increased from an initial low level but then declined again to a very low level. There was very little native perennial grass at high grazing pressure. The proportion of grass in the swards was highest at the start of the wet season and then declined; in contrast, the proportion of legume increased during the wet season. The value of Urochloa species in seasonally dry tropical areas and their management in pastures are discussed.


1970 ◽  
Vol 74 (3) ◽  
pp. 487-494 ◽  
Author(s):  
R. J. Haggar

SUMMARYChanges in yield and quality of an Andropogon gayanus sward were traced throughout the 1964 wet season and part of the following dry season.Quality, in terms of crude-protein content, was highest at the beginning of the wet season, but yield increased to a maximum at the beginning of the dry season. Once flowering was completed in October, herbage quality fell to a very low level. It was concluded that the best time to cut for hay was in early October, at which time the crude-protein content showed a small but significant increase. Regrowth measurements taken in mid-November indicated the benefit of taking an early hay cut in July as a means of producing better quality hay at the end of the rains.During the early vegetative phase of growth leaf production was greater than stem production. Quality was high because the leaves contained a higher content of crudeprotein, calcium, phosphorus and carotene than the stems. During the reproductive stage of growth, comprising stem elongation in September culminating in anthesis in early October, quality was lower due to the high fibre content of the stems. The increase in crude-protein in early October, coincided with the expansion of new leaves on the flowering stems.It was concluded that throughout most of the latter part of the growing season A. gayanus did not provide adequate supplies of crude-protein, calcium and particularly phosphorus for normal cattle growth, especially after flowering was completed in late October.


1979 ◽  
Vol 19 (98) ◽  
pp. 325 ◽  
Author(s):  
P Gillard

The results of a grazing experiment in which Townsville stylo was oversown into native pasture in sub-coastal northern Queensland are reported. The region receives 650 mm average annual rainfall compared with >850 mm at other experimental sites where Townsville stylo has been tested under grazing. The experiment included three treatments in a factorial combination: timber clearing or not, application of 125 kg ha-1 superphosphate or not and stocking rates of 0.4 and 0.2 beasts ha-1. The yield of Townsville stylo depended on treatments and annual rainfall but was generally low in this environment. Over the ten year period of the experiment the pastures remained dominated by Heteropogon contortus and Bothriochloa bladhii, and there was no invasion of annual grasses. Clearing of the timber increased the pasture yield by 77%. There was no regrowth of trees after clearing. Within each year cattle gained weight in the wet season, when pasture quality was high, and lost weight in the dry season, when pasture quality declined. Mean liveweight gain over all treatments was correlated (r = 0.97) with the length of the growing season. A significant response in liveweight gain to fertilizer occurred only in years of average or above rainfall when there was also a response in Townsville stylo yield. The effect was due to increased gains during the wet season; there were no differences in liveweight gain during the dry season, when Townsville stylo became decomposed. Significantly greater liveweight losses occurred on the heavily stocked treatments during the dry season of drought years. The yield of Townsville stylo in the early years of the experiment was significantly higher on the cleared treatments and there was a corresponding response in liveweight gains in the wet season during this period. Liveweight losses in the dry season were also significantly higher on the timbered treatments in years of drought. The powerful influence of climatic variation on the treatments places reservations on their practical application. The increased pasture yield from tree clearing is likely to be a benefit to cattle only in years of drought. The responses to superphosphate fertilizer only in years of high rainfall suggests that its use is unlikely to be profitable on Townsville stylo based pastures in this environment.


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