Data from a selection experiment for growth carried out in Brazil were analyzed in order to evaluate the direct responses on yearling weight (YW) and the correlated responses on the size and reproduction traits of cows. The experiment was started in 1976, and in 1980 three lines of Nelore cattle were established: selection (NeS), traditional (NeT), both selected for higher YW, and control (NeC), selected for mean YW. The NeT was an open line that eventually received bulls from other herds. Yearling weight records for animals born from 1978 to 1998 and yearling hip height (H550) offemales born from 1985 to 1998 were analyzed by fitting an animal model in order to obtain the genetic trends. The means for weight, height, and body condition score at the start of the breeding season, days to calving, and calving success of cows born from 1993 to 1996 (pertaining to the third to fourth generations of selection) were compared between the selected (NeS and NeT) and control lines. The genetic trends obtained after 16 yr for YW were 1.7 +/- 0.2, 2.3 +/- 0.2, and -0.1 +/- 0.1 kg/yr for males and 1.9 +/- 0.2, 2.4 +/- 0.2, and -0.1 +/- 0.1 kg/yr for females, for the NeS, NeT, and NeC lines, respectively. Corresponding values for H550 were 0.25 +/- 0.03, 0.24 +/- 0.04 and -0.04 +/- 0.03 cm/yr for females. Heifers and cows from NeS and NeT were 19% and 15% heavier and 4% taller at the start of the breeding season than those from NeC. No significant differences between selected (NeS and NeT) and control females were detected for body condition scores and for reproductive performance. The results indicate that selection for body weight promoted high and consistent weight and height responses both at the yearling and later ages, without compromising the reproductive performance of the cows with respect to days to calving and calving success.

-Data comprising 263,390 test-day (TD) records of 32,448 first parity cows calving in 467 herds between 1991 and 2001 from the Brazilian Holstein Association were used to estimate genetic and permanent environmental variance components in a random regression animal model using Legendre polynomials (LP) of order three to five by REML. Residual variance was assumed to be constant in all or in some classes of lactation periods for each LP. Estimates of genetic and permanent environmental variances did not show any trend due to the increase in the LP order. Residual variance decreased as the order of LP increased when it was assumed constant, and it was highest at the beginning of lactation and relatively constant in mid lactation when assumed to vary between classes. The range for the estimates of heritability (0.27 -0.42) was similar for all models and was higher in mid lactation. There were only slight differences between the models in both genetic and permanent environmental correlations. Genetic correlations decreased for near unity between adjacent days to values as low as 0.24 between early and late lactation. A five parameter LP to model both genetic and permanent environmental effects and assuming a homogeneous residual variance would be a parsimonious option to fit TD yields of Holstein cows in Brazil. foi assumida como constante em todo ou em algumas classes do período de lactação para cada PL. As estimativas dos efeitos genético e permanente de ambiente não apresentaram qualquer tendência atribuída ao aumento da ordem do PL. A variância residual diminuiu com o aumento da ordem do PL quando assumida como constante e foi maior no início da lactação e relativamente constante na fase intermediária quando assumida como heterogênea entre classes do período de lactação. As estimativas de herdabilidade variaram de 0,27 a 0,42 em todos os modelos e foram maiores na fase intermediária da lactação.As diferenças entre modelos para as correlações genéticas e de ambiente permanente foram pequenas. As correlações genéticas decresceram de valores próximos à unidade entre as produções de leite de controles próximos para 0,24 entre as produções de leite dos controles do início e do final da lactação. O polinômio de Legendre de cinco parâmetros para a modelagem dos efeitos genético e de ambiente permanente com homogeneidade de variância residual é uma opção parcimoniosa para o ajuste das PC de vacas da raça Holandesa no Brasil.Palavras-chave: avaliação genética, bovinos de leite, componentes de co-variância, herdabilidade, seleção

The genotypes for k-casein (<FONT FACE="Symbol">k</FONT>-CN), <FONT FACE="Symbol">b</FONT>-lactoglobulin (<FONT FACE="Symbol">b</FONT>-LG) and growth hormone (GH) were determined by polymerase chain reaction (PCR) and restriction enzyme digestion in seven breeds of cattle (Nelore, Gyr, Guzerá, Caracu, Charolais, Canchim and Santa Gertrudis). <FONT FACE="Symbol">k</FONT>-Casein had two alleles with the A allele occurring at a higher frequency in Bos indicus breeds (0.93, 0.92 and 0.91% for Gyr, Guzerá and Nelore, respectively). The <FONT FACE="Symbol">b</FONT>-lactoglobulin locus had two alleles in all of the breeds. European breeds had a higher frequency of the <FONT FACE="Symbol">b</FONT>-LG A allele than Zebu breeds. The GH locus had two alleles (L and V) in Bos taurus and was monomorphic (L allele only) in all of the Bos indicus breeds evaluated. The highest frequency for the V allele was observed in Charolais cattle. The markers used revealed a considerable similarity among breeds, with two main groups being discernible. One group consisted of Zebu and Santa Gertrudis breeds and the other consisted of European and Canchim breeds.

Records of 192 Hard henu cattle pertaining to first lactation traits over a period of 6years from 2008 to 2014were collected from history cum pedigree sheets maintained at Cattle breeding farm, Department of Animal Genetics and Breeding Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar. Data were analysed by LSML(Harvey, 1990) using mixed linear model having effect of sire as random and that of year and season of calving as fixed. The first lactation traits studied were first lactation milk yield (FLY), first lactation length (FLL) first service period (FSP) and first calving interval (FCI). The overall least squares means FLY, FLL, FSP and FCI were averaged as 2392.92±70.45 kg,317.70±15.87days, 160.20± 18.08 days and 448.90± 15.13 days, respectively. The effect of period of calving was not significant for all the first lactation traits under study except for FSP. Similarly, the effect of season of calving was not significant for all the first lactation traits except for FSP. The heritability estimates for different first lactation traits were obtained as 0.27±0.34, 0.14±0.39, 0.13±0.38and 0.21±0.26forFLY, FLL, FSP and FCI, respectively. The genetic correlation among first lactation traits were positive and varied from 0.16 to 0.59 except the genetic correlation of FLL with FSP and FCI which was low and negative. The phenotypic correlation among first lactation traits were low to high positive and varied from 0.11 to 0.76, respectively.

The objective of this experiment was to evaluate the effects of replacing coastcross hay NDF by soybean hull (SH) NDF on the lactation performance and eating behavior of ewes and also on the performance of their lambs. Fifty-six Santa Inês lactating ewes (56.1 +/- 6.8 kg of initial BW; mean +/- SD) were penned individually and used in a randomized complete block design with 14 blocks and 4 treatments. Diets were formulated to provide similar concentrations of NDF (56%) and CP (16%). The SH NDF replaced 33 (SH33), 67 (SH67), or 100% (SH100) of the NDF contributed by coastcross hay in a 70% forage-based diet (SH0), resulting in SH inclusion rates of 0, 25, 54, and 85% of the dietary DM. Once a week, from the second to the eighth week of lactation (weaning time), ewes were separated from their lambs, stimulated by a 6-IU i.v. oxytocin injection, and hand milked to empty the udder. After 3 h, milk production was obtained after the same procedure. Quadratic effect for milk production (142.4, 179.8, 212.6, and 202.9 g/3 h) and cubic effect for DMI (2.27, 2.69, 3.25, and 3.00 kg/d) were observed as SH inclusion increased from 0 to 85% of the dietary DM. Milk fat (7.59, 7.86, 7.59, and 7.74%), protein (4.53, 4.43, 4.40, and 4.55%), and total solids (18.24, 18.54, 18.39, and 18.64%) did not differ among the 70% forage-based diet and diets with SH NDF replacing 33, 67, or 100% of the NDF. A linear increase in lactose concentration was observed with SH inclusion. Ewe BW gain during the trial showed a cubic response (0.37, 0.03, 4.80, and 2.80 kg) with SH inclusion. The preweaning ADG of lambs increased linearly, and ADG of lambs after weaning decreased linearly with SH inclusion. Final BW of lambs (2 wk after weaning) did not differ among treatments. Eating behavior observations were conducted with 44 ewes. The same facilities, experimental design, dietary treatments, and feeding management were used. Observations were visually recorded every 5 min for a 24-h period when ewes were 46 +/- 6.8 d in milk. Eating time (min/d, min/g of DMI, and min/g of NDF intake) and time expended in rumination and chewing activities (min/g of DMI and min/g of NDF intake) decreased linearly with the addition of SH in the diets. The inclusion of SH improved DMI and milk production, also reflecting on the BW of lambs at weaning. Milk performance was not affected when SH NDF replaced 100% of hay NDF.