Dairy Sheep Breeds Research Articles

Economic Values for Dairy Sheep Breeds in Slovakia

Economic values of 14 production and functional traits for two Slovak dairy sheep breeds (Improved Valachian and Tsigai) were calculated. Semi-extensive production systems with one lambing per year were simulated using a bio-economic deterministic computer model. The marginal economic value of a trait was defined as the partial derivative of the profit function with respect to that trait. The relative economic value expressed the percentage proportion of standardized economic value (marginal economic value×genetic standard deviation) of a trait in the sum of the absolute values of the standardized economic values over all traits. Milk yield was of highest relative importance (26% and 32% in Improved Valachian and Tsigai) followed by productive lifetime and conception rate of ewes (16% and 15% in Improved Valachian and Tsigai, in both traits). Conception rate of female lambs and litter size had nearly the same relative economic importance in both breeds (9% to 11%). Survival rate of lambs at lambing and till weaning reached slightly lower economic values (4% to 7%). The economic importance of all remaining traits was less than 4%. (Key Words : Dairy Sheep, Economic Weights, Milk Production, Functional Traits, Improved Valachian, Tsigai)

Covariance components by a repeatability model in Slovenian dairy sheep using test-day records

The estimation of covariance components for daily milk yield, fat and protein content was performed in three Slovenian dairy sheep breeds (Bovec, Improved Bovec, and Istrian Pramenka). In the period 1994–2002, 38 983 test-day records of 3 068 ewes were collected according to ICAR regulations (method A4). All the available relationships between animals were considered. For that reason, information on 3 534 animals was included. Test-day records were analysed by a multiple-trait repeatability animal model. In its fixed part, the model contained breed and season of lambing as classes. Days after lambing, parity, and litter size were treated as covariates. Days after lambing were modelled with modified Ali-Schaeffer’s lactation curve, parity with quadratic, and litter size with linear regression. The random part of the model consisted of flock-test month effect, additive genetic effect, permanent environment effect over lactations, and permanent environment effect within lactation. Covariance components were estimated using the restricted maximum likelihood method (REML). The estimated heritabilities were 0.11 for daily milk yield, 0.08 for fat content, and 0.10 for protein content. A relatively high variance ratio for all milk traits was explained by the flock-test month effect (from 0.27 for daily milk yield to 0.57 for protein content), while ratios explained by both permanent environment effects were lower (up to 0.13). Additive genetic correlations between daily milk yield and fat content, and daily milk yield and protein content were negative and similar (–0.36 and –0.37). A high and positive (0.67) additive genetic correlation between fat and protein content was found. Correlations for environmental effects showed a pattern similar to additive genetic correlations. Genetic parameters estimated in Slovenian dairy sheep showed that genetic progress in milk traits could be achieved using test-day milk records.

Milk yield and composition in line 05 dairy ewes as related to somatic cell counts

1. The relationship between somatic cells and milk traits, and their variation in dairy sheep breeds in Slovakia M. Oravcová, L. Mačuhová, V. Tančin Journal of Animal and Feed Sciences CrossRef

Evaluation of connectedness in the registered population of the Sardinian dairy sheep breed

Connectedness across flocks of the registered population of the Sardinian dairy sheep breed was evaluated Used criteria were :number of sires used in the same contemporary group; number of direct links and the average within and between contemporary group relationship coefficients Dataset including yearlings’ first lactation records of 1990 and 2008 were compared to evaluate the effect of coupling artificial insemination with controlled natural mating on connectedness. An increase of number of sires and direct links were registered between 1990 and 2008. These results confirm that the across years prolonged use of well planned moderate rates of artificial insemination had a strong effect on the overall statistical connectedness across flocks so permitting more accurate estimations of the management and genetic effects As a whole, the decreasing of the average relationship within flock coupled to a marked enhance of the average relationship between contemporary groups, indicates that the genetic connectedness of the Sardinian registered population presents a clearly increasing trend. This fact assures that current genetic evaluations are reliable across flocks.

Genetic relationships between Spanish Assaf (Assaf.E) and Spanish native dairy sheep breeds

At present, the Assaf is the main dairy sheep in Spain. The Spanish Assaf (Assaf.E) was formed by male-mediated absorption of native Spanish sheep. Here we assess the genetic relationships among the Assaf.E and major native Spanish dairy breeds using microsatellites to contribute to the knowledge of the formation and within-population genetic variability of the breed. Blood samples from 44 unrelated Assaf.E individuals from 23 different Assaf.E flocks spread throughout 6 different Spanish provinces were obtained and genotyped using 14 microsatellites. Up to 312 additional samples belonging to the Awassi and Milchschaf sheep breeds and to six native Spanish dairy sheep breeds (Castellana, Churra, Latxa, Manchega, and Rubia de El Molar) as well as samples from Merino individuals to be used as the outgroup were also analysed observed ( H o) and expected ( H e) heterozygosity, rarefacted number of alleles per locus and distances based on molecular coancestry information were computed. Probabilities of assignment of the Assaf.E individuals to native Spanish dairy sheep breeds and cryptic genetic structure in the whole dataset were also assessed. It can be concluded that the Assaf.E breed has low genetic variability and high genetic distance with respect native Spanish dairy sheep breeds. From our results, the formation of the Assaf.E breed basically occurred via the absorption of individuals belonging to the Entrefino type, particularly to the Castellana and Manchega populations. Furthermore, Churra individuals may have participated in the formation of the Assaf.E breed at an early moment of the introduction of the breed into Spain.

Saving threatened native breeds by autonomous production, involvement of farmers organization, research and policy makers: The case of the Sicilo-Sarde breed in Tunisia, North Africa

The Sicilo-Sarde, the only native milking sheep in Tunisia and in North Africa has undergone a considerably population reduction from 200,000 ewes in 1995 to 25,000 ewes in the year 2000. Low sheep milk price and a shift to dairy cattle were among the reasons for this decline. The main objective of this study was to report on the impact of farmers organization, technology transfer and market on reversing the dramatic decline of this native dairy sheep breed to a promising livestock development model. Having at the grassroots a “pioneer” who chose to form the Sicilo-Sarde breed association in 2003 was a key ingredient in the process of saving this breed from disappearance. Quick steps were first taken: Selling milk through the association allowed doubling its price in one year. A new legislation benefiting dairy sheep was introduced. A trilogy principle was followed where breed owners, researchers and policy makers interacted together to find optimum solutions that fit expressed needs of breed owners. An applied multidisciplinary research program was established and tackled major constraints faced by the breed in nutrition, management, reproduction, health, breeding and product development. Encouraged by an unsatisfied market and good prices, small farmers with a few cows started shifting to dairy sheep and poor new ones managed to get loans to purchase dairy sheep breeding animals. Based on a total of 7937 lactations recorded during the period 1997–2002, average milk yield, days in milk and suckling period were 89 kg ± 47 kg, 139 d ± 47 d and 104 d ± 22 d, respectively. Given the low producing ability of the breed and the impossibility of importing proven rams for health considerations, frozen semen from 17 Sarda rams was imported from Italy and 1600 ewes from 12 flocks were inseminated by intrauterine in 2005–2006. Fertility, prolificacy, and mortality rates varied from 47% to 63%, 157% to 184% and 0 to 34%, respectively. The decline of the breed was stopped and reversed and members of the association and small farmers in the region will benefit from the produced offspring. While currently the association is accessed by more organized producers, it provides an opportunity for the integration of smaller, poorer producers to improve their livelihoods. This case has inspired another group of farmers of a native sheep meat breed to form their own association to promote their breed.

Short Communication: Evaluation of the Overall Accuracy of the DeLaval Cell Counter for Somatic Cell Count in Ovine Milk: Effect of Soak Time in Diluted and Undiluted Milk Samples

This study evaluated the performance of the DeLaval cell counter (DCC) when analyzing ovine milk with different soak times (defined as the permanence time of samples within the DCC cassette before starting the DCC counting procedure) in diluted and undiluted milk samples in 2 dairy sheep breeds. A total of 101 composite ovine milk samples (50 from Assaf ewes and 51 from Churra ewes), ranging between 50×103 and 2,200×103 cells/mL, were divided into 10 aliquots/milk to be analyzed by DCC. Four undiluted aliquots and 4 aliquots diluted 1:1 in PBS were analyzed by using soak times of 0, 1, 2, and 3 min/aliquot, and the other 2 aliquots were diluted 1:1 in propidium iodide or ethidium bromide staining solutions and analyzed by DCC. Milk samples were also analyzed by the Fossomatic method, as a reference. All analyses were carried out in duplicate. Undiluted milk samples with soak times ≥1min showed large coefficients of regression (b=0.96 to 0.98) and correlation (r>0.99) when compared with the Fossomatic method. In these samples, DCC gave repeatability standard deviations (sr=35 to 51×103 cells/mL) lower than other DCC analytical conditions (sr=49 to 74×103 cells/mL), and their log SCC means (5.51 to 5.52) were close to the reference value (5.56). The log SCC means corresponding to samples diluted 1:1 in staining solutions (5.55) did not differ from the reference value; however, these aliquots had lower regression coefficients (b: 0.92 to 0.93). Samples diluted 1:1 in PBS and undiluted samples with a 0-min soak time showed a global accuracy similar to or lower than undiluted samples with soak times ≥1min. Breed did not seem to affect the results. We concluded that undiluted raw milk with a soak time ≥1min and analyzed by DCC shows suitable overall accuracy in ovine milk compared with the reference method and can be considered as the best option for on-farm use from an operational point of view.

Response to Lactation Induction Differs by Season of Year and Breed of Dairy Ewes

Lactation artificially induced (ART) by steroid hormones and natural lactation (NAT) after lambing were compared in 2 dairy sheep breeds (Manchega and Lacaune) in 2 experiments conducted during winter and spring. In experiment 1, ART ewes (14 Manchega and 9 Lacaune) were induced into lactation in winter by the standard protocol, which consisted of s.c. injections of estradiol and progesterone administered in 2 portions daily from d 1 to 7. Hydrocortisone acetate was injected s.c. daily on d 18 to 20. Milking was initiated on d 21 and continued for 13 wk. A similar group of NAT ewes was selected for the contemporary comparison of NAT vs. ART lactation. All Lacaune ewes, but only 3 of the 14 Manchega ewes (21%), were successfully induced into lactation. Despite the successful induction of lactation in Lacaune ewes, milk yield was much lower than that obtained in NAT lactation (1.23±0.14 vs. 2.51±0.15 L/ d). Milk composition from wk 5 to 13 did not differ between groups, except for whey protein, which was greater in ART than in NAT ewes (1.47 vs. 1.25%). In experiment 2, 19 Manchega ewes were divided into 2 groups and induced into lactation in spring by using the standard induction protocol, similar to that used in experiment 1 (control, n=9), or the standard protocol modified with bovine somatotropin (bST, 250 mg/ewe on d 11; n=10). Manchega ewes had an improved response to the standard protocol of lactation induction in spring compared with winter. Milk yield in bST-treated Manchega ewes was 98% greater than that in control ewes (402±85 vs. 203±86 mL/d). The use of bST during mammogenesis did not affect milk composition. In conclusion, marked differences between Manchega and Lacaune dairy ewes were observed in their response to lactation induction when using the standard protocol during different photoperiod conditions. The Manchega ewes were unable to establish lactation in winter but were able to do so in spring. The response to lactation induction in dairy ewes seems to be related to their endogenous levels of prolactin and growth hormone, the use of which should be explored more deeply in future research.

Breeding for resistance to mastitis in United Kingdom sheep, a review and economic appraisal

Mastitis is a problem in the sheep industry, and its incidence varies widely with how it is recorded, the breed of sheep and the farm. Virtually all the published information...

Short Communication: Study of Immune Parameters in Three Greek Dairy Sheep Breeds During the Periparturient Period

The objective of the present study was to evaluate whether immunosuppression occurs in 3 different Greek dairy sheep breeds during the periparturient period. A total of 33 ewes from 3 breeds [i.e., the low-producing Boutsiko breed (n=11), which is highly adaptable to harsh environments; the high-producing but environmentally fragile Chios breed (n=11); and an intermediate synthetic breed (50% Boutsiko, 25% Arta, and 25% Chios, n=11)] were used. Blood samples were collected at 18 and 2 d before parturition and at 15 d after parturition. Total cell-associated and membrane-bound urokinase plasminogen activator (U-PA) activity, free U-PA binding sites on cellular membranes, and superoxide anion (SA) production by activated phagocytes were determined. Results indicated that all immune parameters measured remained constant during the periparturient period for the Boutsiko breed. In contrast, there were reductions in total cell-associated and membrane-bound U-PA activity by both monocytes-macrophages and neutrophils and in SA production by monocytes-macrophages at d 2 before parturition for the Chios breed. In the synthetic breed, there were reductions in total cell-associated and membrane-bound U-PA activity by monocytes-macrophages and in SA production by both monocytes-macrophages and neutrophils at d 15 after parturition. Thus, mild immunosuppression during the periparturient period was observed in the 2 breeds with the highest milk production.

The interaction between breed and diet on CLA and fatty acids content of milk fat of four sheep breeds kept indoors or at grass

An experiment was conducted with the objective to study the interaction between breed and diet on conjugated linoleic acid (CLA) and fatty acids profile (FA) content of milk fat of four pure of dairy sheep breeds (Awassi, Lacaune, Friesland and Chios). All sheep used in this study were kept in one flock under the same management. During the winter months (from October to March) all sheep were kept indoors and fed with alfalfa hay and concentrates without any grazing and from April onwards were grazing native pastures without any supplementary feed. A total of 160 individual milk samples were taken from the four breeds at two sampling times: in January ( n = 80) and in May ( n = 80), when the ewes were in average, on 62 and 185 days in milk. These milk samples were analyzed for FA profile. The results of this experiment showed that the sheep breed had no effect on milk FA profile or on atherogenicity index (AI). The only significant effect was on Δ −9 desaturase activity index expressed as C 18:1/ C 18:0. On the contrary, the diet affected significantly the FA profile of all ewes milk fat, with pasture to cause lower proportions of saturated and higher proportions of unsaturated FA, compared with those of sheep kept and fed indoors. The interaction between breed and diet was significant for the FA C 10:0, C 14:0, C 15:0, C 16:0, C 17:1, C 18:1, C 18:2n6c, C 18:2n6t, C 18:3n6 and CLA and for FA groups SCFA, MCFA, LCFA and MUFA. The S/U FA ratio and the Δ −9 desaturase indexes ( C 14:1/ C 14:0 and C 18:1/ C 18:0) were also affected by the breed × diet interaction. In conclusion, pasture feeding when compared with supplementary diet, induce large variation in the milk FA profile. In addition pasture increases FA in milk fat which has potential interest for human health. Breed has small effect on milk FA profile, but it can be ignored as it is shown from the interaction breed × diet.

Factors Affecting the Plasmin-Plasminogen System in Milk Obtained from Three Greek Dairy Sheep Breeds with Major Differences in Milk Production Capacity

The purpose of this study was to evaluate the effect of breed, stage of lactation, and health status of the udder on the plasmin-plasminogen system in ovine milk. A total of 38 ewes were used from 3 breeds [Boutsiko (n=12), Chios (n=12), and a synthetic breed (50% Boutsiko, 25% Arta, and 25% Chios, n=14)] with major differences in their genetic potential with respect to milk yield. Milk samples were collected every 2 wk throughout the lactation period and were analyzed for fat, protein, lactose, and somatic cell count (SCC). In addition, milk plasmin (PL), plasminogen (PG), and plasminogen activator (PA) activities were determined. The Chios breed had the greatest average daily milk yield, the synthetic breed had an intermediate milk yield, and ewes of the Boutsiko breed had the lowest milk yield. Milk samples obtained from the Boutsiko breed had similar PL and PA activities, compared with those obtained from the other 2 breeds. The ratio of PG:PL was less in milk samples from the Boutsiko breed compared with the other 2 breeds, indicative of an increased rate of conversion of PG to PL for this breed. There was no correlation between PL activity and daily milk yield in ewes from all 3 breeds. Activities of PL, PG, and PA were greater in ovine milk with elevated SCC (>300,000/mL) compared with activities in milk with low SCC (<300,000/mL). The ratio of PG:PL was less in the high-SCC group compared with the low-SCC group, which indicates an increased rate of conversion of PG to PL for the high-SCC group. There was a decrease in PG and PA activities as well as in the PG:PL ratio in late lactation milk (mo 5 to 6) when compared with early or mid lactation milk (mo 1 to 4). Thus, the PL-PG system is affected by breed, stage of lactation, and the health status of the udder. No relationship was found between PL activity and daily milk yield in the 3 Greek dairy sheep breeds. Plasmin is not a marker for gradual involution in the Greek sheep breeds studied.

Differences in susceptibility toMannheimia haemolytica-associated mastitis between two breeds of dairy sheep

We used a Mannheimia haemolytica isolate to study differences in susceptibility to experimental mastitis between two breeds of dairy sheep. The isolate was deposited into the teat duct of Karagouniko (K, n=8) or Frisarta (F, n=8) ewes. The animals were monitored by means of clinical, bacteriological, cytological and pathological methods. K ewes did not develop any systemic or mammary clinical signs, whilst F ewes became ill and developed acute clinical mastitis 12 h later (P<0.001). Bacteria were isolated from 34/48 samples from K ewes and from 46/46 samples from F ewes. Positive California mastitis test (CMT) results were 17/24 samples from K ewes and 23/23 samples from F ewes; leucocytes were seen in Giemsa-stained films. Total pathology score summed over all group K ewes was 41 (maximum possible: 128); Man. haemolytica was isolated from 12/24 tissue samples. Total pathology score summed over all group F ewes was 93; Man. haemolytica was isolated from 24/24 tissue samples. Hyperplastic lymphoid nodules consisting of lymphocytes and plasma cells with germinal activity were characteristically present at the border between teat duct-teat cistern of group K ewes; no such structures were observed in teats of group F ewes. The results identified differences in susceptibility/resistance to a mastitis pathogen among animals of the two breeds. Defence mechanisms of the teat appeared to be inadequate against the invading organisms; as lymphoid nodules have been considered important defensive mechanisms of the ovine teat, their observed lack in Frisarta ewes might have predisposed them to development of mastitis.

Economic weights of somatic cell score in dairy sheep

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 − 2.6 to − 9.5 € per point of SCS, with an average of − 4 € 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 € per l of milk yield and − 4 € per point of SCS, assuming a genetic correlation of − 0.30, were 3.85 l and − 0.031 SCS per year, with an associated increase in profit of 3.32 €. 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.

Basic and incentive payments for goat and sheep milk in relation to quality

Dairy sheep and dairy goat breeding in Europe is most common around the Mediterranean basin, particularly in France, Greece, Italy and Spain. Over recent years the tendency has been a slight reduction in the number of animals bred, while at the same time there has been a general increase in the volume of milk produced. The milk of sheep and goats is mainly reserved for cheese making and therefore a quality evaluation of the milk is of fundamental importance. If, on the one hand, the achievement of a certain level of quality is of interest for the cheese making industry, which has to deal with the ever-increasing demands of the consumer, it is also of interest to the milk producers, who can increase their earnings by pursuing high quality. The quality of the milk for cheese making depends essentially on its physical and chemical composition and on hygienic and sanitary factors (bacterial count, somatic cells count, etc.). The price of sheep and goat milk is generally higher than that of cow milk, even though in certain areas of production it is not specifically exploited, being blended with cow milk for the production of mixed cheeses. Differentiated pricing in relation to quality is becoming ever more widespread also for sheep and goat milk. This is mainly based on the construction of a grid on which various parameters are taken into consideration in order to establish bonuses and penalties, which are then applied to the base price of the milk. This paper summarises some previous works on this subject and integrates them with the new scenarios, while at the same time discussing how to improve the quality and subsequently the valorisation of these milks.

Identification of a new leucine haplotype (ALQ) at codon 154 in the ovine prion protein gene in Spanish sheep1

Genetic susceptibility to scrapie is closely linked to variations at codons 136, 154, and 171 of the prion protein (PRNP) gene. This association between the PRNP genotype and susceptibility to scrapie is the basis of breeding programs for scrapie resistance in different countries. In this paper, we describe the method used with 2 Spanish dairy sheep breeds (Churra and Castellana) to ascertain the initial status of protection against scrapie as a first step toward adapting their breeding schemes to include resistance as a complementary selection criterion. The procedure for genotype identification is based on multiplex minisequencing methodology and has been shown to be accurate, easy to interpret, and to have a medium throughput. The frequency of the ARQ allele was similar in the 2 populations at nearly 70%. The ARR allele, associated with resistance in the homozygous state, reaches around 23% in Churras and nearly 20% in Castellanas. The high-risk VRQ allele appeared at a relatively low frequency in both breeds. No other haplotypes were found in these 2 breeds. Furthermore, in this screening we found a new allele carrying leucine at codon 154. This new genetic variant might play a role in susceptibility to scrapie because codon 154 belongs to a region considered to have an important role in conformational conversion of the cellular to the pathogenic protein.

Le programme français d’éradication de la tremblante du cheptel ovin fondé sur l’utilisation de la génétique

Les travaux conduits en ovins laitiers dès 1993 dans des élevages ovins atteints de tremblante ont permis de connaître la fréquence des allèles sensibles du gène PrP selon les races considérées, vérifier le risque accru de tremblante pour ces génotypes, et tester la faisabilité d’une sélection sur le gène PrP et son efficacité sur le risque de tremblante dans les troupeaux. Ils ont ainsi contribué à l’émergence de l’outil génétique pour éradiquer la tremblante dans les élevages atteints. Depuis 2002, le programme d’éradication de la tremblante mis en place en France par le Ministère de l’Agriculture, est fondé sur le génotypage du gène PrP : il vise à éradiquer à court et moyen terme la tremblante dans les élevages atteints, tout en renforçant la résistance génétique à moyen et long terme de l’ensemble du cheptel national, compte tenu des délais de renouvellement des cheptels femelles. Avoir choisi d’asseoir le programme national de sélection sur le dispositif existant d’amélioration génétique du cheptel national, organisé dans le cadre de la loi de l’Elevage de 1966, est manifestement un point clé pour expliquer la mise en oeuvre rapide et efficace du programme dès la première année, confirmant la mobilisation massive de tous les maîtres d’oeuvre des schémas de sélection des ovins en France : les évolutions conjointes constatées pour les fréquences alléliques en faveur de l’allèle ARR, les index de sélection pour les caractères de production et les indicateurs de gestion de la variabilité génétique sont une bonne illustration de l’application des objectifs assignés aux programmes de sélection. L’encadrement national, conduit par l’INRA, l’Institut de l’Elevage et France UPRa Sélection (Unité de Promotion et de sélection de Race), s’attachera, dans les prochaines années, à vérifier et à aider à la mise en oeuvre des quatre objectifs du programme national de sélection, en particulier la fourniture de reproducteurs résistants pour les élevages atteints, la gestion de la variabilité génétique dans les noyaux de sélection et la diffusion vers les élevages de production. Ce programme repose sur les points clés d’universalité de la résistance génétique à la tremblante en situation de contamination naturelle et d’absence de porteurs sains, qu’il faudra en permanence continuer de valider.

Breeding and animal welfare: practical and theoretical advantages of multi-trait selection

AbstractThe traditional concerns about farm animal welfare have centred around the impact of intensive environments and management practices on the animal. This emphasis on the physical environment is changing, however, with greater consideration being given to animal factors and in particular to the selective breeding of farm animals. In this paper we use examples from our own research on dairy cattle and sheep breeding that have made positive and practical contributions towards reducing welfare problems by creating more balanced breeding programmes. In both examples, inclusion of health and fitness traits into breeding indexes can be shown to be more profitable than selecting on production traits alone. In addition, we propose that in principle animal breeding combined with economics research can make a more general contribution towards resolving animal welfare issues, by providing a framework for the quantitative evaluation of the costs and benefits of an animal production system. The advantage of the approaches currently used in multi-trait selection is that they transform all traits (production-based or welfare-based) to a common currency allowing direct comparisons of costs and benefits. Currently the weights applied to traits reflect their economic value to the producer. This approach is likely to underestimate non-economic welfare aspects such as the pain or discomfort associated with lameness, and new approaches are needed to more fully account for these non-economic welfare costs. We therefore propose that consideration is given to the use of approaches such as contingent valuation, which has been widely used in economics to derive values for non-economic activities. The question of who would pay for the addition of these welfare costs to a breeding index remains open, but it would seem most reasonable to treat these as a public good and pay for them as such through appropriate mechanisms.

Effects of feeding ensiled sliced oranges to lactating dairy sheep

Ninety six lactating ewes of the Sfakian dairy sheep breed, divided into two equal groups were used. Three kilograms (79.5%) sliced orange silage mixture with by-products were offered daily to the animals as experimental treatment, replacing part of the maize grain/soybean meal/oat hay ration given to the controls. Microbiological and chemical analyses of silage showed that ensiling high moisture materials such as whole oranges is feasible. Silage pH from 4.1 before, dropped to 3.7 after ensiling. Colony forming units of yeasts and fungi in silage were approximately 200-fold lower at the end of the ensiling process. Silage DM was 16% lower at the end of ensiling (25.0 versus 21.0%). Orange silage mixture composition was CP 13.4, crude fibre 13.4, fat 2.3, ash 7.93, Ca 0.99 and P 0.7% on DM basis and proved palatable to sheep particularly due to its pleasant odour. Milk yield and composition were measured for a 6-week period. Overall daily milk yield was 12% higher for controls (769.0±28.9 g versus 680.0±21.0 g, P<0.05) but the situation was reversed for the last third of the lactation period. However, 6% fat corrected milk yields (821.0±31.8 versus 832.0±28.5) did not differ significantly. Ewes fed orange silage had 16% higher fat content in milk ( P<0.05). Treatment differences in ewes’ body weight were not significant during the experimental period. Results show that the inclusion of ensiled sliced oranges to diets of lactating sheep is a viable proposition.

Effect of production systems on carcass quality characteristics of lambs

Our objective was to provide basic information that can be used to direct sheep production to produce meat, which meets consumer demands. Here, we present the results of a series of studies that were designed to assess the effect of different production systems on carcass quality characteristics of lambs from Greek dairy breeds of sheep.