&lt;b&gt;Estimation of genetic and phenotypic trends for dairy traits of Gyr and Guzerá breeds

Rangel, Adriano Henrique do Nascimento; Araújo, Thalita Polyana Monteiro; Lima, Guilherme Ferreira da Costa; Borba, Luís Henrique Fernandes; Peixoto, Maria Gabriela Campolina Diniz; Júnior, Dorgival Morais de Lima

doi:10.4025/actascianimsci.v40i0.36685

Cited by 3 publications

(1 citation statement)

References 6 publications

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“…The regression coe cient of milk, fat, and protein performance on calving year was 114.38, 2.89, and 3.07, respectively. These values were 88.71, 1.08, and 4.11 Kg for the Gyr breed from 1985 to 2008 (Rangel et al 2017). The level of trends for phenotypic and genetic values is dependent on the selection progress applied to populations over the years.…”

Section: Genetic and Phenotypic Trendsmentioning

confidence: 87%

Estimation of genetic parameters of the productive and reproductive traits in Iranian Holstein cattle using single and repeated records

Tohidi

Nazari²

2023

Preprint

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This study estimated the genetic parameters of productive and reproductive traits of Iranian Holstein cattle from data recorded between 2006 to 2018. The data analysis was performed using an animal model, including the record of the first parity and the first three lactation records. Heritability values for milk, fat, and protein traits using a single record animal model were 0.29 ± 0.005, 0.22 ± 0.005, and 0.24 ± 0.005, respectively. The heritability of these traits based on a repeated records animal model was estimated to be 0.19 ± 0.001, 0.15 ± 0.005, and 0.17 ± 0.006, respectively. Furthermore, the heritability of age at first calving (AFC) and length of lactation (LL) traits were 0.16 ± 0.004 and 0.02 ± 0.002, respectively. Estimated repeatability for milk, fat, and protein production was 0.38 ± 0.002, 0.34 ± 0.002, and 0.36 ± 0.002, respectively. Positive genetic changes occurred over the years of the study for production traits. Evaluation of the effect of herd-year-season (HYS) on the productive traits revealed that the management and environmental conditions improved. The average estimate of heritability for milk, fat, and protein yields and AFC indicates the possibility of genetic improvement for these traits. Furthermore, the repeatability values show that the selection process can be performed based on the first lactation record. The positive genetic trend of productive traits validates the positive response to selection in Iranian Holstein cattle. Consequently, improving environmental and management conditions in Iranian dairy cattle herds is recommended, which will positively affect reproductive traits.

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Section: Genetic and Phenotypic Trendsmentioning

confidence: 87%

Estimation of genetic parameters of the productive and reproductive traits in Iranian Holstein cattle using single and repeated records

Tohidi

Nazari²

2023

Preprint

View full text Add to dashboard Cite

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Estimation of genetic parameters of the productive and reproductive traits in Iranian Holstein cattle using single and repeated records

Tohidi,

Nazari

2023

Trop Anim Health Prod

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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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<b>Estimation of genetic and phenotypic trends for dairy traits of Gyr and Guzerá breeds

Cited by 3 publications

References 6 publications

Estimation of genetic parameters of the productive and reproductive traits in Iranian Holstein cattle using single and repeated records

Estimation of genetic parameters of the productive and reproductive traits in Iranian Holstein cattle using single and repeated records

Estimation of genetic parameters of the productive and reproductive traits in Iranian Holstein cattle using single and repeated records

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

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