Dry matter intake and nutrient selection by lactating cows grazing irrigated pastures at different pasture allowances in summer and autumn

1998 ◽  
Vol 38 (5) ◽  
pp. 451 ◽  
Author(s):  
W. J. Wales ◽  
P. T. Doyle ◽  
D. W. Dellow

Summary. Three experiments investigating the effects of herbage allowance on the consumption of nutrients by lactating cows were conducted on irrigated perennial pastures in northern Victoria during summer and autumn. Experiment 1 was conducted in mid lactation (autumn–early winter) with perennial ryegrass [54% of dry matter (DM)]–white clover (22% of DM) pasture offered at allowances of 15, 20, 30 and 40 kg DM/cow.day. Herbage intake increased (P<0.001) from 8.0 to 14.6 kg DM/cow.day as allowance increased and this was associated with a decrease (P<0.001) in utilisation from 54 to 37%. The cows consistently selected a diet 11% higher in in vitro dry matter digestibility than that in the pasture on offer, but selection for crude protein increased (P<0.001) from 21 to 41% above that in herbage on offer as herbage allowance increased. Neutral detergent fibre content of the diet selected was lower (P<0.001) than that in herbage on offer. Along with these changes, milk production increased (P<0.001) from 9.0 to 15.5 kg/day as herbage allowance increased at a marginal response of 0.99 kg milk/kg extra DM consumed. Experiments 2 and 3 were conducted in mid lactation (summer) on pasture containing 28% paspalum, 26% weeds, 17% perennial ryegrass or 36% paspalum, 19% weeds and 24% ryegrass respectively. Pasture allowances were between 20 and 70 kg DM/cow.day. Herbage intake increased (P<0.001) from about 8 to 17 kg DM/cow.day as allowance increased in both experiments and was accompanied by a decrease (P<0.001) in utilisation from about 40 to less than 25%. In experiment 2, the cows consistently selected a diet with a similar in vitro dry matter digestibility to that of the herbage pregrazing, regardless of allowance, but selection for crude protein increased (P<0.05) from 25 to 45% above that in herbage on offer, as allowance increased. In experiment 3, the diet selected was 13% greater (P<0.001) in in vitro dry matter digestibility and 42% greater (P<0.001) in crude protein than the herbage on offer. Neutral detergent fibre content of the diet selected was lower (P<0.001) than that in herbage on offer in experiment 3, while the difference was small in experiment 2. Along with these changes, milk production increased (P<0.001) (in experiment 2, 12.3–15.0 kg/cow.day; experiment 3, 10.0–15.8 kg/cow.day) as herbage allowance increased, but the marginal responses were lower (0.28 kg milk/kg extra DM consumed in experiment 2, 0.64 kg milk/kg extra DM consumed in experiment 3) than observed in experiment 1 reflecting the differences in pasture quality.

1999 ◽  
Vol 39 (8) ◽  
pp. 923 ◽  
Author(s):  
P. J. Moate ◽  
D. E. Dalley ◽  
J. R. Roche ◽  
C. Grainger

Summary. The effect of herbage allowance (20, 30, 40, 50, 60 and 70 kg DM/cow. day) on the consumption of nutrients from herbage and milk production by cows in early lactation, was examined. The experiment was conducted on rainfed perennial ryegrass pastures in September and October 1997 in south-eastern Victoria, Australia. The herbage on offer comprised 64% perennial ryegrass, 21% other grasses, 1% white clover, 5% weeds and 9% dead material on a dry matter (DM) basis. The average pregrazing herbage height was 13 cm, at an estimated pregrazing herbage mass of 3.6 t DM/ha. The herbage on offer was of high quality containing 11.6 MJ metabolisable energy/kg DM, 202 g crude protein/kg DM and 525 g neutral detergent fibre/kg DM. Concentrations of calcium, magnesium, sodium, potassium, phosphorus, sulfur and chloride were 4.4, 2.2, 4.4, 31.2, 3.5, 2.7 and 11.4 g/kg DM, respectively. As daily herbage allowance per cow increased, dry matter intake increased curvilinearly (P<0.01) from 11.2 to 18.7 kg DM/cow. day. This was associated with a decrease in utilisation of herbage from 54 to 26% and an increase in milk production from 25.9 to 29.1 kg/cow. day. The cows on all treatments grazed for less than 8.7 h/day. The increase in intake was achieved by an increase in the rate of herbage intake from 1.5 to 2.2 kg DM/h for herbage allowances of 20 and 70 kg/cow.day, respectively. Irrespective of herbage allowance, cows selected a diet that was approximately 10% higher in in vitro dry matter digestibility and 30% higher in crude protein than that in the herbage on offer. The neutral detergent fibre content of the herbage selected was lower (P<0.05) than that on offer. The herbage consumed contained more (P<0.05) magnesium, potassium and sulfur, the same amount of calcium and phosphorus and less (P<0.05) sodium and chloride than the herbage on offer. For rainfed perennial pastures in spring, herbage allowance is an important factor in determining voluntary feed intake and production of dairy cows. To achieve 30 L from herbage, without supplementation, high herbage allowances are required. The increase in herbage intake, with increasing herbage allowance, resulted from an increase in rate of dry matter intake and not an increase in grazing time. No relationship was evident between herbage allowance and the selection differentials for in vitro dry matter digestibility, crude protein and neutral detergent fibre. Selection differentials for rainfed perennial pastures in spring are similar to those reported for irrigated perennial pastures in northern Victoria in spring and autumn. When determining nutrient requirements it is important to consider the interaction between herbage intake and nutrient concentration in the herbage.


1999 ◽  
Vol 39 (6) ◽  
pp. 645 ◽  
Author(s):  
W. J. Wales ◽  
P. T. Doyle ◽  
D. W. Dellow

Summary The nylon bag technique was used to estimate the degradability of the dry matter (DM) and crude protein (CP) of herbage samples and supplementary feeds from recent grazing experiments with dairy cows conducted in Victoria. The cumulative disappearance data for CP were used to calculate the effective rumen degradability of CP (ERDP, g/kg DM) for these feeds at rumen outflow rates of 0.02, 0.05 or 0.08/h. Crude protein was more extensively degraded than DM in all herbage samples collected before grazing, or in those samples taken to represent the herbage consumed by grazing cows. The ERDP of spring pastures (excluding the dead material and postgrazed samples) was generally in the range 103–197 g/kg DM, at an outflow rate of 0.02/h and in the range 74–142 g/kg DM, at an outflow rate of 0.08/h. For summer pastures, the ERDP was generally in the range 80–128 g/kg DM, at an outflow rate of 0.02/h and in the range 58–108 g/kg DM, at an outflow rate of 0.08/h. For autumn pastures, ERDP ranged from 108 to 170 g/kg DM, at an outflow rate of 0.02/h and from 84 to 140 g/kg DM, at an outflow rate of 0.08/h. There were only 2 herbage samples collected during the winter, which had ERDP of 237 and 249 g/kg DM, at an outflow rate of 0.02/h and 213 and 222 g/kg DM, at an outflow rate of 0.08/h. Values for ERDP tended to be higher for these winter samples compared with spring samples. In contrast, autumn samples tended to have lower ERDP than spring samples. It is shown that metabolisable protein is unlikely to limit milk production of cows consuming 17 kg herbage DM/cow. day and producing up to 30 L milk/day, when milk production is determined from metabolisable energy supply. The excesses in metabolisable protein ranged from 0.48 to 1.21 kg/cow. day from a subset of spring herbage samples cut to represent that selected by cows and from 0.14 to 0.23 kg/cow. day from summer herbage samples. The degradability characteristics of the herbage samples were similar to some estimates for temperate herbages in the United Kingdom and from limited data from Australia and should form a useful basis on which to assess whether additional metabolisable protein is required as supplements for dairy cows grazing pastures in Victoria. There was a positive (P<0.01) relationship between CP content and ERDP (R2 = 0.93), across herbage samples indicating it could be possible to estimate ERDP for herbage samples that have been assessed for CP content. There was also a significant (P<0.01) positive relationship between the effective degradability of DM of herbage and ERDP (R2 = 0.77). The relationships between in vitro dry matter digestibility or neutral detergent fibre and ERDP were also significant (P<0.01), but accounted for even less of the variability. The ERDP in cereal grain-based supplements ranged from 87 to 111 g/kg DM, at a outflow rate from the rumen of 0.02/h, compared with 70–92 g/kg DM, at an outflow rate of 0.08/h. The compounded supplements containing varying levels of cereal grain, lupins and cottonseed meal, had effective degradabilities of CP that generally declined as the content of lupins decreased and the content of cottonseed meal increased. However, ERDP increased to 152 g/kg DM because of the increasing CP content with increasing cottonseed meal. These results are compared with previously published estimates of effective degradability of CP for supplementary feeds.


2000 ◽  
Vol 40 (1) ◽  
pp. 1 ◽  
Author(s):  
W. J. Wales ◽  
D. W. Dellow ◽  
P. T. Doyle ◽  
A. R. Egan

Two experiments were undertaken to investigate responses by dairy cows grazing irrigated perennial pastures in autumn to supplementation with barley grain and pasture hay. Cows in late lactation were offered limited amounts of perennial ryegrass–white clover pasture at 26 kg DM/cow. day. Supplements were offered as nil or 6.0 kg DM/cow.day plus perennial pasture hay at 0, 0.5, 1.2, 2.0 or 3.0 kg DM/cow. day in a replicated experiment with 6 treatments using 36 cows (3 cows/treatment replication). The second experiment, which was conducted concurrently with experiment 1, measured aspects of rumen function and blood parameters in 3 groups of 3 rumen fistulated lactating cows grazing at the same herbage allowance and supplemented with barley (6.0 kg DM/cow. day) and 0, 1.0 or 3.0 kg DM of pasture hay daily. The in vitro DM digestibility and crude protein and neutral detergent fibre content of the barley and perennial pasture hay was 863 and 640 g/kg DM, 134 and 87 g/kg DM and 192 and 615 g/kg DM, respectively. In experiment 1, the cows from all treatments consumed herbage (mean s.d.) with an in vitro DM digestibility of 811 21.8 g/kg DM, crude protein content of 233 26.0 g/kg DM and neutral detergent fibre content of 404 39.4 g/kg DM compared with the pregrazed herbage on offer of 710, 152 and 526 g/kg DM, respectively. The mean pregrazing herbage mass of 3.75 t DM/ha in experiment 1 consisted of perennial ryegrass (580 g/kg DM), white clover (100 g/kg DM), weeds (110 g/kg DM) and dead material (210 g/kg DM). Without supplements, cows consumed 10.0 kg DM/day of this pasture with a neutral detergent fibre intake of 4.43 kg/day. The herbage grazed in experiment 2 was similar. Herbage intake did not decline to a large degree when barley was included in the diet indicating a very low substitution rate under the prevailing conditions where herbage allowance was only 26 kg DM/cow. day. Inclusion of hay progressively decreased (P<0.05) herbage intake, with substitution averaging 1.2 kg DM of herbage/kg DM of hay. Total DM intakes (15.5 kg DM/cow. day) were similar for the barley and the barley plus hay treatments up to 2.0 kg DM hay/cow. day; total DM intake was higher (P<0.05) for the 3.0 kg hay treatment. Milk production increased (P<0.05) with grain and hay supplementation, the marginal response being 0.8–1.0 kg milk/kg DM supplement, however, there was no significant difference between the 5 supplemented treatments. Supplementation with hay had no significant effect (P>0.05) on milk fat or milk protein contents which averaged 44.6 and 35.2 g/kg milk, respectively. The ratio of acetate + butyrate:propionate was 4.1:1 when cows consumed 6.0 kg barley, which was around the critical ratio of 4:1 for milk fat of 40 g/kg. Increasing the amount of hay in the diet did not alter this ratio. Because of the high levels of substitution of hay for pasture, changes in neutral detergent fibre intake were small between supplemented treatments. The rumen pH, ammonia-N concentration and volatile fatty acid concentration were relatively stable during the day because of a relatively slow rate of eating (1.5 kg DM/h) and long rumination time (about 6.8 h/day). Ruminal pH was rarely below 6.0, even when barley was given alone, suggesting that fibre digestion was not compromised. Additional fibre as supplemental hay to cows in late lactation grazing irrigated pasture did not improve milk production when the neutral detergent fibre content of the diet was above an average of 336 g/kg DM. Use of hay as a means of providing additional fibre could reduce herbage utilisation.


2015 ◽  
Vol 54 (1) ◽  
pp. 31-40 ◽  
Author(s):  
G. A. Burns ◽  
P. O’Kiely ◽  
D. Grogan ◽  
S. Watson ◽  
T. J. Gilliland

Abstract This study examined 169 of the newest varieties of three ryegrass species, perennial (Lolium perenne L.), Italian (Lolium multiflorum Lam.) and hybrid (Lolium boucheanum Kunth), from Recommended List trials in Ireland. The traits examined were yield, dry matter concentration, three nutritive value traits (in vitro dry matter digestibility, water-soluble carbohydrate on a dry matter basis and crude protein concentration) and two ensilability traits (buffering capacity and water soluble carbohydrate concentration on an aqueous phase basis). Varietal monocultures of each species underwent a six cut combined simulated grazing and silage management in each of two years following sowing. Perennial ryegrass yielded less than both other species in one-year-old swards, but less than only Italian ryegrass in two-year-old swards, but generally had the higher in vitro dry matter digestibility and crude protein values. Italian ryegrass displayed the most favourable ensilability characteristics of the three species with perennial ryegrass less favourable and hybrid ryegrass intermediate. Overall, despite the high yields and favourable nutritive value and ensilability traits recorded, the general differences between the three ryegrass species studied were in line with industry expectations. These findings justify assessing the nutritive value and ensilability of ryegrass species, in addition to yield, to allow farmers select species that match farming enterprise requirements.


2001 ◽  
Vol 41 (4) ◽  
pp. 465 ◽  
Author(s):  
W. J. Wales ◽  
Y. J. Williams ◽  
P. T. Doyle

An experiment was undertaken to establish the marginal milk production response from cereal grain supplementation by dairy cows grazing irrigated perennial pastures in spring and whether the addition of a hay supplement would improve that response. Cows were offered perennial ryegrass (Lolium perenne L.)–white clover (Trifolium repensL.) pasture at allowances (measured to ground level) of 20 or 40 kg dry matter (DM)/cow.day. Additional cows offered the low allowance were also offered supplements of pasture hay as a cube or pellet (2.5 kg DM/day), cereal grain as a pellet (5.0 kg DM/day) or cereal grain plus pasture hay (7.5 kg DM/day) as a pellet (1.75:1 DM basis) or cube (1.97:1 DM basis). The 7 treatments were replicated 3 times, and 63 cows were used (3 cows/treatment). The in vitro DM digestibility, crude protein and neutral detergent fibre (NDF) concentration of the barley and perennial pasture hay were 863 and 563 g/kg DM, 131 and 92 g/kg DM, and 182 and 666 g/kg DM, respectively. Cows from all treatments consumed herbage with an in vitro DM digestibility of 833 g/kg DM, crude protein content of 214 g/kg DM and NDF concentration of 457 g/kg DM compared with the pregrazed herbage on offer of 771, 174 and 527 g/kg DM, respectively. The mean pregrazing herbage mass of 4.13 t DM/ha consisted of perennial ryegrass (507 g/kg DM), white clover (188 g/kg DM), weeds (194 g/kg DM) and dead material (111 g/kg DM). Without supplements, cows consumed 11.2 kg DM/day at the low pasture allowance and 15.6 kg DM/day at the high allowance. Herbage intake did not decline to a large degree when barley was included in the diet, where a substitution rate of 0.2 kg reduction in pasture DM/kg DM cereal grain supplement was measured. The NDF concentration of the diet consumed was lowest (P< 0.05) for the grain pellet treatment (370 g NDF/kg DM) and highest (P&lt;0.05) for the fibre pellet (493 g NDF/kg DM) and the fibre cube (507 g NDF/kg DM) treatments. Fat-corrected milk yield increased (P<0.05)) from 20.1 to 24.5 kg/cow.day when cows consumed 4.5 kg DM cereal grain/day with a marginal milk response of 1.0 kg 4% fat-corrected milk/kg DM concentrate supplement. Supplementation with grain or hay had no significant effect (P>0.05) on milk fat, protein or lactose concentrations. The cows offered the high allowance spent more (P<0.05) time grazing than those offered the low allowance, but there were no significant differences in rumination time. Cows spent more time ruminating when consuming the grain &plus; fibre cube compared with the other supplement treatments, which were lower (P<0.05) and similar. Cows offered pasture at the low allowance ruminated the least. The rumen pH was not different between treatments and averaged 5.9. The ratio of acetate plus butyrate: propionate was not different between treatments and averaged 4.3. This study has shown that feeding cereal grain to cows grazing pastures high in perennial ryegrass resulted in acceptable marginal milk responses of 1 kg milk/kg DM of cereal grain in spring because of sufficient NDF in the diet. As there was adequate NDF in the diet, further supplements with pasture hay as cubes or pellets had no effect on marginal milk responses .


Crop Science ◽  
1986 ◽  
Vol 26 (6) ◽  
pp. 1123-1126 ◽  
Author(s):  
N. J. Ehlke ◽  
M. D. Casler ◽  
P. N. Drolsom ◽  
J. S. Shenk

1972 ◽  
Vol 52 (6) ◽  
pp. 941-948 ◽  
Author(s):  
L. B. MacLEOD ◽  
H. T. KUNELIUS ◽  
F. W. CALDER

The effects of early summer and fall cutting managements on two alfalfa (Medicago sativa L.) cultivars were studied over a 3-year period. Removal of the first crop of Saranac and Narrangansett alfalfas at prebud stage, followed by two cuts at the early bloom stage before early September, and a late fall harvest on October 25, produced seasonal dry matter (DM) yields of 7.5–8.6 metric T/ha in the 1st year. Stand deterioration, however, was severe and by the 3rd year, practically all alfalfa had disappeared. Average percent crude protein (CP) in cut 1 was 17.7–21.9 and percent in vitro dry matter digestibility (IVD) 67.4–73.8. Removal of the first cut at bud stage with two subsequent harvests at the early bloom stage also allowed a total of three harvests before early September and resulted in seasonal DM yields of 8.6–8.8 in the 1st year. Although the survival of alfalfa was increased over the managements where cut 1 was at prebud stage, a considerable decrease of alfalfa was still observed in the 3rd year. Under this management, average CP in cut 1 was 15.8–16.3 and IVD 64.1–68.4. Harvesting the first crop at early to midbloom stage and the second crop at early bloom in early to mid-August, followed by third harvest in late October, resulted in good survival with seasonal DM yields of 6.1–10.6. Lower CP and IVD were recorded in cut 1 than in the more intensive managements. Under all managements, average CP in cuts 2 and 3 was 14.9–17.3 and 13.3–19.4, respectively. IVD was 54.5–60.7 in cut 2 and 56.0–64.4 in cut 3.


1992 ◽  
Vol 1 (5) ◽  
pp. 491-497
Author(s):  
Abate Tedla ◽  
Helena Airaksinen ◽  
M. A. Mohamed-Saleem

The influence of the improved drainage broadbed and furrow (BBF), as opposed to the traditional flat seedbed over the growing season on the dry matter yield and nutritive value of Avena sativa, Vigna unguiculata, Lablab purpureus, Vida dasycarpa, Trifolium steudneri and Sesbania sesban were studied on Vertisol. Up to 7 t/ha dry matter yield was recorded for Avena sativa and Lablab purpureus when planted on Vertisols with improved drainage. Dry matter yield of forage crops also increased with advance in stage of maturity or subsequent harvests. On both improved and traditional flat seedbed methods, the chemical analysis of forage crops showed similar declines in crude protein content and in vitro dry matter digestibility (IVDMD) levels as the maturity of forage crops progressed.


2018 ◽  
Vol 53 (9) ◽  
pp. 1045-1052
Author(s):  
Mateus Merlo Coelho ◽  
Lúcio Carlos Gonçalves ◽  
José Avelino Santos Rodrigues ◽  
Kelly Moura Keller ◽  
Gustavo Vinícius de Souza dos Anjos ◽  
...  

Abstract: The objective of this work was to evaluate the effects of re-ensiling and bacterial inoculation on the quality of corn silage. The experiment was carried out in a 2x2 factorial design with or without inoculant (association of Lactobacillus plantarum and Propionibacterium acidipropionici), and with re-ensiling after 36 hours of aerobic exposure or only ensiling of the whole plant of 'BRS 1055' corn. The fermentative quality, nutritional parameters, dry matter losses, aerobic stability, and microbiological counts of silages were evaluated. Re-ensiling caused an increase of pH and in acetic acid and propionic acid concentrations, as well as in the dry matter (DM), crude protein, neutral detergent fiber, and neutral detergent fiber crude protein contents. Conversely, there was a reduction in the nonfiber carbohydrates concentration and in in vitro dry matter digestibility for the re-ensiled material. All changes were explained by the higher-effluent production and DM loss of re-ensiled material that was subjected to two compactions. Microbiology was not altered by the treatments. The use of inoculant altered ash content, but it did not influence other parameters. In contrast, re-ensiling after 36 hours of aerobic exposure caused a reduction in the nutritive value of corn silage and accentuated the DM losses.


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