Influ?ncia do manejo de aleitamento e do grupo gen?tico no desempenho de vacas leiteiras mesti?as holand?s-guzer? e de suas crias

• Autor(a) principal: Silva, Rosiane Martins da
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRRJ
• Texto Completo: https://tede.ufrrj.br/jspui/handle/jspui/3038
• topic: Cruzamento; Holand?s; Guzer?; Zebu; Crossbreeding; Holstein; Zootecnia

With the aim of evaluating the effect of genetic group and lactation management on the productive and reproductive performance of cows and the development of their calves, an archived data set was extracted and analysed from herd production reports from dairy cows in the Santa M?nica experimental field of EMBRAPA-CNPGL, located in Valen?a municipality, Rio de Janeiro. The herd consisted of 63 multiparous crossbred cows (Red and white Holstein x Guzer? zebu) belonging to five genetic groups, Pure by Cross Holstein (PC, n=10);7/8 Holstein-Guzer? (7/8 HG, n=16); 3/4 Holstein-Guzer? (3/4 HG, n=8); 1/2 Holstein-Guzer? (1/2 HG, n=15); 1/4 Holstein-Guzer? (1/4 HG, n=14). The calving period of the cows was concentrated between May 1983 and August 1985, totalling 114 calves (56 males and 58 females). Lactation management methods used were the milking of cows and non-suckling by calves (CL1), the milking of cows and residual suckling by calves (CL2) and the milking of cows and one-teat suckling by calves in a rotational system (CL3). The total milk production by milking (TMPM), corrected for 305 days; total milk production by milking and suckling (TMP), corrected for 305 days; mean milk production by milking (MMPM), uncorrected; mean daily consumption of milk by calves (MDCC), uncorrected; mean daily milk production by milking and suckling (MDMP), uncorrected; calving interval (CI); milk productions corrected by calving interval (TMP/CI and MMP/CI); calf birth weight (BW); weaning weight (WW) and mean daily weight gain of calves (MDWG) were evaluated. Using the results, it was possible to perceive that the milk production was significantly influenced by the different genetic groups (P < 0,05). In TMPM, TMP and MMPM it was possible to observe that 1/4 HG animals produced less milk than the other four genetic groups. In MDMP, the 1/2 HG animals produced more milk. There was an effect of lactation management on milk production (P < 0,05). Increased milk productions were observed in the CL1 lactation management. Calving interval, TMP/CI and MMP/CI were significantly affected by the genetic group (P < 0,05). Lower CI was observed in 1/2 HG animals. 1/2 HG cows showed higher TMP/CI and MMP/CI means. There was an interaction between genetic group and lactation management on the milk consumption of calves (P < 0,05). Calves subjected to CL3 lactation management consumed more milk than calves subjected to CL1 and CL2. 1/4 HG calves consumed less milk than calves from the other four genetic groups. The crossbreeding promoted significant alterations in BW (P < 0,01), WW (P < 0,05) and MDWG (P < 0,05) of calves. Calves from 1/2, 3/4 and 7/8 HG calves were born heavier than calves from. 1/4 HG and PC cows. Higher WW was also observed in calves from 1/2, 3/4 and 7/8 HG cows. Greater MDWG was observed in calves from 1/2 and 3/4 HG cows. Under the conditions in which the present study was made, genetic group and lactation management were perceived to influence productive and reproductive performance of Holstein-Guzer? cows, as well as the performance of their calves