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ABSTRACT. The edited data set for the estimation of heritability, genetic and phenotypic correlations of fertility traits contained up to 23,402 records from 10,894 cows calved between 2001 and 2015. Heritability estimates for success in first service (FS), gestation length (GL), number of inseminations (NI), insemination outcome (IO), calving interval (CI), calving birth weight (CBW) and days open (DO) were low and ranged between 0.016 (DO) and 0.123 (GL). Repeatability of fertility traits was estimated to vary from 0.021 (FS) to 0.411 (IO). The genetic correlations between DO × CI, DO × NI and CI × NI were positive and nearly perfect (0.98, 0.88 and 0.88, respectively), while those between DO × IO and CI × IO were negative (-0.98 and -1, respectively). Further, the phenotypic correlations between DO × CI, DO × NI, CI × NI, CBW × IO and SF × IO were 0.99, 0.83, 0.83, 0.99 and 1, respectively, while those between DO × IO, CI × IO, GL × IO and NI × IO were -0.99, -0.99, -0.99 and -1, respectively. Overall genetic parameters imply a good practical management in heat stress conditions will be essential for improving fertility efficiency.Keywords: heritability, repeatability, genetic correlation, phenotypic correlation, heat stress. Análise genética de traços de fertilidade em vacas leiteiras Holstein em climas quentes e temperadosRESUMO. Os dados editados para definir a estimativa de herdabilidade, correlações genéticas e fenotípicas de características de fertilidade continham até 23,402 registros a partir de 10,894 vacas paridas entre 2001 e 2015. As estimativas de herdabilidade para o sucesso no primeiro serviço (SF), duração da gestação (GL), número de inseminações (NI), resultado de inseminação (IO), intervalo entre partos (CI), peso ao nascer (CBW) e dias abertos (DO) foram baixas e variaram entre 0,016 (DO) e 0,123 (GL). A repetitividade das características de fertilidade foi estimada e variou entre 0,021 (SF) e 0,411 (IO). A correlação genética entre DO × CI, DO × NI e CI × NI foi positiva e quase perfeita (0,98, 0,88 e 0,88, respectivamente), enquanto que aquela entre DO × IO e CI × IO foi negativa (-0,98 e -1, respectivamente). A correlação fenotípica entre DO × CI, DO × NI, CI × NI, CBW × IO e SF × IO foi 0,99, 0,83, 0,83, 0,99 e 1, respectivamente, enquanto aquela entre DO × IO, CI × IO, GL × IO e NI × IO foi -0,99, -0,99, -0,99 e -1, respectivamente. Os parâmetros genéticos constatados implicam que será essencial uma gestão bem prática na condição de estresse por calor para melhoria da eficiência da fertilidade.Palavras-chave: herdabilidade, repetitividade, correlação genética, correlação fenotípica, estresse por calor.

Abstract. Data including 219 105 test day records of 22 569 first parity Holstein cows in 56 herds were analysed for milk yield, fat content and protein content. Legendre polynomials were used in a random regression model to explain traits curves, additive genetic and permanent environmental effects along days in milk (DIM). Legendre polynomials of order 3 were used to describe additive genetic effects on the traits. For permanent environmental effects, for milk the order of 6 and for fat and protein content the order of 4 were used. Heterogeneity of residual variance was considered. Restricted maximum likelihood (REML) methodology was used to estimate the required parameters. Variations in genetic, permanent environment and residual effects and heritability changes along DIM were computed and illustrated. Daily heritability estimates averaged as 0.22, 0.14 and 0.23 for milk, fat and protein contents, respectively. Minimum correlations between DIM for additive genetic effects were as 0.49, −0.01 and 0.34 for milk, fat and protein contents. There were higher genetic correlations between test day milk yield and protein content compared to fat content. The genetic trend of milk yield has increased over the years from 1971 to 2005, while the genetic trend for fat and protein content declined.

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A 2 × 2 × 3 factorial arrangement of treatments was used to investigate the effects of two levels of dietary crude protein (200 or 240 g kg(-1)) and two inclusion rates of phytase enzyme supplementation (with or without) on performance, jejunum morphology, and some hematological parameters of Japanese quails fed diets based on three graded levels of sesame (Sesamum indicum) meal (0, 120, and 240 g kg(-1) of the diet). A total of 480 Japanese quail chicks were randomly allocated to 12 treatments with 4 replicates of 10 Japanese quails. The results showed that feed intake was decreased in quails fed diets containing 240 g kg(-1) of sesame meal (P < 0.05). Diets with 120 and 240 g kg(-1) inclusion rates of sesame meal improved feed conversion ratio (FCR) in Japanese quail (P < 0.05). Results indicated that the higher level of crude protein improved protein efficiency ratio (PER) and increased feed intake (P < 0.05). The results of jejunum morphology showed that diets containing 120 and 240 g kg(-1) sesame meal increased villus height and the ratio of VH to CD and decreased crypt depth (P < 0.05). Enzyme addition increased serum calcium and phosphorous of Japanese quails (P < 0.05). The liver weight was greater in Japanese quails fed diets containing 200 g kg(-1) crude protein and 120 g kg(-1) sesame meal (P < 0.05). The serum concentration of uric acid was increased in birds that received 240 g kg(-1) protein (P < 0.05). It is concluded that the use of sesame meal improved growth performance (FCR) of Japanese quails. Moreover, serum concentration of calcium and phosphorous was greater in quails with phytase supplementation included in their diet.