Use of partial mixed rations in pasture-based dairying in temperate regions of Australia

2013 ◽  
Vol 53 (11) ◽  
pp. 1167 ◽  
Author(s):  
W. J. Wales ◽  
L. C. Marett ◽  
J. S. Greenwood ◽  
M. M. Wright ◽  
J. B. Thornhill ◽  
...  

There is a growing diversity and complexity of dairy farming systems in Australia. Feeding systems based on the provision of mixed rations to dairy cows grazing perennial pastures (termed partial mixed rations or PMR systems) have emerged and present the dairy industry with opportunities for improved production and feed efficiency, but also with significant challenges. Early research results are beginning to define the situations in which PMR systems are profitable and the mechanisms responsible for the improved milk responses. This review focuses on the role of PMR feeding systems in temperate dairying regions of Australia, highlights initial research findings, and identifies some of the gaps in current knowledge that warrant further research. The key findings were that, when very low allowances of pasture are offered to cows, milk production responses were driven mostly by increases in dry matter (DM) intake, and there appeared to be a minimal contribution to increased energy supply from improved whole tract DM digestibility. Differences in milk responses became apparent when >10 kg of total supplement DM was consumed (0.75 : 0.25 concentrate to forage) as PMR. There was a consistent maintenance of milk fat concentration when increasing amounts of concentrates were consumed as PMR, in contrast with supplements consumed in the dairy. There was also a consistent finding that replacing some wheat in the PMR with canola meal resulted in cows consuming more grazed pasture despite the limitations of very low pasture allowances (10–15 kg DM/cow.day, expressed to ground level). This was accompanied by further increases in energy-corrected milk yield. The potential to improve DM intake was further highlighted when pasture allowance was increased, with intake increasing from 3.6% to 4.5% of liveweight (from 20 to 25 kg DM/day for a 550-kg cow). There was also an indication that ~50% of the milk production benefit from PMR can be captured by providing the concentrate supplement as a grain mix in the dairy. There did not appear to be negative impacts of PMR systems on the social and grazing behaviour or health of cows.

2017 ◽  
Vol 57 (7) ◽  
pp. 1305 ◽  
Author(s):  
M. J. Auldist ◽  
M. M. Wright ◽  
L. C. Marett ◽  
J. L. Jacobs ◽  
W. J. Wales

Milk production was measured in Holstein–Friesian cows offered low, medium or high allowances of ryegrass pasture (15, 25 or 40 kg DM/cow.day to ground level) and receiving different amounts of supplement (6, 10, 12 or 14 kg DM/cow.day) as a partial mixed ration (PMR). The 27-day experiment was conducted in spring when cows were 45 ± 17.3 days in milk (mean ± s.d.). Two groups of six cows received each of the 12 combinations of pasture allowance and PMR amount. The PMR comprised wheat grain (38%, DM basis), maize grain (18%), lucerne hay (22%) and canola meal (22%). When 6 kg DM PMR/cow.day was offered, cows grazing the low allowance produced less milk and energy-corrected milk than did cows grazing the medium and high allowances. There was no effect of pasture allowance on production of milk or energy-corrected milk at any other amount of PMR offered. When cows were offered 14 kg DM PMR/cow.day, milk fat concentrations were lower for cows grazing the high pasture allowance than for cows grazing the medium allowance. There were no differences in milk fat concentrations between cows grazing the different pasture allowances at any other amount of PMR offered. When cows were offered 6 kg DM PMR/cow.day, cows grazing the low pasture allowance yielded less milk fat than did cows grazing the medium pasture allowance. Cows grazing the high allowance had greater concentrations and yields of milk protein than did cows grazing the low allowance at all amounts of PMR offered, while cows grazing the medium allowance yielded more milk protein at some amounts of PMR. Pasture utilisation decreased with increases in both pasture allowance and amount of PMR. These results will enable farmers to better optimise feeding systems that combine both pasture and PMR.


2014 ◽  
Vol 54 (7) ◽  
pp. 869 ◽  
Author(s):  
M. J. Auldist ◽  
L. C. Marett ◽  
J. S. Greenwood ◽  
M. M. Wright ◽  
M. Hannah ◽  
...  

Milk production responses were measured in grazing cows offered supplements in different ways. Holstein–Friesian cows averaging 70 days in milk were allocated into 20 groups of eight, each including one rumen-fistulated cow. One of three dietary treatments was then randomly assigned to each of the 20 groups. Treatments were (1) Control (8 groups), where cows were supplemented with rolled wheat grain fed twice daily in the dairy and pasture silage provided in the paddock; (2) partial mixed ration (PMR; 8 groups), where cows were offered a PMR comprising rolled wheat grain, maize grain, maize silage and lucerne hay, which was presented on a feedpad immediately after each milking; the PMR was formulated to provide the same estimated metabolisable energy intake as the Control supplements; and (3) PMR+Canola (4 groups), where cows were fed in the same way as the PMR cows, except that a proportion of the wheat in the PMR was replaced with solvent-extracted canola meal. This ration was formulated to provide the same metabolisable energy as the Control and PMR treatments, but had greater amounts of crude protein. For Control and PMR treatments, supplements were offered at 8, 10, 12 or 14 kg DM/cow.day (2 groups per amount) while for the PMR+Canola treatment supplement was offered at 12 or 14 kg DM/cow.day (2 groups per amount). In addition to their supplements, all groups grazed an allowance of ~14 kg DM/cow.day (measured to ground level) of perennial ryegrass pasture. Yields of energy-corrected milk increased linearly with increasing supplement intake, but there was no difference between Control and PMR cows. When canola meal was added to the PMR, there was an increase in energy-corrected milk at a predicted supplement intake of 13.0 kg DM/cow.day. This was associated with a greater concentration and yield of milk fat in the PMR+Canola cows. Ruminal fluid pH and DM intake from pasture were also greater in PMR+Canola cows. It is concluded that farmers feeding high amounts of supplements to grazing cows could increase milk production by carefully considering the composition and form of the supplement mix, including the inclusion of canola meal.


2019 ◽  
Vol 59 (4) ◽  
pp. 778 ◽  
Author(s):  
M. J. Auldist ◽  
M. M. Wright ◽  
L. C. Marett ◽  
M. C. Hannah ◽  
E. Kennedy ◽  
...  

Milk production responses were measured in grazing cows offered mixed rations with or without canola meal. Experiments were conducted in spring (Experiment 1; early lactation) and autumn (Experiment 2; late lactation). The experiments used 140 (Experiment 1) or 96 (Experiment 2) Holstein-Friesian multiparous dairy cows that had calved in late winter/early spring. Each experiment lasted 28 days including a 14-day adjustment period and a 14-day measurement period during which intake and milk production was measured. In each experiment, there were two dietary treatments: PMR: cows grazed a restricted pasture allowance (10–15 kg DM/cow per day, measured to ground level) supplemented with a PMR comprising wheat grain (60%, DM basis), lucerne hay (21%) and maize grain (19%); and PMR+C: cows were fed the same as the PMR cows, but some wheat grain in the PMR was replaced with solvent-extracted canola meal so that it comprised wheat grain (39%, DM basis), lucerne hay (21%), maize grain (19%) and canola meal (21%). The two treatments were randomly allocated to half the cows in each experiment. Cows were then further allocated into 10 groups of 7 cows (Experiment 1) or 8 groups of 6 cows (Experiment 2). Two groups of cows were assigned to receive a different amount of each ration: 8, 10, 12, 14 or 16 kg DM total supplement/cow per day for Experiment 1 and 6, 8, 10 or 12 kg DM total supplement/cow per day for Experiment 2. In Experiment 1, yields of energy corrected milk (ECM), milk fat, and milk protein were greater for PMR+C cows than PMR cows when 12 kg/cow per day of supplement or more was offered. Milk protein concentration was greater in PMR+C cows than PMR cows but only when 16 kg DM supplement/cow per day was offered. These changes in milk yield and composition were associated with increases in the intakes of pasture, supplement and total DM intake in the PMR+C cows compared with the PMR cows. In Experiment 2 there were no differences in milk yield or composition between PMR and PMR+C cows at any amount of supplement offered, nor were there any differences in intakes of pasture, supplement or total DM intake. It is concluded that replacing some of the wheat in a well-formulated PMR with canola meal can stimulate DMI and increase per-cow production of ECM when high amounts of supplement are fed in early lactation, but not late lactation.


1995 ◽  
Vol 75 (4) ◽  
pp. 625-629 ◽  
Author(s):  
R. R. Corbett ◽  
L. A. Goonewardene ◽  
E. K. Okine

The effect of substituting peas for soybean and canola meals as a protein source in a high-producing dairy herd was studied in 66 Holstein cows, divided into two groups based on stage of lactation, parity, level of milk production and days in milk. Two 18.5% crude protein grain concentrate diets were formulated based on the nutrient analyses of the forages available. The control grain mix contained standard protein sources, principally soybean and canola meal (SBM\CM) while the test grain mix was formulated to contain approximately 25% field peas as the major source of protein. Both grain rations were formulated to the same nutrient specifications and balanced for undegradable protein. The duration of the trial was 6 mo during which grain feeding levels were adjusted monthly based on milk yield. For cows in early lactation, 4% fat-corrected milk yield was higher (P < 0.05) for cows fed pea based concentrates (31.3 kg d−1) than for cows fed SBM\CM supplement (29.7 kg d−1). Fat-corrected milk yield was not affected by source of protein in mid- and late-lactation cows. Fat-corrected milk production was not different (P > 0.05) for cows fed SBM\CM compared with cows fed the pea supplement when cows across all stages of lactation were included in the analyses. Milk fat percent was significantly higher (P < 0.05) for early- and mid-lactation cows fed the pea supplement. The results suggest that peas can be substituted for SBM\CM as a protein source for high-producing dairy cows. Key words: Dairy cow, pea, soybean and canola meal supplement, undegradable protein, milk production


2017 ◽  
Vol 84 (3) ◽  
pp. 240-247 ◽  
Author(s):  
Ruairi P McDonnell ◽  
Martin vH Staines

This research paper describes the effect of partially replacing wheat with maize grain and canola meal on milk production and body condition changes in early lactation Holstein-Friesian dairy cows consuming a grass silage-based diet over an 83-d period. Two groups of 39 cows were stratified for age, parity, historical milk yield and days in milk (DIM), and offered one of two treatment diets. The first treatment (CON) reflected a typical diet used by Western Australian dairy producers in summer and comprised (kg DM/cow per d); 8 kg of annual ryegrass silage, 6 kg of crushed wheat (provided once daily in a mixed ration), 3·6 kg of crushed lupins (provided in the milking parlour in two daily portions) and ad libitum lucerne haylage. The second treatment diet (COMP) was identical except the 6 kg of crushed wheat was replaced by 6 kg of a more complex concentrate mix (27% crushed wheat, 34% maize grain and 37% canola meal). Lucerne haylage was provided independently in the paddock to all cows, and no pasture was available throughout the experiment. The COMP group had a greater mean overall daily intake (22·5vs20·4 kg DM/cow) and a higher energy corrected milk (ECM) yield (29·2vs27·1 kg/cow;P= 0·047) than the CON cows. The difference in overall intake was caused by a higher daily intake of lucerne haylage in COMP cows (4·5vs2·3 kg DM/cow). The CON group had a higher concentration of milk fat (42·1vs39·3 g/kg;P= 0·029) than COMP cows. Milk protein yield was greater in COMP cows (P< 0·021); however, milk fat yield was unaffected by treatment. It is concluded that partially replacing wheat with canola meal and maize grain in a grass silage-based diet increases voluntary DMI of conserved forage and consequently yields of ECM and milk protein.


1987 ◽  
Vol 27 (1) ◽  
pp. 41
Author(s):  
RC Dobos ◽  
WJ Fulkerson ◽  
PJ Michell

Two herds, each of 19 Friesian cows, were run on separate farmlets in north-western Tasmania. One herd (NW) grazed pasture only, and was estimated to be receiving 75% of potential intake, while the second herd (W) received 3.0 kg coarsely hammermilled wheat per cow, daily for 42 days during early lactation in addition to pasture. Although the feeding of wheat increased total feed intake, there was no significant difference between the groups in either daily milk yield (21.5 v. 21.8 L cow-1), milk fat yield (1.1 v. 1.09 kg cow-1), liveweight change (0.05 v. -0.2 kg cow-l) and herbage intake (12.0 v. 12.0 kg DM cow-1 day-1) of cows or of pre- (1.77 v. 1.8 t DM ha-1) and post- (1.31 v. 1.32 t DM ha-1) grazing mass, on farmlets NW and W respectively. We conclude that the feeding of wheat did not increase milk production or improve liveweight change under the conditions of this experiment.


1977 ◽  
Vol 17 (89) ◽  
pp. 892 ◽  
Author(s):  
TH Stobbs

The short-term effects of varying the quantities of herbage allocated (15, 25, 35, 55 kg DM cow-1, day-1) to lactating Jersey cows strip grazing 3-week regrowths of nitrogen-fertilized Panicum maximum cv. Gatton panic pastures, upon the diet selected, milk production, milk and milk fat composition and grazing time, were measured. Sixteen cows were used in a latin-square design with experimental periods of 1 4 days. With increasing herbage allowance milk yields rose, averaging 8.9, 9.9, 10.4 and 10.6 kg milk cow-1, day-1 respectively. A lower solids-not-fat percentage in milk from cows receiving 15 kg DM cow-1, day-1 and a lower percentage protein from cows receiving 15 and 25 kg DM cow-1 day-1 indicated a lower intake of digestible energy by cows at these lower herbage allowances. Molar percentages of short-chain fatty acids in milkfat (C6, C8, C10, C14) increased linearly and oleic acid (C18:1) decreased linearly as herbage allowance increased, showing that a higher proportion of the milk fat was coming from energy in the feed and a smaller proportion from body reserves. Cows selectively grazed leaf from the uppermost layers of the swards. As herbage allowance was restricted, a higher proportion of pasture was eaten and this came mainly from pasture growing 10 cm or more above ground level. Total time spent grazing was similar for all herbage allowances but the proportion of night grazing was consistently lower at the higher intensities of grazing.


2019 ◽  
Vol 7 (2) ◽  
pp. 173-181
Author(s):  
Frances C. Cowley ◽  
Romana Roschinsky

Keynote paper presented at the International Leucaena Conference, 1‒3 November 2018, Brisbane, Queensland, Australia.The integration of leucaena into goat production systems in the tropics and subtropics is reviewed. Goats are well adapted to leucaena, and able to be productive on diets containing up to 100% leucaena as a result of bacterial and hepatic detoxification. Incorporation of leucaena into goat production systems can improve liveweight gains, milk production, worm control and reproduction. Successful feeding systems for goats can be based on both grazed silvopastoral systems and cut-and-carry intensive systems, although there is a lack of farming systems research examining the integration of leucaena into goat production systems, or documentation of the practicalities of these practices.


2000 ◽  
Vol 40 (7) ◽  
pp. 923 ◽  
Author(s):  
W. J. Wales ◽  
D. W. Dellow ◽  
P. T. Doyle

Two experiments were undertaken in summer to investigate production responses by dairy cows offered paspalum (Paspalum dilatatum Poir.)-dominant irrigated pasture to the inclusion of protein supplements with different rumen degradable protein characteristics in cereal grain-based concentrates. In experiment 1, cows in mid lactation were offered limited amounts of herbage, at an allowance of 28 kg DM/cow. day together with 8.0 kg DM/cow. day of a pelleted supplement containing: (i) mainly barley and wheat; (ii) barley, wheat and canola meal; or (iii) barley, wheat and cottonseed meal for 35 days. The 3 supplements were formulated to have similar in vitro DM digestibilities. In experiment 2 aspects of rumen function were measured in 9 rumen fistulated lactating cows, individually fed indoors on paspalum-dominant herbage harvested daily with a finger bar mower. Cows were offered the same amount of supplements for 28 days. Pasture intakes were similar to those of the grazing cows in experiment 1. In experiment 1, there were no effects (P>0.05) of dietary treatment on herbage intake (10.2 kg DM/cow. day) or selection of nutrients from herbage. The concentration of crude protein in the total diet consumed was lower (P<0.05) for the barley + wheat treatment (137 g/kg DM), compared with the barley + wheat + canola meal and barley + wheat + cottonseed meal treatments, which were 179 and 183 g/kg DM, respectively. In vitro DM digestibility of the feed consumed by cows was similar across the treatments, and all diets contained greater than 400 g neutral detergent fibre/kg DM, indicating there were no limitations due to dietary fibre. There were no significant effects (P>0.05) of dietary treatments on milk production (21.8 kg/cow. day), milk fat concentration (34.1 g/kg) or milk protein concentration (29.8 g/kg). Urea-N was higher (P<0.01) in the milk of cows fed the barley + wheat + canola meal and the barley + wheat + cottonseed meal treatments compared with the barley + wheat treatment. In experiment 2, rumen fluid pH was higher in cows consuming barley + wheat pellets than in cows consuming barley + wheat + canola meal on most sampling occasions. Rumen ammonia-N concentration was lowest in the barley + wheat treatment and highest in the barley + wheat + canola meal treatment. When cows grazing paspalum-dominant irrigated pasture were supplemented with 8 kg DM of a cereal-based supplement, metabolisable protein was calculated to be present in sufficient quantities to support at least 22 kg milk/cow. day and, hence, was not limiting milk production. It is concluded that protein supplements offered to cows in mid-lactation, grazing irrigated pastures in summer, are unlikely to give a milk production response beyond that achieved with cereal grain.


2019 ◽  
Vol 59 (5) ◽  
pp. 891 ◽  
Author(s):  
P. J. Moate ◽  
S. R. O. Williams ◽  
M. H. Deighton ◽  
M. C. Hannah ◽  
B. E. Ribaux ◽  
...  

There has been little research that has quantified methane (CH4) yields when dairy cows consume diets containing wheat grain. Furthermore, although rumen-fistulated animals have been used in many experiments concerned with measuring CH4 emissions, no research has examined the effect of rumen fistulation on in vivo CH4 emissions and yield. This experiment examined the effects of including either wheat or corn grain in the diet and the effects of rumen fistulation on yields of milk and milk components, CH4 emissions, yields, and intensities. Eight rumen-fistulated and six non-fistulated Holstein dairy cows in late lactation were offered a wheat-based diet (WHT) and a corn-based diet (CRN) in a crossover design. For the WHT diet, cows were offered daily, 22.4 kg DM containing 45.5% lucerne hay, 8.9% canola meal, 0.5% mineral mix, 0.5% molasses powder and 44.6% rolled wheat. The CRN diet was similar to the WHT diet except that rolled corn replaced the wheat. There was no difference between the WHT and CRN diets on mean milk yields (27.8 vs 27.9 kg/day), but the WHT diet substantially reduced milk fat concentration (2.76 vs 4.23%) and milk fat yield (0.77 vs 1.18 kg/day). Methane emissions (218 vs 424 g/day), CH4 yield (11.1 vs 19.5 g/kg dry matter intake) and CH4 intensity (7.6 vs 15.7 g/kg milk) were all reduced ~45% by the WHT diet compared with the CRN diet. Rumen fistulation did not affect dry matter intake, milk production, milk composition or CH4 emissions, but decreased CH4 yield and intensity. Including wheat in the diet of dairy cows has the potential to be an effective strategy to reduce their greenhouse gas emissions. In addition, rumen fistulation was associated with a small reduction in CH4 yield and intensity, and this should be considered when using rumen-fistulated cows in research concerned with CH4 emissions.


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