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A COMPARISON OF TWO WINTER MANAGEMENT SYSTEMS FOR DRY DAIRY CATTLE
A thesis presented in partial fulfilment. of the requirement
for -t'lo degree of Master of Agricultural Science in Animal
Science at Massey University, ·Palmerston North, New Zealand
Lession L.M. Ngigwana
1976
ABSTRACT
Two management systems for dry dairy cows were studied during the winter of 1975 at No. 3 Dairy Unit, Massey University. The
objective of the study was to help develop a system which may reiuce the need for supplementation of pasture grown, and at the same time ensure that adequate feed supplies are available over the winter and early spring to meet animal requirements.
The parameters studied were pasture grow·th rates and recovery, pasture damage through pugging, feed consumption and live weight changes of cows, milk production for the first three months of lactation, and the grass 'cover' on the two farmlets.
In general, the results have shown that each system he.d its ovm advantages and disadvantages and these are discussed in the text.
It is, however, recommended that while such advantages and disadvantages exist, a grazing system which incorporates the two systems warrants
eA�erimentation. In addition, better methods of �easuring pasture growth rates and grass 'covers' deserve further investigation.
ACKNO\'ILEOO.EMENTS
I am greatly indebted to my Supervisors, Dr A.W.F. Davey and Dr G.F. Vlilson for their guidance and encouragement in achieving this work. Special thanks to Dr G.F. Wilson for checking all the results and helping me make the necessary alterations while Dr A.W.F. Davey was on overseas leave.
I am also grateful to the Department of Dairy Husbandry, Massey University for providing the area and stock used in the experiment. In addition to the staff of Dairy Unit No. 3, i.e. the Manager and his assistant, in feeding and shifting the cows. R.J.
McClenaghan for his technical assistance in using the equipment and Mr R. Hodren for supplying the information on No. 3 Dairy Unit.
I am also grateful to Professor D.S. Flux for his initial advice of tackling the massive work, Professor B.R. Watkin and Dr C. those who have contributed in the discussion. Vi. Holmes for some valuable discussion. Thanks are also due to
I would like to thank the Library staff for their valuable help in obtaining the references. Thanks are also due to Mrs J.A.
Jepson for her careful and diligent typing of this thesis.
Much appreciation is accorded to the New Zealand Government for granting the scholarship (Special Commonwealth African Assistance Plan - SCAAPthis work would not have been undertaken. ) and the Tanzanian Government for nomination without which
Lastly special thanks to·my family, particularly my wife, for being so patient and encouraging me throughout the two and a half years I have been away from home. Also thanks to all friends here in New Zealand who encouraged me so much to finish this work within the time.
1 2
3
TABLE OF CO.NTENTS
Introduction • • Review of Literature
2 : 1 2 : 2
Objectives of wintering dairy cows on a seasonal dairy farm
Cows' requirem ents ..
Energy requirements for maintenance E nergy requirements for pregnancy • •
\'!eight of cows before calving 2 : 2 : 1
2 : 2 : 2 2 : 2 : 3
2 : 2 : 4 Total energy requirements for mai nte nance, pre gnancy and some live weight gain
2 : 3
2 : 4
2 : 5
Factors which affect grass production 2 : 3: 1
2 : 3 : 2 2 : 3 : 3
Climat ic factors Soil fA.ctors • . r.�anagement factors 2 : 3 : 3 : 1
2 : 3 : 3 : 2 Grazing management
Other r:anagement f<'.ctors
. .
Assessment of feed quantity and feed budgeting 2 : 4 : 1
2 : 4 : 2 Methods of assessiYJ.g feed quantity Feed budgeting
2�4: 2 : 1 2 : 4: 2 : 2 2 : 4: 2 : 3
?.'ethods of feed budgeting
Reconciliation of feed sup�lies
and stock requirements Adjustment to feed suppli es Wintering systems
2 : 5: 1 Block or strip/bre�( grazi ng or paddock wintering systems
2 : 5 : 2 O�off system
2 : 5 : 3 Set st ocki ng Experimental methods
3: 1 Introd�ction
3 : 2 Experimental procedures
3: 2 : 1 The Trial
3 : 2 : 2 Start of the trial 3 : 2 : 3 Measurements • •
. .
. .
. .
3 : 2 : 3 : 1 Assessment of dry matter in each paddock, or per hectare before
grazing ..
3: 2 : 3: 2 Assessment of grass consumed i n
each paddock ..
3 : 2 : 3: 3 Live wei ght measurements ..
3: 3 : 3 : 4 Assessment of pasture growth rate and pasture damage by pug�ng
Page No . 1
3 3 4 1 0 6 1 1 1 2 1 4 1 5 1 7 1 8 1 8 22 24 24 26
27 28 27 29
30 30 32 33 33 33 35 34 36
36 .38 37 38
3 : 2 : 4 Statisti cal Analysis
4 Results of the Experiment
4 : 1 Grass Budgets
!1-: 2 Calibration of the re ter
4: 3 Pasture 5rowth r�tes
4 : 3 : 1 4 : 3 : 2 4 : 3 : 3
Regrowth following grazing
Pasture growth rates in relation to DJvl
remaining after grazing
Pasture grovrth rates G.nd l'Ccovery in trodden and heavily pugged paddocks
4 : 4 Intake and production • • L1-: L1-: 1
4 : 4 : 2 4 : 4: 3
The amount of feed consumed
Relation between the measured daily intakes and live weight changes
Average milk production for the first three months of lactation
4 : 5 ·:.'ccrmlet comparisons
4 : 5 : 1 4 : 5 : 2 4 : 5 : 3
The amount of grass {!}:OWn on each farmlet Comparison of me::J.sured intakes and growth rates vli th budgeted (predicted) estil"lates Comparison of measured and predicted grass covers on the farmlets
Pasture damage
5 General Discussion
5 : 1 The validity of the techniques used to measure dry matter yields • •
5 : 2 The grass budgets
5 : 3 Pasture t;rowth rates
5 : 3 : 1 5 : 3 : 2
Growth rates of pasture following grazing Pasture growth rates on a farmlet basis
5 : 4 Intake and animal production
5 : 5 Fermlet comparison Summary
Appendices References
(r•)
Page No.
39
44 44 44
48 48 53 55 55 55 6 2 69 69 69 71 71 76 77
77 79 80 80 81
82 84 88 90
124
4.2
4.3
4.4
4.5a
4.5b
4.6b
lJ-. 7 4.8
LIST OF TABLES
Linear regression equ�tions obteined for each month during the tri�l period • •
Co�parison of grass covers on the farmlets in June determined usine either the linee_r regression or
curvilinear calibrA-tion curve • • Growth rates of grazed pastures
Pasture crovrth rates following grazing classified
according to p.qsture D�� present at the beginning of four periods of three weeks • •
Amount of feed eaten by cows as gr::tss and hay per paddock (kg D?,l/ha/ day) • •
��otal hay consumed on each f'arn:let (Treatment)
Live weight chA.nges ana. measured daily intakes of
cows
'.'Jeekly average live weight changes of 'old' and 'newly' bought heifers
Average daily milk production of cows
Total gr�ss grown .e.nd constuned on the two fe.rmlets between 29.4.75 and 5.7.75 (kg DM)
4.9 a & b Comparison of measured intakes and pasture growth
rates with the values used in the budget
4.10 Comparison of predicted �na neasured grass covers on the two farmlets obt�ned by curvilinear
calibration curves • • . .
4.11 The area pugged by the on-group (only the paddocks pugged heavily are presented) • •
•
lv)
Page No.
46
53
60 62 65 68
70 72
73 76
2.I 2.II
4-.J 4-.II 4-.III 4-.IV
4-.V 4-.VI 4-. VII 4-.VIII 4-.IX 4-.X
(\J�)
LIST OF FIGURES
Partitioning of nutrients in a dairy cow ..
Page No.
5 Growth rates of pasture with 'no nitrogen'
Predicted grass covers on the two farmlets A and B
Calibration curves of grass meter readings and yield of pasture obtained by cutting
Accumulated growth curves of pasture during the
trial period ..
4-.IV a Growth rates of grazed pastures during the trial period (first 21 days) • • 4.IV b Growth rates of pastures during the trial
16 45 47 49
51
peri·-d (second 21 days) • • 52
4-.IV c 10 cm mean soil temperature (winter 1975) 54 4.IV d CUIT.ulative growth of pasture for two paddocks
(paddocks 1 1 and 17) which were not grazed
during the trial period 59
r.:ean live weight changes of the cows during the
experiment ..
Mean live weight changes of mature cows and heifers ('new', 'old' and 'all' heifers)
Relationship be�veen average live weight change and estimated average daily intakes for the o�off group Relationship between average live weight change and estimated average daily intakes for the on-group The anticipated 'grass covers' as compared to the measured 'grass covers'
Grass covers on individual paddocks determined on 5.5.75 using the grass meter (linear calibration regression) • • • • • • • •
..
..
63 64 66 67 74
75
I
II III rv V VI
LIST OF PLATES
Grass rationing to on-group using moveable electric fences • •
Cutting a paddock to ground level before grazing Clipping a grazed paddock to ground level
Putting the clipped grass in plastic bags The grass meter on concrete flo or
Measuring grass cover using grass meter
VII A & B Wet and dry breaks
VIII
IX X XI XII
XIII
Heavily pugged break Two days after pugging
Twelve days after heavy pugging Trampling and fouling of grass
Cows in paddock 23. They are in satisfactory condition
Grass recovery fifteen days after grazing in mid-July
Page No.
4-0
41 41
42 42
43 43
56 56 57 57 58
I II III
IV V VI
VII
APPENDICES
Experimental Layout • •
Predicted Feed Budgets for two Farmlets . .
Dry matter determination from each paddock using the Mas sey Grass N!eter (April, May, June and July)
Regrowth on Grazed Paddocks
Estimation of DM c on sumed/cow/day on paddock basi s Metereological Data as recorded by Massey University , Palmerston North
Dry Matter estimation by cutting and visual apprai sal
Page No.
90 91
97 105 112 118 121
