MCQ1 Flashcards
(231 cards)
1
Q
What is the total land area in Ireland?
A
6.9 million hectares
2
Q
What amount of land in Ireland is used for agricultural purposes?
A
4.5 million hectares
3
Q
What amount of land in Ireland is used for forestry?
A
0.73 million hectares
4
Q
What percentage of agricultural area is devoted to pasture, have and grass silage?
A
81% (3.63 million ha)
5
Q
What percentage of land is devoted to rough grazing?
A
11% (0.47 million ha)
6
Q
What percentage of land is devoted to crops, fruit and horticulture production?
A
8% (0.38 million ha)
7
Q
What percentage does the agri-food sector account for in employment?
A
Almost 10%
8
Q
What percentage of employment in the agri food sector is provided outside of Dublin and in the mid-east region?
A
Between 10-14%
9
Q
What was the average FFI across all systems in 2023?
A
19,925
(45% decrease on 2022)
10
Q
What is the value of the total agri-food exports in 2023?
A
18.28 billion euros
11
Q
What is the value of the total dairy exports in 2023?
A
6.3 billion
12
Q
What is the value of the total meat and livestock exports in 2023?
A
4.2 billion
13
Q
What is the value of the total prepared consumer foods exports in 2023?
A
3.1 billion
14
Q
Where are most people employed in the agri-sector in Ireland?
A
The border
15
Q
What is the total number of farms in Ireland?
A
135,037
16
Q
What is the avergae farm size in Ireland?
A
33.4 ha
17
Q
What percentage of farm holders were over the age of 65 in 2016?
A
Around 25%
18
Q
What percentage of farm holders are under the age of 35?
A
5%
19
Q
In 2018, what percentage of workers in agriculture, forestry and the fishing sector were female?
A
16.4%
20
Q
Where are the most cows in Ireland?
A
Cork- 25%
Tipperary- 11.5%
Limerick- 8%
21
Q
Where is there the least number of cows in Ireland?
A
Leitrim- 2,421
Dublin- 2,760
22
Q
Where are 60% of the beef farms located?
A
Border, midland and western regions of Ireland
23
Q
What is the average farm size for a suckler farmer?
A
27.5 ha
18 cows
24
Q
What were the Irish dairy exports values at in 2023?
A
6.3 billion euros
25
How much did the global milk supply grow by in 2023?
1%
26
What amount of exports were cheese?
1.3 billion euros
27
What amount of exports were powder milk?
825 million euros
28
What amount of exports were specilised nutritional powders?
800 million euros
29
What amount of exports were butter?
1.3 billion euros
30
What was the average FFI for a dairy farm 2023?
24,432
31
What is Food Harvest 2020?
The governments target is to grow food exports to 12 billion euros by 2020
- Increase output by 33%
- Increase milk production by 50% (have exceeded)
32
What is Food Wise 2025?
- Increase the value of agri food exports by 85% to 19 billion euros
- Increase the value added to the sector by 70% to 13 billion euros
- Increase the value of primary production by 65% to 10 billion euros
- Extra 23,000 jobs in the agri food sector by 2025
33
Food Vision 2030
- A sustainable food system is profitable throughout (economic sustainabilty), has broad based benefits for society (social sustainability) and has a positive or neutral impact on the natural environment (environmental sustainability)
1. A climate start, environmentally sustainable food sector
2. Viable and resilient primary producers with enhanced wellbeing
3. Food which is safe, nutritous and appealing: trusted and valued at home and abroad
4. An innovative, competitive and resilient agri-food sectore, driven by technology and talent
34
Farm to fork strategy
- The European Green Deal sets out how to make Europe the first climate-neutral continent by 2050
- It addresses comprehensively the challenges of sustainable food systems and recognises the inextricable links between healthy people, healthy societies and a healthy planet
- Reduce dependency on pesticides and anatimircrobials, reduce excess fertilisation
- Increase organic farming, improve animal welfare, and reserve biodivesity loss
35
What are the challeneges for agriculture?
- Environment (Climate change and GHG emissions, ammonia emissions/air quality, Nitrated/water quality/nitrated directive)
- Sustainability
- Profitability
- Labour
- Biodiversity
- Land availability/cost/fragmentation
- Brexit
- Mercosur Trade Deal
- CAP Reform
- Market access and competitive advantage
- Image/animal welfare/consumer perception
- Adaption of new technologies
36
What percentage was agriculture responsible for of the GHG emissions in Ireland in 2023?
- 37.8%
- Emissions from agriculture decreased by 4.6% in 2023
37
Where do agricultural emissions come from?
- Methane gas belched out by cows
- Methane and nitrous oxide gas from slurry
- Nitrous oxide from urine patches and N fertiliser
38
People in Dairy Action Plan
Dairy sector needs to attract 6,000 people (future farmers and employees) by 2025
39
What does viable farming mean?
A farm is defined as economically viable if the farm income can remunerate family labour at the minimum agricultural wage, and provide 5% return on the capital invested in nonland assets
40
What does farm sustainability mean?
If the farm business is not viable, the household is still considered sustainable if the farmer or spouse has a off-farm income
41
What does vulnerable mean?
A farm is considered to be economically vulnerable if the farm business is not viable and if neither the farmer nor spouse works off the farm
42
What percentage of the population will live in urban areas by 2050?
- 70%
- Almost 75% will be in Asia and Africa
43
What percentage of the worlds population are living in counties that are recording strong economic growth per annum?
40%
44
What is the number of middle class in China and India forcasted to increase by over the next 20 years?
1.2 billion
45
What percentage increase in income equates to a 5% increase in beef consumption?
10%
46
What phase is the global beef supply in?
The tightening phase
47
What is Irelands GHG footprint in cow milk production?
1 kg CO2 eq/kg FPCM
48
What is Irelands water stress index?
0
49
How many dairy cows are in Ireland?
1.646 million
50
What is the average herd size in Ireland?
91
51
What is the average dairy farm size?
55 ha
52
How many dairy farms are in Ireland?
around 17,000
53
On average, how many days of the year are cows out on pasture?
240 days
54
What percentage of the cows diet is grass?
95%
55
What is the carbon footprint of dairy farms in Ireland?
0.97 kg CO2e per kg FPCM
56
What happened when the quotas were introduced in 1984?
- Total milk production has to level off
- Average yield per cow increased
- Number of cows in Ireland has to fall
57
What happened to the quotas when they were abolished in 2015?
- Total milk production began to increase again
- Average yield per cow levelled off
- Number of cows in Ireland has increased (400-450,000)
58
What does a greater amount of forage in the diet lead to?
Lower yield of milk
59
2022 Milk Output in Ireland Figures
- 502 million litres was consumed as liquid milk
- 268,700 tonnes of butter
- 173,700 tonnes of skim milk powder
- 287,000 tonnes of cheese
60
Dairy breeds in Ireland
- Dairy Shorthorn in 1960's
- British Friesian
- Holstein
- Crossbreeding (HF X Je)
61
Milk Price Equation
A+B-C
A= value per kg of fat
B= value per kg of protein
C= carrier and processing costs per kg which will be a negative value
62
How many cows were in the EU in 2023?
19.7 million dairy cows
1.7% less than 2022
63
Who had the largest dairy cow population within the EU?
Germany- 3.7 million dairy cows
18.8% of the total EU dairy cow population
64
Where was the smallest number of dairy cows recorded in the EU?
Malta
5,930 dairy cows
65
What country had the largest decline in dairy cows in 2023?
Germany
Loss of 2.5%
66
What country had the largest expansion within the EU for dairy production?
Poland
Up 1.5%
67
How many dairy producers in the UK?
7,500
68
How many milking cows in the UK?
1.63 million
69
How many litres per year of milk in UK?
12.4 billion
70
Average dairy herd size in the UK
160
71
Where does the UK rank in the world as producers?
10th largest producers in the world
72
How many dairy cows globally?
270 million
73
EU 27 Self sufficiency percentage?
117.34%
74
Characteristics of the US Dairy Production
- bST
- High costs of production
- Scale of operation
- Cows mainly indoors
75
What is the total effective hectares of dairy land in New Zealand?
1.73 million hectares
76
What percentage of the worlds milk does NZ produce ?
3%
77
Where does NZ rank in the world producers?
7th largest in the world
78
How many dairy employees in NZ?
46,000
79
Who has the worlds highest level of dairy self-sufficiency?
New Zealand
80
What percentage of the New Zealand dairy sales represent of the world trade in dairy products?
40%
81
What percentage of NZ's dairy production is exported?
- 95%
- 140+ markets
- Mainly China, Australia, US, UAE and Japan
82
What is the cost of NZ's annual exports?
- 19 billion NZ dollars
- Biggest export earner
83
What were the top five dairy export products from NZ?
- Whole milk powder
- Butter
- Cheese
- Infant formula
- Skim milk powder
84
How much milk does NZ produce per year?
20.7 billion litres
85
How many dairy cows in NZ?
4.67 million cows
86
How many dairy herds in NZ?
10,601 herds
87
What is the average dairy herd size in NZ?
441
88
Similarities between NZ and Ireland
- Temperate climate
- Grass focused system
- Export focused industry
- Low input low output system
89
When is Spring in NZ?
September to November
90
When is winter in NZ?
June to August
91
When is Summer in NZ?
December to February
92
When is Autumn in NZ?
March to May
93
What is the main breed in NZ?
- Holstein Friesian/ Jersey crossbreed
- Holstein Friesian
- Jersey
- Ayrshire
94
What types of production systems are there?
- Spring calving systems
- Autumn calving systems
95
What percentage of herd in Ireland are spring calving?
90%+
96
A cows year
- Calving
- Early lactation (100 days)
- Mid lactation (100 days)
- Late lactation (100 days)
- Dry period (65 days)
97
When do cows need a high energy status?
Up to at least 130 days post calving
(conception management)
98
When is the transition period?
14- 21 days pre and post calving
99
When is peak grass growth and peak milk production?
May
100
What percentage of total milk production is from grazed grass?
90%
101
Total costs of production vs proportion of grass in the cows diet?
A 10% increase in grazed grass in the feeding system, the cost of milk produced will be reduced by 2.5 c/l
102
How do we maximise milk production from grass?
Calve cows as close as possible to the grass growing season
103
What is the range of CP in grass?
16-28% kg DM
104
What is the range of UFL in grass?
0.85-1.05 kg DM
105
When does calving start and how long does it go on for?
- Jan/Feb
- 12 weeks
106
When should the majority of cows calve?
The first 6 weeks
107
When are most of the calves born?
Between January and April
108
How long are calves milk reared?
8+ weeks and then weaned
109
How long should the dry period be before the cows calve down again?
8 weeks
110
When does breeding start?
Around 1st of May for 1st February calving
111
What is a cows gestation length?
280 days
112
How long is the breeding season?
- 12 weeks
- Cows not in calf after this are culled
113
When is there a deficit of grass?
- September to March
- Feed with concentrates or forage supplementation
114
When is there grass quality issues?
- At peak in May
- Grassland management is important here
115
When is the cows peak yield?
6-8 weeks post calving
116
How to calculate lactation yield?
Peak yield x 220
117
What is the average yield of a cow calving in mid February?
5,000kg
118
How long is the window to get a cow back in calf after calving?
80-83 days
119
How long is the voluntary waiting period/
42 days
120
How many days to get the cow in calf?
41 days
121
How long is the cows oestrous cycle?
21 days
122
When to inseminate?
80 days post calving
123
When is implantation?
100-130 days
124
For compact calving, what should the 3 week submission rate be?
90%
125
Conception rate at 1st service?
>60%
126
What is the target calving interval?
365 days
127
What percentage should culling for fertility be?
<10%
128
Cost of infertility when there is 1 months slippage in Cl?
>200 euros/cow
129
What is the cost of infertility when there is a 10% higher than planned empty rate?
100 euros/cow
130
In 2021/2022, how many registered liquid milk producers were there for winter milk systems?
- 1,286
- 8% of the national production
131
How many non-registered winter milk producers supplied milk were there?
600-800
132
Spring vs Autumn milk?
Low cost of grass vs high cost of silage and concentrates
133
When do Autumn cows calf?
September to December
134
What are the additional costs of autumn and winter milk production?
- Cows calve during the autumn and winter are producing their peak milk yields at the end of the grazing season, off grass silage and concentrates which therefore has a lower potential production than spring grass
- Additional concentrate supplements need to be fed to cows calving in the autumn and winter compared to cows calving in the spring
135
Why is the overall reproductive performance of the herd when confined to a compact 12 week breeding season often poor?
- Short day length in winter
- Crowded housing conditions and slippery foot conditions on slats resulting in restricted oestrus activity among the housed cows
- Reduced oestrus detection when based on tail paint and observation
136
Autumn calving cows diet
- Silage and concentrates fed indoors over the winter period (3-6 months)
- Benefits of extending the grazing season in the Autumn
- Grazed grass is superior in feeding value compared with grass silage in terms of milk production and protein content
137
Characteristics of a low input dairy system?
- Matching stocking rate to grass growth rates
- Max utilisation of least cost feed
- Competitive resilience
- May be suboptimal in periods of higher milk prices
- Farm expansion reliant on high animal numbers
138
Characteristics of high input dairy systems?
- TMR
- Confinement
- High output
- Scalable
- Reliance on purchased feed
- Risky (ability to cope with volatility?)
- Complexity
- Cost control issues
139
Characteristics of middle ground system in between low/high input systems?
- High solids per cow and per ha
- Maintain grass focus
- Moderate use of purchased feed
- Fertility and output goals
140
e-Profit Monitor
- Physical performance measures
- Financials: variable and fixed costs
- Compare spring vs winter (milk output, number of farms, drives of cost/profit between the two systems)
141
Measures of profitability?
- Net margin/cow
- Net margin/litre
- Net margin/ha
142
Benefits of multispecies swards for ruminant production?
- Need to reduce N losses from farm
- Most efficient method= reducing N inputs
- Nitrogen fertiliser and concentrate feed
- Can we reduce the level of N applied to swards, while maintaining biomass and milk production?
143
Forage production from multispecies swards
- Multispecies outperformed PRG only treatments at both low (90kg N/ha) and high (250 kg N/ha) rates of N
- Multispecies receiving 120 kg N/ha per year matched the annual yield achieved by PRG receiving 360 kg N/ha per year (12 T DM/ha)
144
Key benefits of Plantain Potency and Practice (PPP)
1. Reduced fertiliser requirement
-Legumes: essential component for N
fixation
2. Nutrient use efficiency- Microbial protein
- Animal performance = milk production,
ADG
3. Soil health and biodiversity
145
What are multispecies forages?
Multispecies foragers are forages that contain 2 or more plant species from at least two functional groups
146
What are the three primary functional groups for multispecies?
- Grasses
- Legumes
- Herbs
147
Multispecies functional group- Grass
- Nutritious and palatable
- Shallow, fibrous roots and vigrous growth, easy to manage
- Ability to persist under adverse conditions and sub-optimal soils
- High energy- 10-11 ME
- Sensitive to drought/moisture deficits
- N dependent (Modern varieties have a high requirement- 200 kg N+)
148
PRG characteristics
- Grazing and silage
- Very persistent
- 5+ years
- Flexible and tolerant of grazing
- High intakes
- Sensitive to climate
- Drought
149
Timothy grass characteristics
- Grazing and silage
- Very persistent
- Drought and frost tolerant
- Better on heavy ground
- 1st year slow to establish
150
IRG characteristics
- Silage (2-year ley)
- High production (up to 18T)
- Highly digestible (Reduced after 1st cut)
151
Westerwold Ryegrass
- Silage (annual ley)
- High production (up to 18T)
- Highly digestiBle (68-75 DMD)
152
Characteristics of legumes
- Fix high amounts of N (100-200+ kg N/ha annually)
- Highly degradable and nutrient rich (milk solids and ADG)
- Energy rich (RC-10 ME, WC- 11 ME)
- Can be slow to establish (sensitive to low temps, high moisture)
- Needs to be sown with perennial forages (Spring growth, reduce risk of bloat, persistency)
153
Why include legumes?
- Essential to support forage growth and biodiversity (earthworms and bees love WC)
- Residual N for subsequent crops
- Common legumes such as white clover, red clover, vetch (annual)
154
IRG and RC
- Good persistence (3+ years)
- Rapid growth
- Drought resistant, can oversow into grazing swards
- Avoid tight grazing, crown 6cm above ground
- Cut silage higher
155
PRG and WC
- Helps ground cover with upright PRG
- Medium leaf best for grazing
- Persistent- 4+ years
- Also suited to timothy but not on heavy soils
- Under sow with trefoil in crops etc
156
Westervold and Vetch
- Very vigorous growth
- Soil improver
- Annual green crop/cover crop
- Forest tolerant
- Can sow late into Autumn and harvest in Spring
157
Characteristics of herbs
- Chicory, plantain, yarrow, sheeps parsley, salad burnet etc
- Mineral rich, tend to have deep rooting systems
- Highly degradable plants- high energy, low structural fibre and low DM
- High protein plants: 18-20%
- Can be sown in grazing ley mixtures or finishing mixes for dry stock (chicory, plantain and white clover for finishing lambs)
- Small seed size so adjust seeder and management accordingly
- Small seeds have less starch, so therefore they need more time to establish roots, leaves etc
158
Chicory herb
- Mineral rich
- Long taproot
- Soil improver
- Persistent when well managed (3+ years)
- Frost and drought tolerant
- Weeds common when sown but removed once grazed/cut
- Avoid over grazing (5-6cm+)
- Grazed at 7 leaf stage
- 10-11 ME
159
Plantain herb
- Mineral rich
- Long taproot
- Soil improver
- Similar persistency to well managed ryegrass
- Avoid trampling
- Frost and drought tolerant
- Deep roots good for light soils
- Graze at 6 leaf stage
- 11-12 ME
160
Why is fibre important for animals?
Key energy source
161
What do bacteria in the rumen digest?
- Carbs to VFA's
1. Acetate- increases in forage diets
2. Propionate- increases in starch diets
3. Butyrate- formed from acetate
162
Rate of VFA production
- Feedstuff- i.e maize vs grass silage
- Rumen pH- low pH reduces fibre digestion (6-6.2)
- Forage degradability (rapidly or slowly degradable can influence pH, rumen passage rate etc)
163
What is the challenge for rumen fermentation?
To provide forage which balances rapidly and slowly degradable carbohydrates to maintain rumen function and production
164
What are the two forms that protein is available in?
- Rumen degradable protein (RDP)
- Rumen undegradable protein (RUP)
165
What protein is degraded largely to ammonia?
- RDP
- Energy + ammonia = Microbial protein
166
What is the true protein?
- Microbial protein
- Carbohydrate availability
- Forage degradability
167
What is invasive with animals, time consuming and costly?
Degradability
168
What are the other measures that can indicate digestibility?
- NDF and ADF fibre density measures
- DMD = 88.99 - [0.779 x %ADF (on a dry matter basis)]
169
What are common feedstuffs?
- Straw:
85% NDF, 55% ADF, 6-6.5 ME
- Maize meal:
10% NDF, 3% ADF, 13.5 ME
- Soya Hulls:
60% NDF, 50% ADF, 11.5 ME
170
What is nutrient availability influenced by?
Degradability
171
Is it difficult to manipulate nutrient supply in forage based diets?
- Yes
- Dependent on the plant composition of the forage
- Including alternative species may help improve nutrient supply and animal performance
172
Compared to a PRG sward, lambs suckling ewes which grazed a 6 species sward had higher or lower liveweight at weaning?
- Higher
- 2.4kg
- Reached slaughter 2 weeks earlier
173
PRG vs MSS for steers
- Turned out and housed >40kg heavier
174
Microbial protein equation
Energy + ammonia = microbial protein
175
Rapidly degradable fibre
- PRG: high in sugar (WSC)
- Herb species: high in pectin
176
Improved nutrient use efficiency
- Reduces ammonia loss as urea in urine: up to 50%
- Increased milk production and ADG
177
What is the challenge of the rapidly degradable nature of herb and clover species?
It can impact milk fat production
178
Establishment of MSS under grazing
- Weed management the year previous if possible
- Plant mid April to let July
179
Timeline for establishing a MSS?
- Spray (4L/acre)
- Graze
- Plough/disc
- Power harrow
- Spray (2L/acre)
- Fertiliser/disc/sow/roll
- Graze
180
What are the common weeds in a MSS?
- Chickweed
- Shepherds purse
- Lambsquarters
- Field pennycress
- Common fumitory
- Lady's thumb
- Wall rue
- Dead nettle
- Lad's Bedstraw
181
Grazing management for a MSS?
- Graze approximately 8 weeks post sowing
- Chicory 7 fully grown leaves
- Plantain 6 fully grown leaves
182
How did multispecies forage effect dairy cows mid and late lactation?
- Consistently increased the DMI and milk yield
183
How is the milk fatty acid and profile in milk from late lactation cows benefited?
By including clover and her species in grazing forages
184
What does multispecies swards do for urinary nitrogen concentration?
- It reduces it
- Helps reduce N loss via leaching (plantain)
185
Benefits of a MSS?
- High nutritive value
- Increased animal performance
- High summer growth rates
- Increased drought tolerance
- Reduced chemical N
- Various levels of root depths
- Increased biodiveristy
- Reduced anthelminitc usage (sheep)
186
Disadvantages of MSS?
- Poor autumn/early spring growth
- Weed control
- Increased rotation length
- Persistency
- Milk fat concentration
- PRGWC swards- bloat risk
187
The digestive tract features
1. Mouth
2. Oesophagus
3. Rumen
4. Reticulum
5. Omasum
6. Abomasum
7. Small intestine
8. Large intestine
188
How much digesting material does the rumen hold?
100- 120kg
189
What side of the cow is the rumen located?
Left hand side
190
What is the rumen made up of?
- Strong muscular pillars that partially divide it into several sacs
- Tongue-like projections called papillae- underlain by an extensive capillary system
191
What is the pH of the rumen?
5.5-6.5
192
What is the temperature of the rumen?
38-42 degrees celcius
193
What does the rumen act as?
- A large fermentation vat
- Contains millions of bacteria, fungi and protozoa
194
What does the rumen allow?
Ruminants to extract and absorb nutrients from fibrous plant material
195
What are the byproducts from digestion?
- VFA's = acetic, propionic and butyric acids
- Gases = carbon dioxide and methane
196
What is the retention time of the rumen?
- Fibre particles remain in the rumen from 20 to 48 hours because bacterial fermentation of fibre is a slow process
- Particles that digest faster such as starch tend to stay in the rumen for a shorter period of time
197
What percentage of the total energy and protein does the rumen supply?
60-80%
198
What does the reticulum act as?
- A filter
- Particles leaving the rumen are sorted
199
What shape is the inside of the rumen?
Honeycomb surface
200
How does the reticulum work?
- Cud rechewed and returned
- Only particles that are small in size (< 1-2 mm) and dense (>1.2 g/ml) may move on to the third chamber
- Foreign objects are stored
201
What is rumination?
The regurgitation, rechewing and reswallowing of ingested food
202
What is cud?
Mass of regurgitated ingesta; bolus
203
What is the process of rumination?
1. Regurgitation bolus from rumen
2. Rechew and reinsalivate
3. Reswallow
4. Repeat with another bolus
204
What does the omasum look like?
- Spherical shaped
- Contains various sized leaves
205
What is the omasum for?
- The leaves prevent large particles from leaving the rumen and entering the abomasum
- Lots of layers of tissue which absorb some of the fluid and act as filters so that the food can go onto the fourth and final stage of digestion in the abomasum
206
What is the capacity of the omasum?
- Approx 10 litres
- Great absorptive capactiy
207
What is the pH of the omasum?
6.5
208
What is the abomasum?
- Fourth compartment and same function as the stomach in monogastrics
- The ruminants true or glandular stomach
- It acts like a regular stomach where acid is secreted and many digestive enzymes
209
What is the pH of the abomasum?
2
210
What size is the small intestine?
- 130 foot long
- 2 inches wide
211
What is the purpose of the small intestine?
- Feed mixes with secretions from the pancreas and liver- pH increased from 2.5 to between 7 and 8 (this is necessary for the enzymes to work)
- Enzymatic digestion
- Remaining nutrients are digested
*Proteins to amino acids
*Starch to glucose
*Fats to fatty acids
- Absorption
- Villi on intestinal wall increases surface area for absorption
- Muscular contractions mix the digesta and move it to the large intestine
212
What is the large intestine made up of?
- Caecum
- Colon
- Rectum
213
What are the functions of the large intestine?
- Absorb water
- Microbial activity
- Waster storage
- Primary purpose is to absorb water from the digesta
- Hind-gut bacteria work at digestion food that escaped earlier
- This contributes less than 15% of the total digestion
- Up to 50% of dry weight of faeces can be microbial origin
214
What digestive enzymes are in saliva?
- None
- Important as lubricant and a source of buffers
- A 600kg cow on a forage diet- 170 litres
215
What digestive enzymes are in the rumen?
- None
- Bacteria, fungi and protozoa
216
What digestive enzymes are in the abomasum wall?
- Hydrochloric acid
- Pepsinogen (pepsin once activated)
217
What digestive enzymes are in the small intestine?
- Liver: bile (emulsifies fat)
- Pancreas: lipases and proteases
218
Newborn calfs stomach
- An under developed stomach
- Abomasum makes up 70% of the total volume and the rumen 30%
- No microbes present in the rumen
- As the calf grows, the rumen grows in size, and also the microbes become fully functional
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Reticular Groove
- Suckling action causes the reflex closure of the reticular groove
- Milk, colostrum or milk replacer bypasses reticulo-rumen and enters abomasum directly for digestion
- The formation of the reticular groove is controlled by neural stimulation from suckling (bottle or bucket) and milk proteins
- Casein of milk clotted by action of rennin and acidity in the abomasum
- Feeding milk for an extended time usually results in development of the calf, but limited rumen development because the esophageal groove keeps liquid feeds out of the rumen
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Rumen Development
- The functional rumen acts as a fermentation vat
- The lining of the rumen wall in an adult cow has a very pronounced covering of papillae
- These papillae are finger-like projections, the area through which nutrients can be absorbed
- Papillae development is stimulated by the end products of microbial fermentation
* Specifically butyric acid
* To a lesser extent, propionic acid
- Within a few days of birth, the calfs rumen begins to develop a population of microbes
- The types of rumen microbes that proliferate are those that best digest and utilise the feeds eaten by the calf
- The esophageal groove does not function when the calf eats dry feeds; they enter the rumen, where they must be digested by microbes or chewed further by rumination
- In addition to feeds, the environment, bedding and hair provide microorgnaisms that inoculate the calfs rumen
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Rumen development and the consumption of water and solid feed
- Water, forage and concentrates go into the rumen
- Results in growth of rumen and bacterial population
- However, type and amount of feed important for rumen development
- Fermentation of fiber = higher acetic acid
- Fermentation of starch = higher propionic and butyric
- Fresh free water is essential for rumen microbes to grow properly and ferment feedstuff
- 8 week: rumen is fully developed
- From the standpoint of efficiently and economically feeding dairy replacements, developing the rumen so that it can serve as a fermentation chamber for forages and concentrates is fundamental
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What do microbes require?
- Feeds balanced for energy for energy protein, fibre etc
- Environment free from oxygen
- pH > 6
- Plentiful supply of water
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Rumen microflora
- The rumen provides a suitable environment with generous food supply from microbes to grow and reproduce
- The absence of air (oxygen) in the rumen favours the growth of some particular species of bacteria
- Among them are those that can degrade cell walls (cellulose) into simple sugars (glucose)
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Rumen microbiome
- The microbial community in the rumen is one of the most diverse gut ecosystems yet describes in the animal kingdom
- Increase understanding of:
*Dietary factors that affect it
* The influence of the host on the
microbiome
* The effect of the rumen on the host
- Maximise production and minimise environmental impact
- Microbes play an essential role. Taken together, these microbes are unique in that they are what ferment and digest the fibrous parts of plants, which ruminants could not do on their own
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Rumen microflora
- Feed the rumen first
- The rumen is inhabited by a diverse and immensely complex community of microbes including:
*Bacteria
*Protozoa
*Fungi
*Archaea
*Viruses
- Symbiotic relationship
-Ruminants, unlike humans and other monogastrics get their nutrients (VFAs and microbial protein) largely from rumen microbes (energy substrates from the fermentation of plant fibre and protein directly from digesting the microbes themselves) rather than directly from the diet they eat
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Rumen Microbes
- Complex nature of the feed: Carbs, proteins, fats, other organic compounds and minerals
- Bacteria, protozoa, and fungi exist together in the cows rumen
- Colonization of ingested material
- Synergistic relationship between microbes
- Microbial populations:
*Free in rumen fluid
*Those associated with feed particles and
*Those associated with the rumen wall
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Rumen Microbiology
- Types of organisms present depends on the type of feed being consumed and level of intake
- High forage = high in cellulose and hemicellulose
- High cereal = high starch. Organisms that digest starch will grow
- Cellulolytic bacteria activity accounts for the majority of fibre digestion in the rumen
- These bacteria capture most of the energy from fibre when pH is maintained at or over 6.0
- Amylolytic bacteria digest starch and sugars
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Rumen bacteria classification:
1. Fibre digesters
2. Starch and sigar digesters
3. Lactate using bacteria
4. Hydrogen-using bacteria
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Cellulolytic (fibre digesting) bacteria
- Fibre digesting bacteria produce acetate
- Directly correlated with the amount of fibre
- The fibre digesters are some of the fussiest bacteria in the rumen
- They are very sensitive to acid and fat
- When a cow has acidosis (pH<5.8), the rumen produces a lower proportion of acetate to propionate because the fibre-digesters who primarily make acetate are not working well
- High levels of rumen available fat (generally over 5% of the diet) reduce the growth of the fibre digesters
- Fats coat the fibre particles making it difficult for the fibre digesting microbes to get in to do their work
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Cellulolytic bacterial species growth requirements
- Cellulose
- Hemicellulose
- Pectin
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