Dairy Sheep Symposium - the Department of Animal Sciences ...

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dairy cattle industry and is certainly not backed up by government funding as the French system is. Alternative solutions have to be found and a Group Breeding Scheme could very well be what the industry needs. Group Breeding Scheme A Group Breeding Scheme is a group of producers with a common selection goal where breeding stock is selected and shared among the members of the group. By increasing the number of animals in the selection pool, using EPDs and sharing the best rams, the group of producers increases the rate of genetic gain over purchasing sheep from outside flocks or from selecting solely within their own flock. A Group Breeding Scheme uses a team of common sires over a group of flocks in order to create genetic links between member flocks. With genetic links between flocks, it becomes possible to compare animals between flocks regardless of the environmental differences between flocks, management, nutrition or other non-genetic effects, and EPDs can be calculated. An EPD is an estimate of the genetic value of an animal calculated from performance information from all relatives of that individual and is the most accurate estimate of genetic value possible. An EPD calculation for a prospective ewe or ram replacement would use the milk yields (or any other trait) of the individual’s dam, maternal grand-dam, paternal grand-dam, full-sisters, halfsisters, and any other female relatives with milk production records. Rams with the highest EPD become reference rams and are used on a certain percentage of ewes (generally the ones with the highest EPDs) of each member flock either with natural mating or, better yet, with artificial insemination. The conditions of use of the rams and rewards to the owner of the rams (payment, time of use, cost, etc…) need to be sorted out by the group of producers. EPD calculations require relatively sophisticated statistical techniques and fairly large computing resources. EPDs are currently calculated by the National Sheep Improvement Program (US) and by the Record of Performance Program (Canada) on a few meat breeds. It would be up to a group of sheep dairy producers to form an association and to work with NSIP (or another entity) for the calculation of milk production EPD A Sire Reference Scheme is not a new concept since most selection schemes use the similar principles of a nucleus population and diffusion of genetic improvement throughout the base population. New Zealand, however was the pioneer in the use of group breeding schemes in sheep and achieved rather good results on meat and wool breeds. Some similar breeding programs are being developed in other countries (Spain for instance) on commercial dairy sheep operations. How does a Group Breeding Scheme work? First step. A group of producers with a set of common goals get together with the purpose of genetically improving their flock. By-laws should be clearly defined to which all members should abide. Rewards to the producers of the best rams used by the group should be spelled out to eliminate all possible controversies. Selection criteria should be well chosen and agreed upon by all members. Generally, in dairy sheep production, milk yield is the primary selection criterion. However, since practically all sheep milk is transformed into cheese, fat and protein percentages are extremely important for cheese yield and high quality products. In North America a good level of production has been obtained by crossbreeding with the East Friesian. However, this higher level of production has resulted in lower fat and protein percentages in the milk because of the negative correlation between production and components. It would seem essential that fat and protein content should be included as selection criteria as soon as possible.
Second step. All members enroll in NSIP or ROP or any other entity that would be able to calculate EPDs. Members keep accurate records on pedigree, milk production, milk composition and on any other traits that the group decided upon. Recording of milk production should be standardized and performed by a third party such as the Dairy Herd Improvement Program. ICAR (International Committee for Animal Recording) has set definite rules for the recording of ewe milk production. Third step. During the first 2-3 years, a set of common sires, chosen as best as possible, is used on all member flocks in order to create genetic links between flocks, which is the essential condition for the possible comparison of animals between flocks. Meanwhile intra-flock EPDs are calculated on ewes of each flock in order to determine the best 20% ewes, which would form a sort of loose nucleus in each flock. The percentage of ewes to form the nucleus is determined according to the number of ewes involved in the breeding group and will be the same for each flock. The higher the number of ewes in the group, the lower the percentage needed for the nucleus, resulting in a higher intensity of selection. The advantages of a nucleus are two folds: - Only the ewes of the nucleus need to have a strict record keeping system, lowering the overall cost. - Artificial insemination can be done only on the nucleus ewes. - As soon as the genetic link is created, the real genetic improvement will start. Fourth step. The semen of the best between-flock EPD young rams is collected and used fresh or frozen for the insemination of the nucleus or “elite” ewes of each flock. The number of rams to use will depend on the number of “elite” ewes in the group. The rest of the ewes (or base flock) can be bred naturally by any rams of the producer’s choice (generally with second best EPD’s). “Elite” ewes are replaced by the best EPD ewe lambs born from elite ewes. The second best ewe lambs are used to replace ewes of the base flock. The best ram lambs from the elite group join the ram pool and are progeny tested. Some of them would become “proven” rams, the others are sold. Subsequent years. Half of the “elite” ewes of each flock are inseminated with “proven” rams and 1/2 are inseminated with promising young rams for progeny testing. Therefore, a typical pyramidal structure is formed in each flock as shown in figure 2. Another possible system would be for all producers to pool their best ewes together in one flock to form a nucleus flock. This “elite” flock can be managed by one of the members who would also take care of the pool of rams. All “proven” rams and promising young rams as well as some replacement ewes will come from this nucleus flock. This system works extremely well and requires the least amount of work from each member. The producer member taking care of the nucleus flock is compensated for his extra work and expenses by a higher milk production of this elite group.
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Proceedings of the 7 th Great Lakes
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ORGANIZING COMMITTEE 7 TH GREAT LAK
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Thursday, November 1 Noon Registrat
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SPEAKERS Dr. Juan-José Arranz, Dpt
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Table of Contents (continued) Lates
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eeding and were created to have hig
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Disease in the U.K. and subsequentl
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sheep production conditions in Wisc
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Pinelli, F., P. A. Oltenacu, G. Ian
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Bucket milking and elevated platfor
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Throughputs in different parlors No
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1 - Stand up as straight as possibl
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Roques J.L.. 1997. Traite des brebi
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Grade B milk quality is as follows:
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(c) Not Applicable (d) At least 10
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TOILET AND WATER SUPPLY 7. Toilet (
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(c) Drugs and medicinals shall be l
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FARMSTEAD CHEESE AND MARKETING Stev
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5. Cheese is delivered in person, w
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to participate with us, we are enga
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The key points to this plan were: Y
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Milk is supplied in two major forms
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MANAGEMENT OF A DAIRY SHEEP OPERATI
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4 3.5 3 2.5 2 1.5 1 0.5 Chart 1: Mi
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Facilities and Equipment The requir
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from the ewes at 12 to 24 hours of
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COMPARISON OF EAST FRIESIAN AND LAC
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two-year-olds in 2001. East Friesia
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Reproduction. Table 4 compares the
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six ewes were sired by Lacaune ram
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FACTORS AFFECTING THE QUALITY OF EW
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Sheep Genetic factors breed and gen
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Genetic factors The breed and genot
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Physiological factors affecting she
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Management factors affecting the qu
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sheep with one peak of milk ejectio
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An important aspect of dietary fibr
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References Alais C. (1974). Science
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Bufano G., Dario C. and Laudadio V.
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Cowan R.T., Robinson J.J., McHattie
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Folman Y., Volcani R. and Eyal E. (
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Kalantzopoulos G. (1994). Influence
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McHattie I., Fraser C., Thompson J.
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Peart J.N. (1970). The influence of
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Ranieri M.S. (1993). La variazione
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Treacher T.T. (1970). Effects of nu
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EVALUATION OF SENSORY AND CHEMICAL
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ing, the cheeses were brined for 18
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The FFA concentrations generally in
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Table 1. Composition of pasteurized
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Table 6. Body and texture scores 1
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Present Development of Selection Sc
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Breed Usage in Europe Crossbreeding
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nearly 1. As a consequence this cha
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Table 5. Repeatabilities and phenot
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percentage is not expected to resul
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Improved AI technique Artificial in
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Identifying major genes or QTL rela
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Figure 5. Half-sib families and QTL
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In the case of cheese the problem i
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Emanuelson, U., Danell, B., Philips
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Rothschild, M. F., Soller, M. (1997
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teat placement in dairy ewes (Fern
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that of the average milking time. M
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1988) and active expulsion of fat f
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References Barillet, F., and F. Boc
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Table 1. Least squares means ± SEM
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Table 3. Simulation of parlor throu
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EFFECT OF REDUCING THE FREQUENCY OF
Page 140 and 141: Individual ewe milk production (mor
Page 142 and 143: dimanche soir sur les brebis de rac
Page 144 and 145: A B A Morning milk yield, kg B Adj.
Page 146 and 147: Background and History: Most sheep
Page 148 and 149: Percent 100 80 60 40 20 0 87 Effect
Page 150 and 151: Fall Lambing Percentage 100 90 80 7
Page 152 and 153: THE EFFECT OF GROWTH RATE ON MAMMAR
Page 154 and 155: After puberty, the mammary gland re
Page 156 and 157: Many trials have examined the mamma
Page 158 and 159: From these results the authors conc
Page 160 and 161: Onset of Puberty and Reproductive P
Page 162 and 163: Similarly, calves, heifers, and cow
Page 164 and 165: McCann, M. A., Goode, L., Harvey, R
Page 166 and 167: DISCUSSION Stability of Frozen Raw
Page 168 and 169: analyzed for titratable acidity, sy
Page 170: 411-416. Wendorff, W.L. 1998. Updat
Page 175 and 176: Recent Outbreaks involving Cheddar
Page 177 and 178: testing on raw milk at the farm. Th
Page 179 and 180: THE AUSTRALIAN SHEEP DAIRY INDUSTRY
Page 181 and 182: The University of Western Australia
Page 183 and 184: Heterosis did not seem to intervene
Page 185 and 186: Lambs The problem of weaning lambs
Page 187 and 188: GROUP BREEDING SCHEME: A FEASIBLE S
Page 189: Where: h = square root of heritabil
Page 193 and 194: The structure and movement of anima
Page 195 and 196: CAN THE OVARY INFLUENCE MILK PRODUC
Page 197 and 198: dividing the amount of milk obtaine
Page 199 and 200: the CL there were significant diffe
Page 201 and 202: etween milkings. Finally, this woul
Page 203 and 204: Table 1. Least squares means ± SEM
Page 205 and 206: A Daily milk yield (kg) A B Milk fl
Page 207 and 208: Progesterone (ng/ml) 8 6 4 2 0 CLY:
Page 209 and 210: milk volume within the cistern (Mar
Page 211 and 212: Results Treatment milk yield increa
Page 213 and 214: Reports in dairy cattle concerning
Page 215 and 216: Muir, D.D., D.S. Horne, A.J.R. Law,
Page 217 and 218: Milk yield (kg) 1.4 1.2 1.0 0.8 0.6
Page 219 and 220: A Milk protein (%) A A Milk protein
Page 221 and 222: TAPPE FARM TOUR Jon & Kris Tappe, T
Page 223: a little special attention every da
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