Murray C Hannah

Agriculture Victoria

Cereal grains that differ in the rate and extent of ruminal fermentation differ in heat increment and may be used to improve thermoregulation during heat stress. This experiment investigated the responses of dairy cows in late lactation to a heat challenge when offered wheat-grain or corn-grain. Eighteen lactating cows, 220 ± 94 (mean ± standard de...

Body condition scoring is a valuable tool used to assess the changes in subcutaneous tissue reserves of dairy cows throughout the lactation resulting from changes to management or nutritional interventions. A subjective visual method is typically used to assign a body condition score (BCS) to a cow following a standardized scale, but this method is...

The diet of dairy cows in Ireland traditionally changes abruptly from predominantly pasture silage before calving to grazed perennial ryegrass immediately after calving. This potentially leads to problems with adaptation of microbes in the rumen with consequences of reduced intake and ultimately lower milk production. This experiment aimed to deter...

To increase the dry matter and metabolisable energy intake of cows, dairy farmers often supplement pasture with concentrates and conserved fodder. Feeding large amounts of highly fermentable concentrates to cows can result in metabolic issues, such as ruminal acidosis, and thus safer but more efficient introduction strategies are desirable. We asse...

Supplementing the diet of lactating cows with ingredients that increase energy density, or reduce internal heat production, may reduce some of the negative impacts of hot weather on milk yield. Thirty-two dairy cows were assigned either: (1) basal diet only, (2) basal diet plus canola oil, (3) basal diet plus betaine, or (4) basal diet plus canola...

Feed is the largest variable cost for dairy farms in Australia, and dairy farmers are faced with the challenge of profitably feeding their cows in situations where there is significant variation in input costs and milk price. In theory, the addition of 5.2 MJ of metabolisable energy to a lactating cow’s diet should be capable of supporting an incre...

Despite the fact that the sulphur hexafluoride (SF6) tracer technique was developed over 25 years ago to measure methane production from grazing and non-housed animals, no studies have specifically investigated whether ambient wind speed, temperature, relative humidity and rainfall influence the accuracy of the method. The aim of this research was...

In pasture-based dairy systems, feeding a complex concentrate mix in the parlor during milking that contains cereal grains and protein supplements has been shown to have milk production advantages over feeding straight cereal grain. This experiment had the aim of testing whether further milk production advantages could be elicited by adjusting the...

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...

Addition of fats to the diets of ruminants has long been known to result in a reduction in enteric methane emissions. Tannins have also been used to reduce methane emissions but with mixed success. However, the effect of feeding fat in combination with tannin is unknown. Eight ruminally cannulated Holstein-Friesian cows were fed four diets in a dou...

Estimation of dry matter intake (DMI) using the n-alkane technique was evaluated in lactating dairy cows fed fresh herbage and a partial mixed ration (PMR). Four dietary treatments were investigated in a 2 × 2 factorial experiment using 16 Holstein-Friesian dairy cows. Dietary treatments were combinations of low and high amounts of fresh herbage (8...

Wheat is the most common concentrate fed to grazing dairy cows in Australia, but no studies have examined the effects of wheat proportion in a pasture-based diet on milk production and methane emissions. In this 47-d experiment, 32 Holstein dairy cows were offered 1 of 4 diets during d 1 to 36. Cows in each of the dietary treatment groups were indi...

The dry matter intake (DMI) of forage-fed cattle can be used to predict their methane emissions. However, many cattle are fed concentrate-rich diets that decrease their methane yield. A range of equations predicting methane yield exist, but most use information that is generally unavailable when animals are fed in groups or grazing. The aim of this...

Enteric methane emitted by ruminants is a nutritional inefficiency that contributes to global warming. Feeding substantial quantities of wheat grain to dairy cows has been reported to decrease enteric methane emissions compared with other feeds. Feeding methane mitigating agents such as nitrate, fat and 3-nitrooxypropanol (3-NOP) to ruminants have...

Diets that contain high proportions of either wheat or supplementary fat have been individually reported to reduce enteric methane production. The objective of this research was to determine the effect of dietary fat supplementation on methane emissions and milk yield from cows fed diets containing either corn or wheat grains. It was hypothesized t...

BACKGROUND Supplementation of ruminant diets with wheat and corn grains influences ruminal fermentation. In vitro fermentation is a methodology that can be used to screen feeds for their potential to produce enteric methane. However, there is evidence that the diet of the donor cows could impact the results of in vitro analysis. This research inves...

An improved ability to predict pasture dry matter (DM) yield response to applied phosphorus (P), potassium (K) and sulfur (S) is a crucial step in determining the production and economic benefits of fertiliser inputs and the environmental benefits associated with efficient nutrient use. The adoption and application of soil testing can make substant...

Context The Australian dairy industry is characterised by pasture-based feeding systems, where grazed pasture is commonly supplemented with cereal grain to increase milk production of dairy cows. Perennial ryegrass (PRG; Lolium perenne L.) is the most commonly used pasture species, with a wide range of cultivars available. However, the nutritive ch...

The n-alkane technique for estimating herbage dry matter intake (DMI) of dairy cows was investigated in this experiment. Eight Holstein-Friesian dairy cows were offered perennial ryegrass ad libitum that had been harvested at two different herbage masses and during two different seasons, in order to assess the effect of herbage mass and season on t...

In previous studies using Ankom GP vented in vitro systems (Ankom Technology, Macedon, NY), methane production was estimated from gas production (GP) and a single gas sample from the incubation vessel's headspace at the end of the incubation. An accurate method requires measurement of methane in the incubation vessel's headspace and in the gases ve...

The effects of different wheat adaptation strategies on ruminal fluid pH, dry matter intake (DMI) and energy-corrected milk (ECM) were measured in 28 late-lactation dairy cows. Cows were fed either perennial ryegrass (PRG) hay or alfalfa hay and had no previous wheat adaptation. Wheat was gradually substituted for forage in 3 even increments, over...

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 winte...

BACKGROUND There are several methods for estimating methane production (MP) from feedstuffs in vented in vitro systems. One method (A; ‘gold standard’) measures methane proportions in the incubation bottle's headspace (HS) and in the vented gas collected in gas bags. Four other methods (B, C, D and E) measure methane proportion in a single gas samp...

Short-term studies have shown that feeding dairy cows diets containing a high proportion (>40%) of wheat may result in reduced milk fat concentration and reduced CH4 emissions (g of CH4/cow per d), but no long-term studies have been done on these responses. This study compared the milk production and CH4 responses when 24 dairy cows were fed diets...

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 expe...

The effects of a major dietary change on ruminal fluid pH, volatile fatty acid (VFA), lactate and ammonia concentrations, dry matter intake (DMI) and milk yield were measured in 32 dairy cows in late lactation. All cows were initially fed 100% lucerne hay cubes and were then gradually introduced to a diet with wheat comprising 40% of total dry matt...

Almond hulls and citrus pulp have been fed to dairy cows with variable responses for milk production, but no information exists on their effect on enteric methane emissions. This experiment examined the effects of dietary supplementation with either almond hulls or ensiled citrus pulp on the milk yield, milk composition, and enteric methane emissio...

The locations dairy cows visit on grazing system farms can have important implications for nutrient management. Excreted nutrients can be directly returned to pasture paddocks, or returned to places where these nutrients can either be collected for reuse, or are not collectable and therefore lost. Previous research has shown that nutrient accumulat...

Wheat is the most common concentrate fed to dairy cows in Australia, but few studies have examined the effects of wheat feeding on enteric methane emissions, and no studies have compared the relative potencies of wheat, corn, and barley for their effects on enteric methane production. In this 35-d experiment, 32 Holstein dairy cows were offered 1 o...

There is a need to develop simple, accurate methods for predicting methane emissions, yields and intensities of dairy cows. Several studies have focussed on the relationship between the concentrations of trans-10 plus trans-11 C18:1 fatty acids in milk fat and methane yield. The aim of the present study was to perform a meta-analysis to quantify re...

Holstein–Friesian dairy cows managed in pasture-based systems are capable of lactating for considerably longer than the traditional 300 days. However, the partitioning of dietary nutrients in the second 300 days of an extended lactation has been shown to be different from that in the first 300 days. The partitioning of dietary nitrogen (N) was inve...

Grape marc consists of the skins, seeds and stems remaining after grapes have been pressed to make wine. Interest in grape marc for use as a dietary feed additive for ruminants has grown after recent research showed that inclusion of grape marc in the diet of dairy cows reduced their enteric methane (CH4) emissions. In the present research, in vitr...

An improved ability to predict pasture dry matter (DM) yield response to applied nitrogen (N) is a crucial step in determining the production and economic benefits of N fertiliser inputs with associated environmental benefits from reducing inefficient N fertiliser use. Pasture DM yield responses to applied N fertiliser from 920 independent field tr...

Large N surpluses are a feature of most dairy farms worldwide. Despite the predominance of grazing systems in Australia, increasing animal densities and greater reliance on purchased feed mean that feed nutrient inputs and the role of grazing animals in N flows and deposited loads have grown. However, quantifying nutrient intakes and N excretion is...

The increasing use of nitrogen (N) fertiliser in pasture-based dairy systems is commensurate with a decline in N use efficiency and increase in N surplus. An improved ability to predict pasture yield response to applied N is a crucial first step in determining the production and economic benefits of N fertiliser inputs. Data and meta data on pastur...

A positive association between milk protein concentration (MPC) and reproductive performance in dairy cows has been shown in several studies globally. This association may positively influence farm productivity and profitability, particularly in seasonally calving, pasture-based herds. However, the differences in milk production and energy allocati...

In vitro methane production from three experiments incubating 1.0 gm DM of wheat and Lucerne, different amounts (0, 0.5, 1.0 and 1.5 gm DM) of wheat and lucerne and Lucerne, corn, wheat and barley with different degrees of processing, was calculated using [CH4 concentration in headspace x headspace volume] + [CH4 concentration in gas bag x GP] as t...

Variation in feeding behavior and milk production of grazing dairy cows fed a mixed ration was measured. Experiments were conducted in spring (early lactation) and autumn (late lactation) with 48 Holstein-Friesian dairy cows. Pasture allowance (low vs. high) and amounts of supplement (low vs. high) were applied to determine the effect on variation...

Effects of different strategies for feeding supplements to grazing dairy cows on the composition and coagulation properties of milk and the subsequent yield and quality of Cheddar cheese were measured. The experiment used milk from 72 Holstein-Friesian cows, averaging 45 d in milk, fed according to 1 of 3 feeding strategies: (1) cows grazed a restr...

The methods for estimating methane emissions from cattle as used in the Australian national inventory are based on older data that have now been superseded by a large amount of more recent data. Recent data suggested that the current inventory emissions estimates can be improved. To address this issue, a total of 1034 individual animal records of d...

Forage brassica and chicory crops provide an alternative to perennial grass pastures as a forage supply for grazing dairy cows during summer, but there is little information about their effects on milk production and methane (CH4) emissions. Thirty-two Holstein–Friesian cows were fed for 10 days on a diet of lucerne cubes (750 g/kgDM)and grain (250...

A widely used method for the in vitro measurement of fermentation parameters, total gas and methane (CH 4) production (mL/g) from feed samples employs Ankom RF Technology with vented bottles, initially flushed with carbon dioxide (CO 2). The volumes of gas accumulated between ventings, and the volumes vented, are calculated from the headspace press...

The feeding of cereal-based supplements is common in the Australian dairy industry, as it allows cows to increase intakes of total dry matter (DM) and metabolisable energy (ME), while achieving greater stocking rates, greater pasture utilisation and greater milk production per hectare than occurs when cows are fed pasture-only diets. However, for t...

Feed types consumed by cows on 44 contrasting dairy farms from all major dairy regions in Australia were identified and sampled on five occasions over a 15-month period to determine nutritive characteristics and mineral concentrations. Perennial ryegrass was the most dominant and commonly used forage, although a broad range of other home-grown fora...

Milk production responses of grazing cows offered supplements in different ways were measured. Holstein-Friesian cows, averaging 45 d in milk, were allocated into 8 groups of 24, with 2 groups randomly assigned to each of 4 feeding strategies. These were control: cows grazed a restricted allowance of perennial ryegrass pasture supplemented with mil...

This review examines research aimed at reducing enteric methane emissions from the Australian dairy industry. Calorimeter measurements of 220 forage-fed cows indicate an average methane yield of 21.1 g methane (CH4)/kg dry matter intake. Adoption of this empirical methane yield, rather than the equation currently used in the Australian greenhouse g...

Soil chemical properties are likely to be unevenly distributed within grazed dairy farms. Paddocks that dairy cows graze more frequently, or parts of paddocks that they regularly visit potentially have elevated nutrient levels due to the excreta returned by the herd. We measured the between and within paddock distribution of a range of agronomic so...

Nutrient exports from agriculture are an important environmental issue in many countries. In some production systems phosphorus (P) and nitrogen (N) accumulate at or near the soil surface and cultivation is one option for addressing the legacies of previous nutrient applications. This study aimed to compare the effects of cultivation (mouldboard pl...

The sulphur hexafluoride (SF6) technique used to estimate methane emissions from ruminants involves placement of a permeation tube into the reticulo-rumen of animals. The permeation tube releases a trace amount of SF6 across a polytetrafluoroethylene membrane. The animals emit in exhaled breath enteric methane along with a trace amount of the SF6 g...

Efficient nutrient management is a critical component of profitable and sustainable milk production on modern dairy farms. While manufactured fertilisers can be a large part of dairy farm operating costs, the net flux of nutrients onto farms in feed and fertiliser can be large, with increasing scrutiny of off-farm nutrient impacts. In this study, w...

Dairy products are the single largest commodity exported from south east Australia. However, dairy farming contributes 12% of Australia's national greenhouse gas emissions. During the last nine years, the Australian Federal Government and the Victorian State Government have funded considerable research towards mitigating greenhouse gas emissions fr...

The sulphur hexafluoride (SF6) tracer technique enables determination of enteric methane emissions from large numbers of individual ruminant animals. The objective of this research was to identify and correct substantial errors within the SF6 technique. Six experiments were undertaken using respiration chamber, laboratory or SF6 techniques. Experim...

Methane (CH4) emissions from dairy cows are technically difficult and expensive to measure. Recently, some researchers have found correlations between the concentrations of specific fatty acids in milk fat and the CH 4 emissions from cows that could obviate the need for direct measurement. In this research, data on individual cow CH 4 emissions and...

Late-lactation Holstein cows (n = 144) that were offered 15 kg dry matter (DM)/cow per day of perennial ryegrass to graze were randomized into 24 groups of 6. Each group contained a fistulated cow and groups were allocated to 1 of 3 feeding strategies: (1) control (10 groups): cows were fed crushed wheat grain twice daily in the milking parlor and...

Grape marc (the skins, seeds, stalk, and stems remaining after grapes have been pressed to make wine) is currently a by-product used as a feed supplement by the dairy and beef industries. Grape marc contains condensed tannins and has high concentrations of crude fat; both these substances can reduce enteric methane (CH4) production when fed to rumi...

Predictable release of sulphur hexafluoride (SF6) tracer gas from permeation tubes into the reticulo-rumen is necessary to estimate methane emissions from ruminants using the SF6 tracer technique. Any discrepancy between the laboratory determined rate of SF6 release from permeation tubes and the actual rate of release in the reticulo-rumen would bi...

The objective of this experiment was to evaluate how feeding space allowance and provision of feed barriers interact to affect feeding and social behavior of dairy cows fed a partial mixed ration on a feed-pad. The treatments were factorial with 3 feeding space allowances (0.6, 0.75, or 1.0 m of trough space per cow) and feed troughs that were eith...

This experiment was conducted to determine the effects of diets supplemented with cottonseed oil, Acacia mearnsii-condensed tannin extract, and a combination of both on composition of bovine milk. Treatment diets included addition of cottonseed oil (800 g/d; CSO), condensed tannin from Acacia mearnsii (400 g/d; TAN) or a combination of cottonseed o...

This experiment measured milk production responses of grazing cows offered supplements in different ways. Holstein-Friesian cows averaging 89 days in milk, were allocated into six groups of 36 (each group including three rumen-fistulated cows). Two groups were randomly assigned to each of three dietary treatments: (1) cows were offered milled barle...

The objective of this experiment was to compare ruminal pH and whole-tract digestibility in cows consuming fresh cut herbage plus concentrates and silage or hay fed either separately or as a partial mixed ration (PMR). Fourteen rumen-fistulated Holstein-Friesian cows that had calved in late winter were housed in metabolism stalls for 9-day experime...

Vegetable farms are one of many nitrogen (N) sources adversely affecting Lake Taihu in eastern China. Given the lack of quantitative “cause and effect” relationships and data relating to these systems, we developed a conceptual Bayesian network to investigate and demonstrate causal relationships and the effects of different mitigation strategies on...

The SF6 tracer technique which is used to estimate enteric methane emissions from ruminants requires knowledge of, or at least accurate prediction of, the rate of release of SF6 from permeation tubes (Williams et al. 2011). The rate of release of SF6 from permeation tubes is generally determined by placing them in an incubator set at 39ºC and the w...

It has been proposed that methane emissions from dairy cows could be predicted from the concentrations of specific milk fatty acids (Chilliard et al. 2009). The proposed relationships were developed from a corn silage and concentrate diet with an addition of one of whole linseed, extruded linseed or linseed oil. The relationships have been tested b...

Perennial ryegrass (Lolium perenne) is a major pasture species grazed by cattle and sheep in the temperate regions of Australia. The principal aim our study was to examine effects of ryegrass endophytic fungi on in vitro ruminal methanogenesis. Samples of perennial ryegrass pasture infected with either wild-type endophyte or the novel endophytes, A...

This study examined effects on milk yield and composition, milk fatty acid concentrations and methane (CH4) emissions when dairy cows were offered diets containing different amounts of algal meal. The algal meal contained 20% docosahexaenoic acid (DHA) and cows were offered either 0, 125, 250, or 375 g/cow per d of algal meal corresponding to 0, 25...

Agriculture, particularly pastoral based dairying, has intensified significantly in the past two decades. There are mounting concerns that this intensification could be linked to declining environmental quality. This paper analyses changes in water quality in three catchments in south-west Victoria, Australia, where the dominant land use has been d...

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),...

Milk production responses of grazing cows offered supplements in different ways were measured. Holstein-Friesian cows, averaging 227 d in milk, were allocated into 6 groups of 36, with 2 groups randomly assigned to each of 3 feeding strategies: (1) cows grazed perennial ryegrass pasture supplemented with milled barley grain fed in the milking parlo...

Dairy farm management practices associated with animal treading can have detrimental impacts on physical and hydrological properties of soils. The objectives of this study were to: (i) quantify the variability in soil physical properties; and (ii) develop a sampling strategy for future monitoring of Victorian dairy soils. Soil physical data were co...

An experiment was conducted to quantify the changes in energy partitioning resulting from grain supplementation in herbage-fed dairy cows at 4 stages during a 670-d lactation. The experiment used 16 lactating Holstein-Friesian cows, with a control and a grain treatment being randomly allocated to 8 cows each. During 4 measurement periods (each of 4...