Evaluating the economics of short-term partial mixed ration feeding decisions for dairy cows

2018 ◽  
Vol 58 (8) ◽  
pp. 1531 ◽  
Author(s):  
C. K. M. Ho ◽  
W. J. Wales ◽  
M. J. Auldist ◽  
B. Malcolm
Keyword(s):  
Milk Production ◽  
Control Diet ◽  
Canola Meal ◽  
Early Lactation ◽  
Short Term ◽  
Cereal Grain ◽  
Farm Profit ◽  
Tactical Decision ◽  
The Cost ◽  
Supplement Intake

Recent research in Australia has measured the marginal milk production responses of cows grazing perennial-based pastures to supplements offered as a partial mixed ration (PMR). In the present study, the milk responses to PMR feeding developed under a restricted pasture allowance were used to examine the contribution to farm profit of decisions about short-term feeding (weekly, monthly). A short-term, or tactical, decision was considered to be one where the infrastructure and equipment needed to mix and feed out a formulated ration were already available. The decision was, therefore, the choice of whether to feed supplements as grain in the dairy at milking and forage in the paddock, or to feed the supplements as a mixed ration on a feed pad. Both of these options were assumed to exist for the farmer decision-maker, with the comparison of rations being based solely on the costs of supplement and milk income. The Control diet in the experiments comprised cereal grain fed in the dairy and pasture silage fed in the paddock, simulating a situation where pasture available for grazing was limiting. The PMR diet consisted of cereal grain, maize grain, maize silage and lucerne hay combined in a mixer wagon and fed on a feed pad. The PMR + canola diet was similar to the PMR diet, but included canola meal. The profitability of the diets for different amounts of supplement intake was compared by estimating the total income from milk produced minus the cost of the supplements. The results indicated that feeding the diet comprising PMR plus canola meal in early lactation contributed more to farm profit than did the Control diet of feeding grain in the dairy and forage in the paddock, or PMR feeding without canola meal, because of higher milk production. At a supplement intake of 12 kg DM/cow.day, the PMR + canola diet added AU$0.97/cow.day and AU$2.11/cow.day more to profit than the Control and PMR without canola meal diets, respectively. For a farm already equipped with a feed pad and mixer wagon, the benefits of feeding a mixed ration exceed the costs in early lactation. In late lactation, each diet made similar contributions to farm profit because of similar milk production.

Evaluating the economics of concentrate feeding decisions in grazing dairy cows

2018 ◽  
Vol 58 (7) ◽  
pp. 1329 ◽  
Author(s):  
C. K. M. Ho ◽  
J. W. Heard ◽  
W. J. Wales ◽  
J. L. Jacobs ◽  
P. T. Doyle ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Milk Fat ◽  
Marginal Cost ◽  
Variable Cost ◽  
Significant Variable ◽  
Marginal Revenue ◽  
Short Term ◽  
Cereal Grain ◽  
Farm Profit

Purchased concentrates are a significant variable cost of a dairy business. Farm economic theory states that feeding supplements will enable a dairy farmer to improve profit as long as the marginal revenue received from the milk produced exceeds the marginal cost of the supplement. To do this, the quantities of milk, milk protein and milk fat produced from a unit of concentrate added to the diet are needed. Recent research has compiled results from short-term concentrate feeding experiments conducted in Victoria over a 30-year period. Using these data, relationships for the response of milk production to cereal grain supplements in dairy cows grazing temperate pastures have been developed and shown to be a better predictor than previous relationships. These response functions were used in the present study to investigate the economics of tactical (short-term; weekly, monthly or seasonally) and strategic (medium- to longer-term) supplementary feeding decisions in a pasture-based system, including, specifically, how much concentrate should be fed in a particular farm situation, given a certain feed cost and milk price. In the present paper, the relevant production economics method is explained and applied to determine the amount of supplement to feed that will maximise the margin of total extra milk income minus the total cost of supplement, thereby adding the most to farm profit. Currently, when dairy farmers make decisions about how much more supplement to feed their herd, they are making implicit judgements about the extra milk, and other potential benefits, that they expect to result as well as what the milk will be worth. More finely tuned decisions about feeding supplements based on comparing marginal cost and marginal revenue would add more to farm profit than decisions based on other common criteria, such as feeding supplement for maximum milk production. While some farmers may already be feeding supplements close to the point where marginal cost equals marginal revenue, the formal method of marginal analysis reported here makes explicit what is done implicitly at present and tests farmers’ intuitive decision-making. More detailed information about the responses to supplements and the costs and benefits of feeding supplements under particular circumstances at different times through the lactation has the potential to enable better, more profitable decisions to be made about feeding cows and managing the whole farm.

scholarly journals Effects of Feeding either Red or White Grape Marc on Milk Production and Methane Emissions from Early-Lactation Dairy Cows

Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 976 ◽  
Author(s):  
Peter J. Moate ◽  
Joe L. Jacobs ◽  
Josh L. Hixson ◽  
Matthew H. Deighton ◽  
Murray C. Hannah ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Perennial Ryegrass ◽  
Dry Matter ◽  
Control Diet ◽  
Methane Emissions ◽  
Partial Replacement ◽  
Early Lactation ◽  
Grape Marc ◽  
The Cost

Globally, annual production of grape marc (GM), the residue of skins, seeds and stems remaining after making wine, has been estimated to be approximately nine million tonnes. No previous studies have compared effects on milk production and methane emissions when GM from either red or white grapes was fed to dairy cows. This experiment examines the effects of partial replacement of a perennial ryegrass (Lolium perenne L.) based diet with GM from either red or white grapes on yield and composition of milk and methane emissions. Thirty-two Holstein dairy cows in early lactation were offered either a control diet containing 15.0 kg dry matter (DM) of freshly harvested perennial ryegrass and 5.2 kg of a concentrate mix, or a diet similar to the control diet but with 5 kg DM of ryegrass replaced with 5 kg DM of GM from red grapes (RGM), or a diet similar to the RGM diet except the GM was from white grapes (WGM). Individual cow feed intakes, milk yields, and methane emissions were measured. Both diets containing GM decreased milk yields by approximately 10% and methane emissions by 15%. When fed to dairy cows, GM reduces methane emissions but at the cost of decreased milk production.

Protected canola meal increases milk protein concentration in dairy cows fed a grass silage-based diet

2004 ◽  
Vol 44 (9) ◽  
pp. 827 ◽  
Author(s):  
C. L. White ◽  
M. v-H. Staines ◽  
N. Phillips ◽  
P. Young ◽  
F. Coupar ◽  
...  
Keyword(s):  
Milk Yield ◽  
Protein Concentration ◽  
Milk Protein ◽  
Control Diet ◽  
Subterranean Clover ◽  
Dietary Treatment ◽  
Canola Meal ◽  
Grass Silage ◽  
South West ◽  
Cereal Grain

Low concentrations of protein in milk occur during the summer–autumn in south-west Australia. This is the period, on dryland farms, when the diet of lactating cows typically consists of grass silage and a mixture of crushed lupins and cereal grain. This experiment was conducted to test the hypothesis that supplying protected canola meal would increase the protein concentration of milk and, possibly, milk yield in cows fed grass silage and a lupin–cereal concentrate. Sixty Holstein cows in mid lactation were allocated to 2 equal-sized dietary treatment groups: control (lupin) or protected canola meal. The control diet consisted of 14.5 kg DM grass silage (annual ryegrasses–subterranean clover) and 5.4 kg DM of crushed lupins and barley (4:1) per head per day. For the protected canola meal diet, 2.15 kg DM protected canola meal replaced 2.15 kg lupins. The protected canola meal was produced by treating solvent-extracted canola meal with formaldehyde, to produce a product with an in sacco fractional degradability of 0.29 at a rumen fractional outflow rate of 0.08/h. The equivalent degradability of untreated canola meal was 0.80 and of lupin was 0.83. Cows were individually fed the concentrate ration twice daily, after each milking, then were managed as a single herd in dry lots and fed grass silage. By the end of 8 weeks, cows fed the protected canola meal diet had higher milk protein concentrations (30.7 v. 29.2 g/L; P<0.05) and higher liveweights (604 v. 593 kg; P<0.05). Milk yield (L/day) was increased by 1 L/day, but this effect was not significant (P>0.10). Fat concentration was unaffected by diet (P>0.05). Since the only difference in treatment was the replacement of a portion of lupins with protected canola meal, the results indicate that a deficiency of metabolisable amino acids contributes to the low milk protein concentrations recorded during summer–autumn in south-west Australia. Whether this was acting primarily through a stimulus of appetite, or directly on milk components, could not be determined because silage intakes were not recorded.

scholarly journals Economic Analysis of Offering Different Herbage Allowances to Dairy Cows Fed a Partial Mixed Ration

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1704
Author(s):  
Christie K. M. Ho ◽  
Martin J. Auldist ◽  
Marlie M. Wright ◽  
Leah C. Marett ◽  
Bill Malcolm ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Dairy Cow ◽  
Early Lactation ◽  
Total Milk ◽  
Net Benefits ◽  
Grazing Dairy Cows ◽  
The Cost ◽  
Dairy Cow Nutrition ◽  
Feeding Systems

The economics of grazing dairy cows offered a range of herbage allowances and fed supplements as a partial mixed ration (PMR) were examined where profit was defined as the margin between total milk income and the cost of pasture plus PMR supplement. The analysis made use of milk production and feed intake data from two dairy cow nutrition experiments, one in early lactation and the other in late lactation. In early lactation and at a PMR intake of 6 kg DM/cow per day, the profit from the cows with access to a medium herbage allowance (25 kg DM/cow per day) was AUD 1.40/cow per day higher than that for cows on a low allowance (15 kg DM/cow per day). At a higher PMR intake of 14 kg DM/cow per day, the profit from the cows on a medium herbage allowance was AUD 0.45/cow per day higher than the cows on a low allowance; there was no additional profit from increasing the herbage allowance from medium to high (40 kg DM/cow per day). In late lactation, the profit from the cows fed a PMR with a medium herbage allowance (20 kg DM/cow per day) was only higher than the cows on a low allowance (12 kg DM/cow per day) when the PMR intake was between 6 and 12 kg DM/cow per day. There was also a difference of AUD +0.50/cow per day between the PMR with medium and high herbage allowance (32 kg DM/cow per day). It was concluded that farmers who feed a PMR to dairy cows should offer at least a medium herbage allowance to optimize profit. While feeding additional PMR increases milk production and profit, further gains would be available by offering a higher herbage allowance. These findings provide an estimate of the net benefits of different herbage allowances when feeding a PMR and will enable farmers to manage their feeding systems more profitably.

Protein supplementation of cows grazing limited amounts of paspalum (Paspalum dilatatum Poir.)-dominant irrigated pasture in mid-lactation

2000 ◽  
Vol 40 (7) ◽  
pp. 923 ◽  
Author(s):  
W. J. Wales ◽  
D. W. Dellow ◽  
P. T. Doyle
Keyword(s):  
Milk Production ◽  
Cottonseed Meal ◽  
Milk Fat ◽  
Rumen Fluid ◽  
Protein Supplementation ◽  
Canola Meal ◽  
Paspalum Dilatatum ◽  
Protein Supplements ◽  
Cereal Grain

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.

Effect of level of grain supplementation on milk production responses of dairy cows in mid - late lactation when grazing irrigated pastures high in paspalum (Paspalum dilatatum Poir.)

2001 ◽  
Vol 41 (1) ◽  
pp. 1 ◽  
Author(s):  
G. P. Walker ◽  
C. R. Stockdale ◽  
W. J. Wales ◽  
P. T. Doyle ◽  
D. W. Dellow
Keyword(s):  
Treatment Group ◽  
Dairy Cows ◽  
Milk Production ◽  
Milk Yield ◽  
Milk Fat ◽  
Rumen Fermentation ◽  
Paspalum Dilatatum ◽  
Cereal Grain ◽  
Diminishing Returns ◽  
Supplement Intake

Two grazing experiments tested the hypothesis that a cereal grain-based supplement, fed to cows that are in mid–late lactation and grazing low metabolisable energy and high neutral detergent fibre content paspalum (Paspalum dilatatum Poir.)-type pastures, will increase milk yield, but that this response will diminish with successive increments of supplement. A further objective of this research was to investigate some of the factors, such as altered rumen fermentation pattern, that might vary the point at which diminishing returns start to occur. Cows grazed irrigated perennial pasture at an allowance of either 25 (experiment 1) or 31 (experiment 3) kg of dry matter (DM) per cow per day in late summer–early autumn (mid–late lactation) and were supplemented with cereal grain-based concentrates up to 11 and 7 kg DM/cow.day in experiments 1 and 3, respectively. In experiment 1, there were 3 replicates of 6 treatments (3 cows in each treatment group) that involved the feeding of either 0, 3, 5, 7, 9 or 11 kg DM/cow.day of supplement for 50 days. Experiment 3 was conducted over 35 days. There were 2 replicates of 4 treatments (4 cows per treatment group) that involved the feeding of either 0, 3, 5 or 7 kg DM/cow.day of supplement. A further experiment (experiment 2), associated with experiment 1, examined the effects of offering cereal grain-based concentrates up to 7 kg DM/cow.day to dairy cows consuming 10 kg DM/day of herbage with a high paspalum content on aspects of rumen fermentation. Incremental responses of 40 g/kg fat-corrected milk (FCM) to increasing concentrate intake diminished with increasing concentrate intake, with the level of supplementation at which diminishing returns occurred dependent on herbage allowance and, therefore, herbage intake. At a supplement intake of 3 kg DM/cow.day, the response in FCM was 1.1 kg/kg concentrate DM in both grazing experiments. There were no further increases in milk production with additional increments of concentrates in experiment 3 where the pasture allowance was highest. In experiment 1, where concentrates were offered to a level of 11 kg DM/cow.day, and the pasture allowance was lower, diminishing returns were not as pronounced as in experiment 3 until the highest levels of concentrate intake. Substitution of supplement for herbage was a major factor in causing the diminishing returns in both experiments, but especially in experiment 3, where pasture intakes were higher. Milk fat content was significantly (P<0.05) reduced (41.8 v. 32.5 g/kg) when concentrate intake increased from 9 to 10.4 kg supplement DM/cow.day in experiment 1. It was hypothesised that this reduction in milk fat content was probably due to the effects of subclinical rumen lactic acidosis. This hypothesis was supported by the trend to lower rumen pH for longer periods as supplement intake increased as well as a more variable milk yield at the highest level of supplement intake. We conclude that responses of FCM of 1.1 kg/kg DM cereal grain-based concentrates can be achieved when they are fed twice daily up to 3 kg DM/day to dairy cows grazing restricted amounts of paspalum-type pasture in autumn. Beyond 3 kg DM/day, marginal responses diminished with increasing concentrate intake, with the level of supplementation at which diminishing returns occurred being dependent on herbage allowance and, therefore, intake.

Hay supplements to overcome underfeeding of dairy cows. 1. Early lactation

1981 ◽  
Vol 21 (109) ◽  
pp. 148 ◽  
Author(s):  
CR Stockdale ◽  
KR King ◽  
IF Patterson ◽  
DT Ryan
Keyword(s):  
Milk Production ◽  
Dry Matter ◽  
Nutritive Value ◽  
Early Lactation ◽  
Stocking Rate ◽  
Dry Matter Digestibility ◽  
The Cost ◽  
Economic Use

Seventy-seven cows of mixed breeds were allocated a range of pasture only or pasture/hay diets for the first 60 days of lactation. The variation in level of pasture intake was achieved by stripgrazing. The average in vitro dry matter digestibility and nitrogen content of the pasture offered was 72.0 and 3.11 % respectively, while those of the hay were 63.3 and 2.24%. The pasture alone treatments examined the effects of underfeeding on dairy cow productivity and the pasture/hay treatments established the extent to which these effects could be overcome by the use of hay as a supplement to limited pasture. After 60 days, all cows were grazed as one group at a stocking rate of 6.0 cows ha-1. Underfeeding in the first 60 days of lactation resulted in a loss of 68.3 kg milk/cow for each kg reduction in daily pasture intake, together with a decline in liveweight and body condition. When hay was offered as a supplement, it overcame the effects of underfeeding to a large extent although milk production still declined by 31.3 kg/cow for each kg reduction in daily pasture intake. There was a residual loss in milk production of 0.6 times the immediate loss for 60 days of underfeeding. The residual benefit gained from feeding hay at any level of underfeeding averaged 0.5 times the immediate benefit. Hay was unable to counteract completely the effects of underfeeding because its nutritive value for production was only half that of pasture, and the cows could not eat enough of it to overcome this. Some possible variations to these results are considered, taking into account the quality of the pasture and hay used. The economic use of hay as a supplement to limited pasture is discussed. Providing hay is used as a genuine supplement, the use of it will be economic as long as the cost of a kg of hay is less than the price paid for 0.049 kg butterfat. The limitations to this calculation are discussed.

Compensatory milk production within the bovine udder: effects of short-term non-milking of single quarters

1990 ◽  
Vol 57 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Jörn Hamann ◽  
Joachim Reichmuth
Keyword(s):  
Treatment Period ◽  
Milk Production ◽  
Early Lactation ◽  
Short Term ◽  
Pretreatment Period ◽  
The Mean ◽  
Compensatory Effect

SummaryDaily quarter-milk yields of eight high-yielding cows (24–28 kg/d) and eight heifers (14–24 kg/d) were measured to examine compensatory changes in milk production between quarters within an udder. Either one, two or three quarters per cow were left unmilked for 12 d, in early or late lactation, and then all quarters of all cows were milked normally for a further period of 12 d. Concentrate feeding levels were constant throughout the experiment.The mean daily yield per cow fell to 26, 59 and 75% during the period of milking either one, two or three quarters respectively. Twelve days after resumption of normal milking the total daily yield per cow was the same for cows continuously milked in two, three or all four quarters. Daily yield in cows with only one quarter milked continuously recovered to only 78% of the level of the pretreatment period.During the treatment period, the mean daily yield of the continuously milked quarters increased by almost 14% for cows milked in one quarter only, by more than 10% for two quarters milked, and by 4% per quarter if three quarters were milked. Milk yields of these quarters remained above their pretreatment levels when milking was resumed in the adjacent quarters.There was no difference in the compensatory effect between cows and heifers in early lactation, but the compensatory effects were lower in late lactation heifers.

Growth and carcass characteristics of prime lambs fed diets containing urea, lupins or canola meal as a crude protein source

2003 ◽  
Vol 43 (10) ◽  
pp. 1193 ◽  
Author(s):  
S. C. Wiese ◽  
C. L. White ◽  
D. G. Masters ◽  
J. T. B. Milton ◽  
R. H. Davidson
Keyword(s):  
Growth Rates ◽  
Crude Protein ◽  
Control Diet ◽  
Carcass Characteristics ◽  
Poor Performance ◽  
Canola Meal ◽  
Muscle Area ◽  
Eye Muscle ◽  
Cereal Grain ◽  
Alternative Sources

Lupin grain typically provides the main source of protein in most lamb finisher diets in Western Australia. The aim of this work was to determine whether alternative sources of nitrogen could provide a less expensive means of achieving the desired rate of liveweight gain and carcass characteristics. Fifty-one crossbred lambs were finished using 3 different sources of crude protein. These sources were either: (i) a control diet consisting of lupins, oats, barley and cereal chaff in which lupins provided 49% of the nitrogen (lupin diet); (ii) a diet consisting of a combination of cereal grain and urea (urea diet); or (iii) a diet in which lupins were partially replaced with expeller canola meal (canola diet). Diets were isonitrogenous (14.4% crude protein) and isoenergetic (10.5 MJ ME/kg DM). Lambs were gradually introduced to the diets over 2 weeks before being fed the diets ad�libitum for 5 weeks.Lambs fed the canola diet performed the best in terms of feed intake and liveweight gain while those fed the urea diet performed the worst. Respective growth rates for sheep fed the canola, lupin and urea diets were 272, 233 and 180 g/day, respectively, with significant (P<0.05) differences only between the canola and urea diets. Equivalent dry matter intakes for the 3 groups were 1660, 1570 and 1380 g/day respectively, with sheep fed the urea diets being significantly (P<0.05) lower than the other two. Acidosis was considered to be a major cause of the poor performance of sheep fed the urea diet, with 3 sheep from this treatment showing inappetance and markedly reduced growth rates ('shy feeders'). Lambs finished on all 3 diets produced acceptable carcasses. Carcass weights followed the trend of growth rates, but there were no significant differences between diets in carcass weight, dressing percentage, GR tissue depth, C�site fat depth, eye muscle area, muscle pH or meat colour. At the price of the feeds used in this trial, the canola meal diet was the cheapest feed per kilogram of liveweight gain despite being the most costly diet per tonne of feed.

Replacing wheat with canola meal in a partial mixed ration increases the milk production of cows grazing at a restricted pasture allowance in spring

2014 ◽  
Vol 54 (7) ◽  
pp. 869 ◽  
Author(s):  
M. J. Auldist ◽  
L. C. Marett ◽  
J. S. Greenwood ◽  
M. M. Wright ◽  
M. Hannah ◽  
...  
Keyword(s):  
Milk Production ◽  
Milk Fat ◽  
Ground Level ◽  
Canola Meal ◽  
Wheat Grain ◽  
Holstein Friesian ◽  
Increase Milk Production ◽  
Metabolisable Energy ◽  
Dietary Treatments ◽  
Supplement Intake

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.

Sign in / Sign up

Export Citation Format

Share Document