Correlações genéticas entre algumas características de tipo e intervalo de partos em vacas da raça Holandesa

Silva, R.P.A.; Neto, André Thaler; Cobuci, Jaime Araújo; Valloto, Altair Antônio; Horst, José Augusto; Neto, P. G. Ribas

doi:10.1590/1678-6445

Cited by 3 publications

(1 citation statement)

References 21 publications

(11 reference statements)

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“…A possible explanation for the unfavorable genetic correlations between the mammary traits with calving interval is due to the fact that selection for increased milk production, for long years (which is unfavorably correlated to fertility), has resulted in unfavorable genetic trends in fertility, as the increase in calving interval (Veerkamp et al, 2001;Wall et al, 2005). Silva et al (2015) also reported similar results for genetic association between foot angle, chest width, rump angle, body depth with calving interval. However, these authors and Makgahlela et al (2009), indicate that selection for rump width can improve the calving interval in dairy cows, which differs from our study and from the Wall et al (2005) study, in which no genetic association was found between these two traits.…”

Section: Resultsmentioning

confidence: 76%

Genetic associations between reproductive and linear-type traits of Holstein cows in Brazil

et al. 2017

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-This study aimed to estimate heritability, genetic, and residual correlations between reproductive traits such as age at first calving, calving interval, dry period, and first service period and linear type traits measured in Holstein cows born between the years 1990 and 2008 in Brazil. The (co)variance components were estimated by restricted maximum likelihood, using the MTDFREML software. The heritability for reproductive traits and linear-type traits ranged from 0.02 to 0.03 and from 0.07 to 0.40, respectively. Estimates of genetic correlations between reproductive and linear-type traits ranged from -0.23 (top line) to 0.28 (angularity) to age at first calving, from -0.54 (final score) to 0.34 (foot angle) to calving interval, from -0.23 (angularity) to 0.56 (stature) to dry period, and from -0.52 (final score) to 0.36 (height udder) to first service period. Direct selection for any of the reproductive traits implies low genetic gains by virtue of their low heritabilities. Among the linear-type traits, the final score, chest width, top line, angularity, teat length, udder attachment, rear teat placement were highlighted as good auxiliary traits to improve reproductive efficiency of Holstein cows in Brazil. The simultaneous selection for reproductive and linear-type traits can lead a higher genetic progress in the reproductive traits.Key Words: age at first calving, dairy cattle, genetic parameters, reproductive efficiency Revista Brasileira de Zootecnia

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Section: Resultsmentioning

confidence: 76%

Genetic associations between reproductive and linear-type traits of Holstein cows in Brazil

et al. 2017

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Proportional hazard models associated with the survival of dairy goats reared in a tropical environment

Ferreira

Martins

Gouveia

et al. 2020

Small Ruminant Research

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Longitudinal retrospective study on the effect of season on milk production and composition in Rio Grande do Sul, Brazil

Sicheski

Haygert-Velho

Piuco³

et al. 2020

SCA

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This longitudinal retrospective study evaluated production and composition of milk from dairy cows according to season on a rural property in Palmeira das Missões, Rio Grande do Sul, Brazil, between January 2009 and December 2016. Milk yield per hectare per month was the primary variable measured, along with chemical composition (total dry extract, defatted dry extract, fat, protein, and lactose), somatic cell count, and total bacterial count of milk. Production in summer (513.53 kg/ha/month) did not differ (p > 0.05) from that in fall (504.69 kg/ha/month) or spring (564.63 kg/ha/month), but production in winter (639.20 kg/ha/month) was significantly higher than in summer (p < 0.0057). The real price of milk did not differ (p > 0.05) among seasons. The total dry extract content differed (p < 0.0059) between seasons. However, the cooler fall and winter seasons favored the production of total solids. The defatted dry extract content was higher (p < 0.0001) in winter (8.65%), compared to the other seasons of the year. Fat content did not differ (p > 0.05) among seasons. Protein content differed (p < 0.0200) between summer (3.01%) and winter (3.16%), but both seasons did not differ (p > 0.05) from fall (3.13%) or spring (3.05%). Winter lactose levels (4.52%) were higher (p < 0.0011) than during other seasons. The somatic cell count did not differ (p > 0.05) among seasons, demonstrating that the evaluated herd possesses standard mammary gland health. The total bacterial count did not differ (p > 0.05) among the seasons, demonstrating that the hygiene of the facilities remains constant. As expected, the temperature and humidity index varied (p < 0.0001) with the seasons, and the deleterious effects were more pronounced in summer and spring, as they are the hottest seasons in humid subtropical environments. The results emphasize that the organized management of milk production reduces the variation in milk composition, making it easier to maintain a consistent high milk quality and also generating extra revenue.

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Correlações genéticas entre algumas características de tipo e intervalo de partos em vacas da raça Holandesa

Cited by 3 publications

References 21 publications

Genetic associations between reproductive and linear-type traits of Holstein cows in Brazil

Genetic associations between reproductive and linear-type traits of Holstein cows in Brazil

Proportional hazard models associated with the survival of dairy goats reared in a tropical environment

Longitudinal retrospective study on the effect of season on milk production and composition in Rio Grande do Sul, Brazil

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