Scielo RSS <![CDATA[South African Journal of Animal Science]]> http://www.scielo.org.za/rss.php?pid=0375-158920140001&lang=es vol. 44 num. 1 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>The influence of boar breed and season on semen parameters</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892014000100001&lng=es&nrm=iso&tlng=es The aim of the present study was to demonstrate the influence of boar breed and season on semen parameters. The research material consisted of 31 boars: Polish Large White (PLW), Polish Landrace (PL), and Duroc x Pietrain (D x P), aged 8 to 24 months. The analysed material consisted of 1390 ejaculates, collected during the period January 2010 to October 2012. Semen samples were assessed in terms of semen volume (mL), sperm concentration (x 10(6) m/mL), total number of sperm (x 10(9)), total number of live sperm (x 10(9)) and number of insemination doses obtained from one ejaculate (n). In winter, an increase in sperm concentration was observed for the PLW breed. Moreover, an increase in the volume of semen produced for this breed was noted in summer and autumn. Differences between breeds for the total number of sperm and total number of live sperm were observed for the winter and spring periods. The largest semen volume was noted for the PLW breed (276.4 ± 9.66 mL). However, in the analysis of other sperm parameters, boars of this breed demonstrated the poorest results. The highest insemination dose was obtained from breed D x P in winter (26.0 ± 0.51). Correlation analyses indicated that PLW and D x P boars are the least resistant to higher ambient temperatures, and in summer and autumn this resulted in a reduction in sperm concentration (-0.26 and -0.20, respectively). <![CDATA[<b>Blood metabolite concentrations and postpartum resumption of ovarian cyclicity in Sanga cows</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892014000100002&lng=es&nrm=iso&tlng=es An experiment was conducted to investigate the effect of concentrations of certain blood nutrient-sensitive metabolites and the resumption of postpartum ovarian cyclicity in 16 Sanga cows (mean BCS 5). Blood samples were taken from cows from weeks 1 to 13 (90 days) postpartum, processed and the plasma progesterone concentration measured to determine the resumption of postpartum ovarian cyclicity. The cows were classified as having resumed ovarian cyclicity when a plasma progesterone concentration of ≥1.0 ng/mL was recorded for two consecutive weekly samples. Based on the resumption of ovarian activity, cows were classified as early cycling, late cycling or non-cycling. The plasma glucose, cholesterol, total protein, albumin and globulin concentrations recorded were similar in the early cycling, late cycling and non-cycling cows. The mean blood glucose, cholesterol, total protein, albumin and globulin concentrations were 3.60 mmol/L, 2.47 mmol/L, 83.1 g/L, 29.9 g/L and 52.9 g/L, respectively. Plasma urea concentrations in late (6.57 ± 0.17 mmol/L) and non-cycling (6.59 ± 0.17 mmol/L) cows were higher than in the early cycling (5.99 ± 0.17 mmol/L) cows in weeks 1 to 13 postpartum. In addition, the plasma creatinine concentration in the early cycling cows was higher than in late cycling cows (101.8 ± 1.82 versus 94.0 ± 1.99 mmol/L). Cows with higher plasma concentrations of urea and lower creatinine concentrations were at risk of delayed resumption of postpartum ovarian cyclicity. Results suggest poor nutritional status, especially energy deficiency, as a major underlying factor suppressing the postpartum resumption of ovarian cyclicity. <![CDATA[<b>Effect of L-carnitine supplementation on drake semen quality</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892014000100003&lng=es&nrm=iso&tlng=es This study was conducted to determine the effect on semen quality traits of supplementing the diets of Iraqi drakes with L-carnitine. Forty eight male Iraqi ducks, 30 weeks old, were randomly allocated to four treatments with 12 drakes per treatment group, replicated three times, with four drakes per replicate. The treatment groups consisted of birds fed a diet free of L-carnitine (T1, control group); birds fed a diet containing 50 mg L-carnitine/kg diet (T2); birds fed a diet containing 100 mg L-carnitine/kg diet (T3); and birds fed a diet containing 150 mg L-carnitine/kg diet. The drakes were fed the experimental diets only during the experimental period, which lasted three months. The semen quality traits that were investigated were ejaculate volume, mass and individual motility of spermatozoa, spermatocrit, spermatozoa concentration, percentages of dead and abnormal spermatozoa and acrosomal abnormalities. Supplementing the diet of drakes with L-carnitine at the levels of 50 - 150 mg/kg diet significantly increased ejaculate volume, spermatocrit, mass and individual motility of spermatozoa, and concentration of spermatozoa, while percentages of dead and abnormal spermatozoa and acrosomal abnormalities were decreased. However, T4 (150 mg L-carnitine/kg diet) recorded the best results in relation to all semen quality traits included in this study. Dietary supplementation with L-carnitine improved the semen quality of local drakes; therefore L-carnitine can be used as an efficient feed additive to improve the reproductive performance of male ducks. <![CDATA[<b>Seasonal variation in semen quality of Dorper rams using different collection techniques</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892014000100004&lng=es&nrm=iso&tlng=es The aim of the study was to evaluate the seasonal variation in semen quality of Dorper rams using different semen collection techniques. The study was carried out from January 2012 to January 2013. A general management programme for health control was followed, with water being provided ad libitum throughout the trial, and all rams being fed a 2.5 kg maintenance diet per day. Eleven mature Dorper rams, recording a mean body weight of 69.6 ± 9.2 kg and mean age of 18 ± 4.7 months, were used in the trial. A group of six rams were trained for semen collection with the aid of the artificial vagina (AV), while in the remaining five rams, semen was collected using the electro ejaculator (EE). Immediately after collection, ejaculates were evaluated macroscopically and microscopically for semen volume, semen colour, semen pH, semen wave motion, sperm motility, sperm cell concentration, sperm viability and morphology. The results of the trial generally showed that semen in Dorper rams may be collected using the AV or EE methods throughout the year. However, an overall significant better semen quality collected by the AV versus the EE collection method was recorded. Generally, semen of significantly higher quality was recorded in summer, autumn and spring (both collection techniques). The tendency in the current trial was that the EE technique of semen collection was the less reliable method. Consequently the AV is recommended as the more acceptable method of semen collection in the Dorper. Winter is not generally recommended for semen collection, especially when using the EE. <![CDATA[<b>Chemical features, cholesterol and energy content of table hen eggs from conventional and alternative farming systems</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892014000100005&lng=es&nrm=iso&tlng=es This study was carried out to investigate the effect of conventional farming systems for laying hens (standard cage batteries) and new alternative systems (improved cages and free range), approved by European Union (EU) poultry welfare legislation, on the chemical and nutritional quality of table eggs. The biological material consisted of eggs laid by 1200 Lohmann Brown hens, aged 27 weeks, fed similarly (a corn-wheat-soymeal diet). Conventional AOAC methods were used to analyse the eggs, and gross energy was calculated based on organic matter energy. All data were subjected to ANOVA statistical computation. The eggs produced in conventional cages compared with those laid in free-range farming conditions, presented significantly higher concentrations of total lipids (11.40 ± 0.65 g/100 g vs. 10.78 ± 0.87 g/100 g), cholesterol (211 ± 6.31 µg/egg vs. 202 ± 7.79 µg/60 g egg) and gross energy (0.36 ± 0.007 MJ/egg vs. 0.35 ± 0.012 MJ/egg). Consequently, it could be stated that under similar dietary conditions, the cage-free system influenced hens to produce eggs with a higher nutritive value than in the other systems.