Rearing of dairy cattle 6. The effect of length of grazing rotation on animal and herbage production in a grazing system for calves and heifers

1975 ◽  
Vol 21 (2) ◽  
pp. 157-164 ◽  
Author(s):  
J. D. Leaver

SUMMARYA rigid system of grazing management was examined for 2 years using rotations of fixed length. Rotations of 21 and 35 days were compared at low (3 calves+ 3 heifers/ha) and high (4 calves+ 4 heifers/ha) stocking rates. The calves and heifers grazed the paddocks on a leader/follower basis.Average growth rates for the 21- and 35-day rotations were respectively 0·75 and 0·78 for calves and 0·78 and 0·83 kg/day for heifers, but these differences were not significant. The 35-day rotation produced 6% more live-weight gain and 4% more herbage dry matter/ha than the 21-day rotation. The high stocking rate produced 14% more live-weight gain but 3% less herbage dry matter/ha than the low stocking rate. The total percentage utilization of herbage dry matter for the whole season was similar for 35- and 21-day rotations, averaging 90%. There were no significant interactions between length of rotation and stocking rate.

1981 ◽  
Vol 97 (2) ◽  
pp. 353-364 ◽  
Author(s):  
S. E. Watson ◽  
P. C. Whiteman

SummaryAnimal production was compared on three pastures, Brachiaria mutica (para), B. decumbens (signal) and Panicum maximum cv. Hamil (hamil) each sown with a common legume mixture of Centrosemapubescens (centro), Macroptilium atropurpureum cv. Siratro, and Stylosanthes guianensis cv. Endeavour (stylo), at four stocking rates, 1·8, 21·87, 31·86, and 41·85 animals/ha, over 4 years on the GuadalcanalPlains, Solomon Islands.Mean live-weight gain per head over the four stocking rates and 4 years on para pastures was 01·847, on signal pastures 01·838, and on hamil pastures 01·828 kg/head/day. Mean production per hectare at the optimum stocking rates were: para at 3.6 animals/ha, 607 kg; signal at 31·86 animals/ha, 442 kg; hamil at 21·87 animals/ha, 362 kg/ha/year.The high stocking rates of 31·86 and 41·85 animals/ha caused the hamil pastures to decline to the stage where they were destocked in the 4th year of grazing.Superior production on para pastures was not simply related to green dry matter (GDM) on offer. In the 1st year of grazing, GDM was highest in hamil pastures, but in the 2nd year highest in para, and in the 3rd year mean yields were similar in all pastures, but were very low at the 31·86 and 41·85 animals/ha stocking rate in the hamil pastures.Para pastures maintained highest legume contents. The quadratic relationship between live-weight gain/head and legume content was significant over all pastures and stocking rates. Live-weight gain (LWG) per head increased up to 15% legume content, after which there was little change. Yield of green leaf, percentage green leaf, and sward bulk density did not appear to be related to LWG/head. Para pastures had lower values for all these components than the other pastures.Chemical factors contributed to the higher animal production from para pastures. Para leaf maintained consistently higher in vitro dry-matter digestibility values. Na content of para averaged 01·812%, whereas other species were 01·801 to 01·802%, and below the critical level (01·805%) for animal intake. N and S in leaf material, and Cu in total tops were also consistently higher in para grass.Results of this grazing trial suggest that selection of grass species on the basis of quality including dry-matter digestibility and mineral content, on ability to persist with increasing stocking rate, on compatibility with legumes, and on growth habit are more important than selection for dry-matter yield.


1974 ◽  
Vol 18 (3) ◽  
pp. 273-284 ◽  
Author(s):  
J. D. Leaver

SUMMARYA rotational system of grazing, in which Friesian calves grazed the paddock immediately in front of a group consisting of pregnant and non-pregnant young female cattle (heifers), was examined at stocking rates initially of 3·0, 3·5 and 4·0 replacement units per ha (a replacement unit = one calf + one heifer). The stocking rates were reduced towards the end of the season by removing pregnant heifers. Measurements were made of live-weight gains and herbage production and utilization. Increasing the stocking rate from 3·0 to 4·0 units/ha depressed live-weight gain in calves by 18% on average and in heifers by 32%. The stocking rate of 3·5 replacement units/ha produced the greatest amount of live-weight gain per ha. There was a progressive decline in herbage production and consequently live-weight gain from early to late season. Herbage production was also depressed by the increased stocking rate. Although the average utilization of herbage at each grazing was low, ranging from 27 to 37% in calves and 35 to 48% in heifers, the total utilization of herbage over the whole season was high, ranging from 88 to 96%.


1981 ◽  
Vol 97 (3) ◽  
pp. 669-676 ◽  
Author(s):  
S. E. Watson ◽  
P. C. Whiteman

SUMMARYA grazing study, comparing a naturalized and a sown pasture at three stocking rates, was conducted under a uniform stand of 65-year-old coconuts on a fertile soil in the Russell Islands. In a plot trial on this site there was no significant response to application of up to 400 kg N/ha/year over 2 years to Brachiaria decumbens. Average daily transmission of photosynthetically active radiation through the coconut canopy was 60% of full sunlight. The sown pasture consisted initially of para (Brachiaria mutica), signal (B. decumbens) and koronivia (B. humidicola) with the legumes Centrosema pubescens, Pueraria phaseoloides and Stylosanthes guianensis. The main species in the naturalized pasture were Axonopus compressus, Mimosa pudica, C. pubescens and Colopogonium mucunoides. Pastures were set stocked in two replicates over 3 years at 1·5, 2·5 and 3·5 animals/ha. There was no significant difference in live-weight gain between pastures in any year. Live-weight gain per head declined linearly with increasing stocking rate. Highest live-weight gain was 437 kg/ha/year in the 1st year at 3·5 animals/ha. The planted grasses declined from 60% at the start of grazing to 6% 8 months later. A. compressus increased from 2 to 24% over 3 years in the sown pasture, and from 12 to 34% of yield in the natural pasture. M. pudica increased from 27 to 44% in the sown, and remained approximately constant at 37% in the natural pasture. G. pubescens increased at 2·5 animals/ha, but was replaced by P. phaseoloides at 1·5 animals/ha and by A. compressus and M. pudica at 3·5 animals/ha. There were no significant effects of pasture treatments or stocking rate on copra yields. Where there is a cover of naturalized grasses and legumes under coconuts, cultivation and planting of exotic species cannot be recommended. Major improvement will come from thorough weed control and maintaining stocking rates between 1·5 and 2·5 animals/ha.


2021 ◽  
Vol 29 (1) ◽  
pp. 55-63
Author(s):  
O. S. Onifade ◽  
I. F. Adu ◽  
J. O. Akinola

Mixed pastures of Rhodes grass (Chloris gavana cv. Callide) and Stylo (Stylosanthes guianensis cv. Cook) were evaluated at five stocking rate, 12, 18, 24, 30 and 36 rams/ha over five grazing periods at Shika, Nigeria. The pastures were continuously grazed for 154 to 210 days beginning from late ruiny into dry season (August 10 April). Dry matter yields of stem, leaf, stem + leaf of C. gayana, green material and total herbage declined (P<0.01) as stocking rate and grazing days increased. However, the differences in yields of green material and leaf of C. Igayana at P4 and 30 rams/ha were not significant over the grazing periods. Daily live weight gain (g/headd) was negatively and linearly related to stocking rate. Mean live weight gains at the lowest and highest stocking rates were + 52 and -1 g/head/d in the second grazing season and 62 and 24 g/head/d in the fifth grazing period. Mean live weight production/ha and optimum stocking rates (OSR) in the first, second, third, fourth and fifth grazing periods were: 61.2kg, 17.8 sheep/ha; 155.5kg; 20.4 sheep/ha; 186.2kg, 24.9 sheep/ha; 129.4kg, 21.2 sheep/ha and 200.2kg, 26.0 sheep/ha, respectively. A curvilinear relationship was obtained between live weight gain ha and stocking rate. This study indicated that sheep at the highest and lowest stocking rates will need supplementary feeds after 100 and 128 days, respectively, if grazing commenced just before the end of the rain.


1982 ◽  
Vol 34 (2) ◽  
pp. 225-237 ◽  
Author(s):  
R. D. Baker ◽  
J. M. Barker ◽  
Y. L. P. Le Du

ABSTRACTForty-eight Hereford × Friesian cows and their South Devon calves were paddock grazed at high or low stocking rates of 412 or 206 cows and calves per ha in experiment 1, and either paddock grazed or set stocked at high or low stocking rates of 4·12 or 2·74 cows and calves per ha in experiments 2 to 4.There was no significant effect of grazing system on milk yield, milk composition or calf growth but in experiment 2 paddock-grazed cows gained more weight than those set stocked. Cows at low stocking rates gained more weight than those at high stocking rates and, in general, gave more milk. Calf growth rates were also higher at low stocking rates in experiments 1, 3 and 4 but not in experiment 2. Milk composition was not significantly affected by stocking rate. There were substantial increases in calf live-weight gain per ha at the high stocking rate but, because of a lower gain by cows, the differences in total live-weight gains per ha for cows and calves were much smaller.


1999 ◽  
Vol 21 (2) ◽  
pp. 199 ◽  
Author(s):  
D Freudenberger ◽  
A Wilson ◽  
R Palmer

A grazing study was conducted in a semi-arid mulga (Acacia aneura) woodland to determine the relative importance of variables controlling sheep production in this environment. The study was based on six sheep stocking rates (0.3-0.8 sheeplha) with the exclusion of other large herbivores including kangaroos and feral goats. The availability of forage and its components, together with the wool growth and live weight of the sheep were measured every three months for seven years from October 1986. Annual rainfall accounted for 60% of the annual variation in live weight gain per head and 79% of the variation in wool growth per head. Stocking rate accounted for an additional 10% of the variation. Rainfall accounted for this large proportion of variation by its strong influence on the yield of green leaf which accounted for 78% of the variation in live weight gain and 66% of the variation in wool growth. Green leaf was a determinant of sheep production because of its superior crude protein content and digestibility compared to dry leaf and stem. The species comprising this green leaf had an influence on sheep production only during drier years when the presence of palatable perennial grasses became important to sheep production. The frequency and yield of perennial grasses were greatly diminished at high stocking rates. This change in forage composition caused a decline in sheep productivity as detected by a loss of linearity in the relationship between stocking rate and live weight gainlhead. We conclude that adjusting stocking rates is required in this environment for maintenance of long-term sheep productivity and landscape function. The loss of palatable perennial C, grasses over much of the region has reduced livestock productivity and increased the variability in forage availability. Stock numbers should be adjusted at critical times to avoid losing perennial grasses that are important for sheep production in drier years. New grazing strategies are required to restore these grasses to the region.


1983 ◽  
Vol 100 (1) ◽  
pp. 139-148 ◽  
Author(s):  
J. L. F. Zoby ◽  
W. Holmes

SUMMARYTwenty-four Friesian cattle classed as large, medium or small and from 776 to 163 kg initial live weight (LW) were grazed over two successive 8-week periods. Two stocking rates were imposed and there were four replicates. Trios of animals, including one of each size, grazed in each paddock. Cattle changed stocking rate in mid-season. Herbage intake, live-weight gain and grazing behaviour were recorded.The stocking rates resulted in large differences in herbage allowance and consequent differences in intake, live-weight gain and grazing behaviour. The large cattle were least able to compensate for the higher stocking rate by increasing grazing time or frequency of biting. Average herbage organic-matter (OM) intakes ranged from 13 g OM/kg LW for large animals to 28 g OM/kg LW for the small animals.


1970 ◽  
Vol 75 (2) ◽  
pp. 265-272 ◽  
Author(s):  
J. D. Leaver

SUMMARYAn experimental and a conventional grazing system for 7- and 19-month-old dairy replacements were compared during 136 days of the grazing season. In the experimental system A, 24 calves were rotationally grazed around paddocks followed by 24 pregnant heifers which ate the herbage residue left by the calves. The conventional system B consisted of 24 calves and 24 pregnant heifers maintained at the same overall stocking rate as in system A, but the calves and heifers grazed in completely separate rotations. Half the calves on each system were drenched with an anthelmintic at weekly intervals from mid-July onwards to estimate within systems the effect of gastrointestinal worms on live-weight gain.


1981 ◽  
Vol 33 (3) ◽  
pp. 265-272 ◽  
Author(s):  
I. A. Dickson ◽  
J. Frame ◽  
D. P. Arnot

ABSTRACTDuring the period 1974-77 six blocks of a perennial ryegrass/white clover sward were each divided into two for rotational paddock-grazing and silage cutting in alternate years. For each use an annual total of 360 kg nitrogen per ha was applied. Six livestock treatments of cattle only or cattle and sheep were grazed on the blocks. The stocking rates per ha and combinations of cattle (yearling steers) and sheep (ewes nursing twin lambs) respectively were low, 7·5 + 0; medium, 10 + 0, 7·5 + 5, and 5+10; and high, 7·5 + 10 and 5 + 15.The annual quantities of herbage organic matter accumulated (6·6 to 7·2 t/ha) and consumed (5·6 to 6·7 t/ha) did not differ markedly according to grazing treatment during an individual year, nor was there an effect on organic matter accumulation in subsequent conservation years (11·3 to 12·0 t/ha). Between-year effects were significant. As judged by persistence of sown species there was no evidence of sward deterioration over the 4 years.Total live-weight gain per ha increased with increasing stocking rate but with a decreasing increment. The ranges were 106 to 1·42 t/ha within treatments, 102 to 1/45 t/ha within years and 0·97 to 1·8t/ha within treatments × years. Individual gains of cattle (0·67 to 0·88 kg/day) and lambs (0·20 to 0·27 kg/day), and the proportion of lambs ready for slaughter (0·53 to 0·97), were lowest at the highest stocking rate. Mixed grazing compared with cattle-only led to improved cattle gains and improved total gains per ha. The benefits of mixed grazing for a species tended to increase as the proportion of that species in the mix decreased.


1995 ◽  
Vol 60 (1) ◽  
pp. 75-80 ◽  
Author(s):  
I. Dufrasne ◽  
M. Gielen ◽  
P. Limbourg ◽  
C. van Eenaeme ◽  
L. Istasse

AbstractA comparison was made between two different finishing systems with Belgian Blue bulls. Two groups of bulls were grazed during an initial 140-day period and then finished indoors with concentrates. There were two stocking rates during the grazing period: a medium at six bulls per ha (MGFI) and a high at eight bulls per ha (HGFI). A third group of bulls was finished indoors on a concentrate diet during the whole finishing period (FI). The experiment was repeated over 2 years consecutively. The pasture which was grazed at the medium stocking rate was characterized by a higher sward height (P < 0·01), more refusals (P < 0·001), less Lolium perenne (P < 0·05) and more Trifolium repens (P<0·05) than that grazed at eight bulls per ha. The live-weight gain was 1·15 kg/day during the grazing period for the MGFI bulls and 1·00 kg/day when they were taken indoors. The increase in stocking rate reduced the gain at grass (1·00 kg/day, P < 0·001) and improved the gain indoors (1·24 v. 1·01 kg/day, P < 0·001). In the groups which were initially grazed when compared with the indoor system, the fattening period was longer (236·0 and 241·0 v. 186·9 days, P<0·01) and the live-weight gain lower (1·11 and 1·10 v. 1·44 kg/day, P < 0·001 for MGFI, HGFI and Fl respectively). The dressing proportion was greater also (P < 0·05), and there were higher concentrations of muscles (P < 0·05) and bones (P < 0·05) in the carcass of the bulls which were grazed initially. With these bulls, the lean meat was darker (P<0·05) and lost more water although there were no effects on the myoglobin content or on shear force. The net profit was in favour of the groups which were grazed.


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