Genetic modelling of test day records in dairy sheep using orthogonal Legendre polynomials

Kominakis, A.; Volanis, M; Rogdakis, E.

doi:10.1016/s0921-4488(00)00191-7

Cited by 22 publications

(25 citation statements)

References 17 publications

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“…As presented on Table 1, mean DMY of extensive farms was close to the levels previously recorded for Sfakia breed (0,7l mean DMY; Kominakis et al, 2001). However, mean DMY of semi-intensive farms exceeded the expected levels.…”

Section: Discussionsupporting

confidence: 79%

“…It is a hardy small sized breed (weight: 44kg -64kg; height: 64cm -74cm, for ewes-rams, respectively) with relatively high milk production of 109.8±40.8l of milk for a lactation period of 156.5±29.3 days (Kominakis et al, 2001). Mating period is in May and June (for multiparous ewes) or at the end of summer (for less than one year old -primiparous-ewes).…”

Section: Selection Of a Study Area And A "Low-input Sheep Breed"mentioning

confidence: 99%

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Effect of management factors on reproductive and milk production performance of a dairy sheep breed adapted to low-input management systems

Tzanidakis

Voutzourakis

Stefanakis

et al. 2018

J Hellenic Vet Med Soc

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Interest on the implementation and improvisation of low-input dairy sheep farming is rising. Our study aimed to describe a) the milk productivity of the Sfakia sheep, a Mediterranean well-adapted to low-input management schemes breed (“low-input breed”), and b) the effect of management (MS) and milking system (MLS) on milk yield and quality. Monthly bulk milk samples (n=307) and reproductive data were collected from 10 extensive and 10 semi-intensive Sfakia sheep flocks in Crete Greece, over two consecutive lactations. All semi-intensive and four extensive farms were equipped with a milking parlour machine (MPM). A portable machine (PM) was used in three extensive farms; hand-milking (HM) was applied in the rest extensive farms. The effect of MS and MLS on daily milk yield/ewe (DMY), somatic cell count (SCC), total bacterial count (TBC), pH and % lactose content (LACT) of milk was explored with linear mixed-effects models. Mean DMY (p<0.001) as well as the seasonal variation pattern of SCC (p=0.020) and LACT (p=0.018) differed between MS. TBC was higher in extensive farms using MPM than HM (p=0.002); PM was related to lower SCC, compared to MPM (p=0.044) and HM (p=0.012). Concluding, mild interventions in management and milking practices could improve the productivity of “low-input” dairy sheep breeds.

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Section: Discussionsupporting

confidence: 79%

Section: Selection Of a Study Area And A "Low-input Sheep Breed"mentioning

confidence: 99%

Effect of management factors on reproductive and milk production performance of a dairy sheep breed adapted to low-input management systems

Tzanidakis

Voutzourakis

Stefanakis

et al. 2018

J Hellenic Vet Med Soc

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“…Contrariwise, small differences (only 4% for both breeds) observed when daily milk yields of Tsigai and Improved Valachian ewes were compared with previous analyses based on the test-day approach (Oravcová et al, 2005) indicate that the phenotype selection of the last years (since 2000) was not reflected in higher milk yields. Average daily milk yield of Tsigai and Improved Valachian breeds was much lower than daily milk yield of dairy breeds like East Friesian (Hamann et al, 2004), Assaf (Pollot and Gootwine, 2004), Churra Gonzalo et al, 1994;El-Saied et al, 1998;Fuertes et al, 1998), and also Bovec, Istrian Pramenka (Komprej et al, 2003), Black-Faced and Blond-Faced Latxa (Gabina et al, 1993), and Sfakia (Kominakis et al, 2001). On the contrary, it was higher in comparison with Florina (Christodoulou et al, 1997) and Cine Type sheep (Karaca et al, 2000) classified as multipurpose breeds.…”

Section: Resultsmentioning

confidence: 91%

Factors affecting milk yield and ewe's lactation curves estimated with test-day models

Oravcová¹,

Margetín²,

Peškovičová³

et al. 2006

Czech J. Anim. Sci.

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Test-day records of purebred Tsigai, Improved Valachian and Lacaune ewes were analysed with a general linear model in order to investigate the effects of flock-test day, lactation number, days in milk, litter size and month of lambing. In total, 121 576 (Tsigai), 247 902 (Improved Valachian) and 2 196 (Lacaune) test-day records gathered over the period [1995][1996][1997][1998][1999][2000][2001][2002][2003][2004][2005] were included in the analyses. Average daily milk yields were 0.604 ± 0.279 kg (Tsigai), 0.595 ± 0.243 kg (Improved Valachian) and 1.053 ± 0.475 kg (Lacaune). The significant (P < 0.05) or highly significant (P < 0.01) effects of flock-test day, lactation number (except for Lacaune), days in milk, litter size (except for Lacaune) and month of lambing (either fixed effects or covariates) tested by Fisher's tests were shown. The model explained about 50% of daily milk yield variability, with coefficients of determination as follows: 0.479 for Improved Valachian; 0.487 for Tsigai; 0.537 for Lacaune. Differences in estimated least-squares means were tested using multiple-range Scheffe's tests. A lower daily milk yield was found for the first lactation, single litter and lactations starting in March in comparison with daily milk yield for the second and third lactations (except for Lacaune), multiple litter and lactations starting in January and February (except for Improved Valachian). AliSchaeffer regression adopted for sheep was used for the fitting of lactation curve according to breed.

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“…As seen from the literature, most authors treated only the additive genetic effect in the random part of the model in dairy cattle (Danell, 1982, Wilmink, 1987, Meyer et al, 1989 as well as in dairy sheep (Baro et al, 1994, Serrano et al, 2001, Volanis et al, 2002. Some of them (Swalve, 1995, Kominakis et al, 2001, Ilatsia et al, 2006, Tonhati et al, 2008 included the permanent environment effect over lactations in the random part as we did. Besides additive genetic effect, Andonov et al (1998) took into account flock-test-month effect in the random part of the model for (co)variance estimation in Slovenian dairy goats.…”

Section: Phenotypic Variancementioning

confidence: 99%

Genetic and environmental dispersion parameter estimationby test interval method in dairy sheep

Komprej¹,

Kompan²,

Kovač³

2011

Acta Agriculturae Slovenica

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Genetic modelling of test day records in dairy sheep using orthogonal Legendre polynomials

Cited by 22 publications

References 17 publications

Effect of management factors on reproductive and milk production performance of a dairy sheep breed adapted to low-input management systems

Effect of management factors on reproductive and milk production performance of a dairy sheep breed adapted to low-input management systems

Factors affecting milk yield and ewe's lactation curves estimated with test-day models

Genetic and environmental dispersion parameter estimationby test interval method in dairy sheep

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