Agricultural Emissions and Dairy Production Excellence

A set of practice flashcards covering agricultural greenhouse gas emissions, methane mitigation, dairy nutrition, cattle welfare, meat yield, and dairy market dynamics based on lecture transcripts.

According to the lecture, what percentage has rainfall in the southwest of Western Australia reduced by since the 1970's?

$$"20\%"$$

How is 'emissions intensity' defined and measured?

The amount of emissions per unit of product, measured in $kg\,CO_2-e/kg\text{ product}$

What is the atmospheric lifespan of Methane ($CH_4$)?

$$"12\text{ years}"$$

What is the atmospheric lifespan of Nitrous oxide ($N_2O$)?

$$"114\text{ years}"$$

Why can no single lifetime be defined for Carbon dioxide ($CO_2$)?

Because of the different rates of uptake by different removal processes, it can remain in the atmosphere for $5$ to more than $10,000\text{ years}"$

What method is used to generate equivalence between different greenhouse gases over a 100-year timeframe?

Global Warming Potential ($GWP100$)

What is the $GWP100$ of Nitrous oxide ($N_2O$)?

$$"265"$$

What percentage of excess heat resulting from climate change is absorbed by the ocean?

$$"90\%""$$

What does the acronym LULUCF stand for in the context of emissions accounting?

Land use, land-use change and forestry

What percentage of Australia's total emissions is currently provided by the LULUCF net sink?

Approximately $"16\%"$

In emissions accounting, what are Scope 1 emissions?

Direct emissions from sources like livestock, manure, crop residue, fuel, and fertilizer application

In emissions accounting, what are Scope 2 emissions?

Emissions from purchased electricity from the grid

In emissions accounting, what are Scope 3 emissions?

Supply chain emissions occurring pre-farm gate (e.g., chemicals, feed) and post-farm gate (e.g., transport, packaging)

What is the current price for an Australian Carbon Credit Unit (ACCU)?

$$"\$36.60"$$

According to the global emissions summary, which food product has the highest emissions intensity?

Beef

What was the agricultural contribution to the Australian national greenhouse gas inventory in 2024?

$$"19\%"$$

Which source is responsible for $"72\%"$ of agricultural emissions in Australia?

Enteric fermentation

What are the three main greenhouse gases of concern in agricultural emissions?

Carbon dioxide ($CO_2$), Methane ($CH_4$), and Nitrous oxide ($N_2O$)

What is the 2030 target for emissions reduction under the Australian Climate Change Bill?

$"43\%"$ reduction

What is the aim of the Global Methane Pledge launched at COP26?

To reduce methane emissions by $"30\%"$ by $"2030"$

Where does enteric fermentation occur in ruminants?

In the rumen, which is the largest compartment of the four-chambered stomach

What is the estimated microbial population in the rumen microbiome?

$$10^6 - 10^{11}/ml$$

What percentage of gross energy intake in ruminants is typically lost as methane?

$2$ to $12\%"$

What is the methane emission factor for a mature ewe?

$$6 - 10\,kg/hd/yr$$

What formula is used to predict methane emissions based on intake?

$$\text{Methane (g/day)} = 20.7 \times kg\,DMI/day$$

What percentage of variation in ruminant emissions is explained by dry matter intake?

$$80-90\%"$$

What is the achievable annual rate of emissions reduction through direct genetic selection for lower emitting animals?

$$0.5\% - 1\%\text{ per year}$$

How does the use of nitrogen (nitrates) as a supplement reduce methane?

$NO_3$ (nitrate) binds with $H$ (hydrogen) to form $NH_4$ (ammonium) instead of hydrogen binding with carbon to form $CH_4$

What reduction in methane yield was observed in the MLA trial using Asparagopsis oil at $25\,mg/kg\,DM$?

$$"22\%"$$

What is the active anti-methanogenic compound found in the red macroalgae Asparagopsis?

Bromoform

What methane inhibitor has shown a $20-40\%\text{ (up to }>76\%)$ reduction and is approved in Australia for beef and dairy?

Bovaer (3-nitrooxypropanol or 3-NOP)

What is the primary source of Scope 1 emissions in the pig and poultry sectors?

Manure management

What is the average methane intensity of kangaroo meat?

$$3.6\,kg\,CO_2-e/kg\text{ product}$$

What percentage of national nitrous oxide emissions in Australia originate from the agricultural sector?

Greater than $"75\%"$

How much nitrogen intake do ruminants typically excrete in urine and dung?

$$75-90\%"$$

What is the achievable rate of soil carbon sequestration when converting cropland to pasture?

$$0.25 - 0.5\,t/ha/year$$

In soil carbon and organic matter, what percentage of Soil Organic Matter (SOM) is Soil Organic Carbon (SOC)?

$$"58\%"$$

What are the four components of the Physical/Mental animal welfare assessment framework?

Nutrition, Environment, Health, and Behavioral Interactions

Under Australian standards, when can a person tail dock cattle?

Only on veterinary advice and only to treat injury or disease

By what year does the Australian dairy industry aim to phase out routine tail docking and calving induction?

$$"2030"$$

What is the industry target for the incidence of milk fever in dairy cows?

$"1\%"$ ($<3\%$ threshold)

What is the estimated annual cost of poor udder health to Australian dairy producers?

$$"\$150\text{ million}"$$

What is the estimated cost of a single clinical case of mastitis?

$$"\$350 - \$400""$$

According to the lameness scoring chart, what characterizes a Score 2 (Lame) cow?

Shortened strides, uneven walking, lame leg identifiable, arched back when standing and walking

What is the target age for disbudding calves using thermal cautery?

Before $"6\text{ weeks}"$ of age

How many bobby calves are slaughtered per year in Australia?

Approximately $"400,000"$

What is the maximum time off feed (TOF) allowed for bobby calves in the Australian supply chain?

$$"30\text{ hours}"$$

What is the optimal lying time per day for a dairy cow?

$$"12\text{ hours}"$$

According to dairy culling reality, what percentage of the herd is typically replaced yearly?

$$35 - 40\%"$$

What is the primary driver of cost-effective dairy nutrition?

Metabolisable Energy ($ME$) supply

What percentage of a ruminant's energy economy is provided by Volatile Fatty Acids (VFAs)?

$$"70\%"$$

What is the key precursor VFA for milk fat production?

Acetate ($C2$)

What is the optimal rumen pH threshold to avoid Subacute Ruminal Acidosis (SARA)?

$$>5.8$$

At what pH level is a cow considered to have clinical acidosis?

$$<5.5$$

What is the target Body Condition Score (BCS) for a cow at calving on the Dairy Australia 1-8 scale?

$$"5"$$

How many liters of milk are lost over a lactation for every BCS point below target at calving?

$$"450\text{ liters}"$$

In early lactation, how much energy is yielded by $50\,kg$ of liveweight loss?

$$"1,250\,MJ"$$

What is the typical voluntary waiting period between calving and re-mating?

$$30 - 60\text{ days}$$

How is 'Lean Meat Yield \%' (LMY%) defined?

The proportion of the carcase that is muscle (consumers prefer meat, not bone or fat)

What technology is considered very accurate for predicting LMY% and is used as a calibrating standard?

Dual-Energy X-ray Absorptiometry ($DEXA$)

In meat value, what was the AUS price for lean meat if the 44% fat trim was priced at $42/kg?

$$"\$117/kg"$$

At the same carcase weight ($23\,kg$), what is the retail value difference between a Fat Score 2 ($50\%\text{ LMY}$) and a Fat Score 4 ($46\%\text{ LMY}$) lamb?

Approximately $"\$30"$ ($173$ vs $144$)

Where is the GR site located on a lamb carcase?

$110\,mm$ from the midline of the carcase along the 12th rib

What is the order of tissue development in a growing animal?

Bone maturing first, then Muscle, then Fat maturing last

Which fat depot is late maturing relative to live weight?

Subcutaneous fat

What does the sheep genetics acronym PWWT stand for and represent?

Post Weaning Weight; represents growth potential

What the sheep genetics acronym PEMD stands for?

Post Weaning Eye Muscle Depth

What is the heritability of Lean Meat Yield in sheep?

$$"0.39"$$

In the Terminal Meat Index 'Carcase Plus', what is the weighting for growth, muscle, and reducing fat?

$$65\%\text{ growth, }35\%\text{ muscle, }5\%\text{ reducing fatness}$$

What is the negative phenotypic correlation value between LMY and Intramuscular Fat (IMF)?

$$-0.35$$

How is the MSA score calculated as a single score?

$$\text{Tenderness (0.3)} + \text{Juiciness (0.1)} + \text{Flavour (0.3)} + \text{Overall Liking (0.3)}$$

What are the MSA score thresholds for a 3-star (Good Everyday) and 5-star (Premium) grade?

3-star = $48+$; 5-star = $80+$

How many consumers session tests are performed per week for MSA grading development?

$$"1,260"$$

What is the 'clipping' protocol used for consumer MSA scores?

Trim the top $2$ and bottom $2$ scores from $10$ consumer tests

What is the 'Tenderstretch' effect in the MSA model?

The effect of carcase hanging technique on meat tenderness

What percentage of Australian milk production is exported?

$"36\%"$ ($30\%$ based on state-split data)

What is the domestic market's share of Australian milk production?

Approximately $"70\%"$

Which Australian state accounts for $"75\%"$ of national dairy exports?

Victoria

What are Japan and China's roles in Australian dairy exports?

They are major export markets; China imports the most tons of milk powders and cheese

What is the Western Australian average milk production per cow?

Approximately $"6,700\,L/year"$

What is the average herd size in Western Australia compared to the Australian average?

WA average is $527\text{ cows}$; Australian average is $245\text{ cows}$

In the Bega milk quality standards, what is the 'Excellent' target for Aerobic Plate Count (APC)?

$$<10,000\,cfu/mL$$

What is the somatic cell count (SCC) 'Excellent' target limit?

$$<200,000\,cells/mL$$

What is the quality deduction for Grade 6 milk (SCC > 400,000)?

$$"30\%"$$

Why is there zero tolerance for antibiotics in milk?

Small amounts pose health risks and inhibit bacterial fermentation used in yogurt and cheese production

What temperature and duration are used for UHT (Ultra Heat Treated) milk?

$$140^{\circ}C\text{ for 2 seconds}$$

What is the biological aim for the dairy reproduction cycle?

One calf per cow each year ($365\text{ days}$)

How many days is the standard gestation period for a dairy cow?

$$"280\text{ days}"$$

What is the '100-day in-calf rate' target for top farmers?

$$"58\%"$$

In the bovine oestrous cycle, what is the 'AM/PM Rule'?

Cows seen in heat in the morning are inseminated in the evening; those seen in the evening are inseminated the following morning

At what point does 'Standing Heat' occur in the oestrus behavior sequence?

Average duration of $18\text{ hours}$ ($6-24\text{ hour range}$)

What hormone causes Corpus Luteum (CL) regression in the synchronisation of oestrus?

Prostaglandin ($PGF2\alpha$)

What is the duration of uterine involution post-partum?

$$30 - 45\text{ days}$$

Which dairy breed is the most popular in Australia, making up nearly $1.4$ million cows?

Holstein-Friesian

What characterizes the Jersey breed in terms of milk quality?

High creamy milk content, ideal for making butter

Which Australian breeding index blends production, type, and health traits based on economic values?

Balanced Performance Index ($BPI$)

Which index fast-tracks fertility and mastitis resistance?

Health Weighted Index ($HWI$)

How much of the increase in lactation milk yield since 1980 is attributable to non-genetic factors (nutrition/management)?

$$2000\,L\text{ of the }3000\,L\text{ total increase}$$

What are the 'Three Leaf Grazing' principles for ryegrass?

Rotation length should equal the time taken for ryegrass to regrow 3 leaves after grazing

What is the base formula for the Phenotype ($P$)?

$P = G + E$ (Genotype + Environment)