Genetic Parameters for Milk Somatic Cell Scores and Relationships with Production Traits in French Lacaune Dairy Sheep

Rupp, Rachel; Lagriffoul, Gilles; Astruc, Jean‐Michel; Barillet, Francis F.

doi:10.3168/jds.s0022-0302(03)73732-1

Cited by 52 publications

(56 citation statements)

References 21 publications

(36 reference statements)

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“…Heritability estimates, based on repeatability test-day models, range from 0.04 to 0.16 for several breeds including the Churra (Baro et al, 1994;El-Saied et al, 1998;Othmane et al, 2002), the Manchega (Serrano et al, 2003), the East Friesian (Hamann et al, 2004) and the Valle del Belice sheep breeds (Riggio et al, 2007). Other studies reported similar or slightly higher heritability estimates (from 0.11 to 0.18) for the average SCS during lactation, for Chios (Mavrogenis et al, 1999), Lacaune (Barillet et al, 2001;Rupp et al, 2003a), Latxa (Legarra and Ugarte, 2005) and Manech Red Faced ewes (Barillet et al, 2008). These heritability estimates are comparable to those reported in literature for cattle either with test-day (Carnier et al, 1997;Mrode et al, 1998) or lactation models (Rupp and Boichard, 1999).…”

Section: Genetic Parameters Of Scc and Mastitis In Sheepmentioning

confidence: 66%

Genetic selection for reduced somatic cell counts in sheep milk: A review

Riggio

Portolano

2015

Small Ruminant Research

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a b s t r a c tMastitis is an inflammation of the udder, mainly caused by bacteria, and leads to economic loss, due to discarded milk, reduced milk production, reduced milk quality and increased health costs in both dairy sheep and cattle. Selecting for increased genetic resistance to mastitis can be done directly or indirectly, with the indirect selection corresponding to a prediction of the bacteriological status of the udder based on traits related to the infection. The most frequently used indirect method is currently milk somatic cell count (SCC) or somatic cell score (SCS). This review reports the state of the art relating to the genetic basis of mastitis resistance in sheep and explores the opportunities to use SCC as selection criterion in a breeding programme to improve resistance to mastitis in sheep, discussing the actual situation and prospects for improvement. It has been stressed, in particular, that although it is unlikely that selection for mastitis resistance by the farmers on their own will be successful, there is good prospect for genetic improvement if reliable pedigree and performance recording is implemented across flocks, combined with breeding value estimation. To achieve this, a strong and well-structured organization to implement and support the programme is essential.

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Section: Genetic Parameters Of Scc and Mastitis In Sheepmentioning

confidence: 66%

Genetic selection for reduced somatic cell counts in sheep milk: A review

Riggio

Portolano

2015

Small Ruminant Research

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“…These are still a matter of discussion, as estimates in the Lacaune breed are unfavourable, whereas estimates in the Spanish breeds are favourable (e.g. Rupp et al (2003) and Legarra and Ugarte (2005) and references therein) but we have shown that for different estimates either economic weights or a desired gains index are adequate, the latter being slightly economically worse. Yet one needs to be careful not to set too strong a restriction for the change in SCS, because the risk of greatly diminishing gains for milk yield exists depending on the true genetic parameters.…”

Section: Discussionmentioning

confidence: 86%

“…Legarra and Ugarte (2005) estimated in the Latxa breed heritabilities of 0.21 for milk yield and 0.13 for SCS, and a (favourable) genetic correlation of 20.30. Rupp et al (2003) estimated in the Lacaune breed a genetic correlation that turns out to be unfavourable (between 0.08 and 0.18). The pseudo-economic weight was calculated to fix, under these conditions, the genetic change of SCS to zero.…”

Section: Sensitivity Analysismentioning

confidence: 98%

“…The logarithm is expressed in base two, which means that an increase of one in the SCS scale implies doubling in the SCC scale. Many studies exist on the genetic background of SCS in dairy sheep; for references, see Rupp et al (2003). The economic weight will be therefore calculated on the Ali and Shook (1980) SCS scale, as the simplest one, and the scale in which estimated breeding values are calculated and presented.…”

Section: Traitsmentioning

confidence: 99%

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Economic weights of somatic cell score in dairy sheep

Legarra

Ramón

Ugarte

et al. 2007

Animal

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The economic weights for somatic cell score (SCS) have been calculated using profit functions. Economic data were collected in the Latxa breed. Three aspects have been considered: bulk tank milk payment, veterinary treatments due to high SCS, and culling. All of them are non-linear profit functions. Milk payment is based on the sum of the log-normal distributions of somatic cell count, and veterinary treatments on the probability of subclinical mastitis, which is inferred when individual SCS surpass some threshold. Both functions lead to non-standard distributions. The derivatives of the profit function were computed numerically. Culling was computed by assuming that a conceptual trait culled by mastitis (CBM) is genetically correlated to SCS. The economic weight considers the increase in the breeding value of CBM correlated to an increase in the breeding value of SCS, assuming genetic correlations ranging from 0 to 0.9. The relevance of the economic weights for selection purposes was checked by the estimation of genetic gains for milk yield and SCS under several scenarios of genetic parameters and economic weights. The overall economic weights for SCS range from 22.6 to 2 9.5 e per point of SCS, with an average of 2 4 e per point of SCS, depending on the expected average SCS of the flock. The economic weight is higher around the thresholds for payment policies. Economic weights did not change greatly with other assumptions. The estimated genetic gains with economic weights of 0.83 e per l of milk yield and 24 e per point of SCS, assuming a genetic correlation of 20.30, were 3.85 l and 2 0.031 SCS per year, with an associated increase in profit of 3.32 e. This represents a very small increase in profit (about 1%) relative to selecting only for milk yield. Other situations (increased economic weights, different genetic correlations) produced similar genetic gains and changes in profit. A desired-gains index reduced the increase in profit by 3%, although it could be greater depending on the genetic parameters. It is concluded that the inclusion of SCS in dairy sheep breeding programs is of low economic relevance and recommended only if recording is inexpensive or for animal welfare concerns.

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“…Sub-clinical mastitis is generally diagnosed by an increase in somatic cell counts (SCC) in the milk. Although heritability for mastitis (,0.04) and SCC (0.11) in dairy cattle is low, the genetic correlation between the two is high (,0.70), so that SCC can be conveniently used in selection index to reduce the incidence of mastitis in cows (Mrode et al, 1998;Heringstad et al, 2000;Colleau and Regaldo, 2001;Willam et al, 2002) and ewes (Barillet et al, 2001;Rupp et al, 2003). These examples show the potential of genetic selection and significant progress may be made by the exploration of the molecular polymorphism responsible for these genetic effects on susceptibility to disease.…”

Section: Introductionmentioning

confidence: 99%

Minimising pain in farm animals: the 3S approach – ‘Suppress, Substitute, Soothe’

Guatteo

Levionnois

Fournier

et al. 2012

Animal

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Recently, the French National Institute for Agricultural Research appointed an expert committee to review the issue of pain in food-producing farm animals. To minimise pain, the authors developed a ‘3S’ approach accounting for ‘Suppress, Substitute and Soothe’ by analogy with the ‘3Rs’ approach of ‘Reduction, Refinement and Replacement’ applied in the context of animal experimentation. Thus, when addressing the matter of pain, the following steps and solutions could be assessed, in the light of their feasibility (technical constraints, logistics and regulations), acceptability (societal and financial aspects) and availability. The first solution is tosuppressany source of pain that brings no obvious advantage to the animals or the producers, as well as sources of pain for which potential benefits are largely exceeded by the negative effects. For instance, tail docking of cattle has recently been eliminated. Genetic selection on the basis of resistance criteria (as e.g. for lameness in cattle and poultry) or reduction of undesirable traits (e.g. boar taint in pigs) may also reduce painful conditions or procedures. The second solution is tosubstitutea technique causing pain by another less-painful method. For example, if dehorning cattle is unavoidable, it is preferable to perform it at a very young age, cauterising the horn bud. Animal management and constraint systems should be designed to reduce the risk for injury and bruising. Lastly, in situations where pain is known to be present, because of animal management procedures such as dehorning or castration, or because of pathology, for example lameness, systemic or local pharmacological treatments should be used tosoothepain. These treatments should take into account the duration of pain, which, in the case of some management procedures or diseases, may persist for longer periods. The administration of pain medication may require the intervention of veterinarians, but exemptions exist where breeders are allowed to use local anaesthesia (e.g. castration and dehorning in Switzerland). Extension of such exemptions, national or European legislation on pain management, or the introduction of animal welfare codes by retailers into their meat products may help further developments. In addition, veterinarians and farmers should be given the necessary tools and information to take into account animal pain in their management decisions.

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Genetic Parameters for Milk Somatic Cell Scores and Relationships with Production Traits in French Lacaune Dairy Sheep

Cited by 52 publications

References 21 publications

Genetic selection for reduced somatic cell counts in sheep milk: A review

Genetic selection for reduced somatic cell counts in sheep milk: A review

Economic weights of somatic cell score in dairy sheep

Minimising pain in farm animals: the 3S approach – ‘Suppress, Substitute, Soothe’

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