1. Literature Review
ANSC 312
Grant Edwards

2. Getting started
Critically discuss whether current grazing systems to low post grazing pasture residuals are restricting intake of dairy cows.
Finding literature
Library database (CAB abstracts)
Google
Find around 10 relevant papers and read them. Use reference list from ‘good’ papers to find more references.
Decide on 2 main topics that you will cover
At end of introduction, state the objectives of the review (what’s covered and what’s not covered)
e.g. The purpose the review is to examine the effect of grazing residuals on DM intake and determine whether current grazing management is restricting intake.

3. Using table/figures Copy and paste tables/figures from the paper
Create your own table using relevant data

4. Copy and paste

5. Create your own
Table 1: Herbage mass (pre- and post-grazing), post-grazing height and daily herbage intake of pasture grazed by dairy cows in two grazing systems that assessed the effects of herbage allowance (Experiment 1) or grazing severity (Experiment 2). (From Mayne et al., 1987)
Experiment 1
Experiment 2
Residual sward height
Low
Medium
High
s.e. mean
Severe
Moderate
Lax
Herbage mass
Pre-grazing (OM/ha)
3480
3760
3730
155.3 NS
2430
2410
3940
178.9 ***
Post-grazing (OM/ha)
1850
2210
2370
80.7 ***
990
1340
2590
213.9 ***
Post-grazing height (mm) 42 51 59
0.9 *** 49 60 87
Daily herbage intake
Period I
8.9
10.2
11.1
4.6 NS
10.22
10.85
13.02
0.505 **
Period II
6.6
9.9
10.5
2.51 NS
11.35
12.26
11.09
0.44 NS
Period III
8.1
9.5
2.12 NS
Overall
7.9
1.13 NS
10.8
11.5 12
0.49 NS
s.e. mean = standard error of the mean
NS=not significant; * = P<0.05; **=P<0.01 and ***=P<0.001

6. Statement
Low post-grazing residuals can restrict daily dry matter intake and limit animal productivity.
Example
Mayne et al., (1987) found that cows grazing to high residuals (>60mm) had higher dry matter intakes (10kg OM/cow/day) than cows grazing to low residuals (<60mm; 13kg OM/cow/day) (Table 1). In a 10 day study by Lee et al., (2008) dairy cows were given the same allowance above a pre determined post-grazing height. In this case the daily dry matter intake was similar between three treatment groups (14.8 kg DM/cow/day). Mayne et al., (1987) used grazing severity and pasture allowance to achieve different post grazing residuals however Lee et al., (2008) separated these factors by having the same pasture allowance between treatment groups.

7. Explain
Low post grazing residuals may not be the only factor contributing to restricted intakes in dairy cows. Other factors such as pasture allowance may contribute to the effects of post grazing residual on dry matter intake and animal performance.

8. Citing references
Low post-grazing residuals can restrict daily dry matter intake and limit animal productivity. Mayne et al., (1987) found that cows grazing to high residuals (>60mm) had higher dry matter intakes (10kg OM/cow/day) than cows grazing to low residuals (<60mm; 13kg OM/cow/day) (Table 1). In a 10 day study dairy cows were given the same allowance above a pre determined post-grazing height (Lee et al., 2008) . In this case the daily dry matter intake was similar between three treatment groups (14.8 kg DM/cow/day). Mayne et al., (1987) used grazing severity and pasture allowance to achieve different post grazing residuals however Lee et al., (2008) separated these factors by having the same pasture allowance between treatment groups. Low post grazing residuals may not be the only factor contributing to restricted intakes in dairy cows. Other factors such as pasture allowance may contribute to the effects of post grazing residual on dry matter intake and animal performance.

9. Referencing Use the New Zealand Society of Animal Production style
A study by Mayne et al., (1987) showed that....
An increase in herbage allowance corresponded to an increase in post-grazing height and an increase in dry matter intake (Mayne et al., 2003)

10. Referencing
Brown AB, Black BC Title of paper. Name of Journal Volume: page-numbers Lee JM, Donaghy DJ, Roche JR Short communication: Effect of Postgrazing residual pasture height on milk production. Journal of Dairy Science 91: Mayne CS, Newberry RD, Woodcock SCF, Wilkins RJ Effect of grazing severity on grass utilisation and milk production of rotationally grazed dairy cows. Grass and Forage Science 42: 59-72