Genetic parameters for milk yield and litter size in Boutsico dairy sheep

Kominakis, A.; Rogdakis, E.; Koutsotolis, K.

doi:10.4141/a98-049

Cited by 25 publications

(14 citation statements)

References 32 publications

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“…In Spanish Merino sheep, estimates of r m between weight at 30, 60, and 90 d and litter size ranged from −.05 to .03 (Analla and Serradilla, 1998). Kominakis et al (1998) reported an estimate of the additive direct correlation between litter size and actual milk yield of .13 in Boutsico dairy sheep.…”

Section: Discussionmentioning

confidence: 99%

“…More recently, Al-Shorepy and Notter (1996) reported h 2 estimates for litter size in fall and in combined fall and spring lambings of .10 and .05, respectively. Altarriba et al (1998) obtained an estimate of h 2 for litter size of .077 ± .017 in Rasa Aragonesa sheep using a threshold model, and Kominakis et al (1998) reported an estimate of h 2 for litter size of .06 ± .03 for Boutsico dairy sheep in Greece.…”

Section: Discussionmentioning

confidence: 99%

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Genetic analysis of litter size in Targhee, Suffolk, and Polypay sheep.

Rao

Notter

2000

Journal of Animal Science

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Data on litter size, weaning weights at 60, 90, and 120 d, postweaning gains from weaning to 120 or 365 d of age, fleece weight, and fiber diameter from Targhee, Suffolk, and Polypay flocks participating in the U.S. National Sheep Improvement Program were used to estimate genetic parameters for litter size and genetic relationships between early-life traits and future litter size. Records on 7,591 lambings by 3,131 Targhee ewes, 10,295 lambings by 5,038 Suffolk ewes, and 6,061 lambings by 2,709 Polypay ewes were used. Heritability estimates for litter size ranged from .09 to .11 across breeds; repeatability ranged from .09 to .13. Additive genetic effects on litter size were generally positively, and occasionally significantly, correlated with animal additive genetic effects on weaning weights and postweaning gains. Genetic correlations (r(a)) ranged from .08 to .48 in Targhee and from .17 to .43 in Suffolk but were close to 0 in Polypay (-.14 to .09). Additive maternal effects on weaning weight were positively associated with litter size in Suffolk and Polypay; this correlation was negative (-.23 to -.35), but not significant, in Targhee. Fleece weight was not strongly associated with litter size; (r(a) = -.09 to .21). However, fiber diameter had a significant undesirable correlation with litter size (.30) in Targhee. Estimates of phenotypic correlations of litter size with early-life traits were uniformly small (-.02 to .08). Thus, although occasional genetic antagonisms between litter size and early-life traits were observed in these data, none appeared large enough to prevent simultaneous genetic improvement in both traits.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Genetic analysis of litter size in Targhee, Suffolk, and Polypay sheep.

Rao

Notter

2000

Journal of Animal Science

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“…Two typical indigenous breeds, Chios and Boutsiko, along with a synthetic breed were used in this study. The Chios breed is characterized by high milk yield and litter size, whereas the lessproductive Boutsiko breed is known for its adaptability under harsh environmental conditions and its reduced susceptibility to mastitis (Hatziminaoglou et al, 1990;Simos et al, 1996;Kominakis et al, 1998;Ploumi et al, 1998). The synthetic breed (50% Boutsiko, 25% Arta, and 25% Chios) has been recently formed in an attempt to upgrade the Boutsiko breed by combining the high productivity of the Chios and Arta breeds with the robustness of the Boutsiko breed.…”

Section: Introductionmentioning

confidence: 99%

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

Θεοδώρου

Kominakis

Rogdakis

et al. 2007

Journal of Dairy Science

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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.

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“…Boutsko, Sfakia and Lesvos). These studies showed that improvement of important traits was possible through selection (Kominakis et al, 1998;Ligda et al, 2000;Mavrogenis and Papachristoforou, 2000;Kominakis et al, 2002;Ligda et al, 2003;Nikolaou et al, 2004). Milk yield and composition were found to be antagonistically correlated indicating that selection for one trait would adversely affect the other (Volanis et al, 2002).…”

Section: Dairy-related Traitsmentioning

confidence: 99%

Genetic improvement of indigenous Greek sheep and goat breeds

Argyriadou¹,

Gelasakis²,

Banos³

et al. 2020

J Hellenic Vet Med Soc

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The objective of the study was twofold: (i) to review the genetics of production and resilience traits of indigenous Greek small ruminant breeds as well as the evolution of national breeding programs, and (ii) explore innovative and feasible approaches to overcome the challenges and constraints towards improving these breeds and enhancing the sustainability of the small ruminant sector. Previous studies on the genetic basis of production and resilience traits of indigenous breeds revealed high improvement potential. However, the lack of follow-up action has failed to produce applicable results. Thus, implementation of scientific findings in existing breeding programs for these breeds is extremely limited. The latter has contributed to the overall poor success of such programs. Furthermore, due to the fact that most farmers do not comprehend the strategic importance of genetic improvement and lack motivation for self-funding, breeding programs have mostly relied on European or government funding; the latter has resulted in intermittent implementation. Therefore, most programs failed to improve performance of indigenous Greek breeds, many of which were consequently replaced by foreign breeds of higher productivity and documented merit. In order to facilitate the design of breeding schemes and overcome the challenges towards improvement of indigenous breeds, an integrative approach is necessary. The latter should be based on identification of specific breeding objectives, reflecting the priorities and needs of the sector, as well as the capacity of the indigenous populations. Scientific advances exemplified by genomic selection and novel reproductive technologies will enable faster and more effective genetic improvement. The overall approach is expected to enhance the competitiveness of indigenous Greek small ruminant breeds and the sustainability of the sector.

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Genetic parameters for milk yield and litter size in Boutsico dairy sheep

Cited by 25 publications

References 32 publications

Genetic analysis of litter size in Targhee, Suffolk, and Polypay sheep.

Genetic analysis of litter size in Targhee, Suffolk, and Polypay sheep.

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

Genetic improvement of indigenous Greek sheep and goat breeds

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