No abstract

Gilts produce less colostrum with lower immunoglobulin G concentration than multiparous sows do. An extra dose of colostrum (30 mL) from multiparous sows was administered to piglets from gilts to ascertain its effects on performance and health in farm conditions, especially in the smallest piglets (birth weight < 1.100 kg; Q1). The control group (CON) consisted of 200 piglets from 18 gilts (50 smallest piglets) and 201 piglets from 16 gilts (52 smallest piglets) formed the supplemented group (SUP). Colostrum supplementation increased the homogeneity of weight (days 21 and 60) and average daily gain (ADG; days 0–10, 0–21, and 0–60) and a decreased use of antibiotics and mortality by diarrhoea (p < 0.05). SUP piglets showed better immune response (presence of antibodies, p = 0.033) against Mycoplasma hyopneumoniae (day 21), porcine reproductive and respiratory syndrome (PRRS; day 60), and influenza (day 60). In the smallest piglets, colostrum supplementation had important effects on mean weight in the first day of life (p = 0.009) and ADG until day 21 (p < 0.05). The smallest piglets had decreased the use of antibiotic treatment use when supplemented (p < 0.05). Colostrum supplementation can improve piglets´ performance and health, although doing so requires increased time and labour in maternity.

Reproduction in swine is mostly carried out through artificial insemination (AI). For this purpose, AI studs collect the ejaculates, analyse the sperm quality, dilute and package to produce seminal doses and ship them to sow farms to carry out the AI. Temperature is controlled during the process to avoid sperm damage. Semen is diluted in the extender in a one‐step or a two‐step process where the second can be isothermic (approximately 32°C) or hypothermic (room temperature 21–22°C). Both techniques are currently performed, and the latter could reduce time and costs, but the literature available comparing the processes is scarce and presents discrepancies. To date, there are no studies about its impact in fertility. This study compared hypothermic two‐step dilution (HTSD) and isothermic two‐step dilution (ITSD) in laboratory and field trial to elucidate whether HTSD has any effect. Ejaculates from 72 boars in nine AI studs were split and processed with both techniques using a high‐performance extender and evaluated in laboratory. Four farms inseminated 345 sows with samples of four of these AI studs, and their fertility and prolificacy were registered. Results show no significant differences between doses prepared by HTSD and ITSD technique, having no impact in laboratory results (percentage of motile sperm, short hypoosmotic swelling test (sHOST) and short osmotic resistance test (sORT), viable sperm, damaged acrosomes, sperm under early apoptosis, high mitochondrial membrane potential (p > .1), fertility (92.2% versus 94.1%, p = .45) or farrowing rate (15.8 ± 0.3 versus 16.1 ± 0.3 p = .46). In conclusion, our results suggest that HTSD of semen on extender could be safely implemented in AI studs under the conditions tested.

Two strategies to improve the conception rates in dairy heifers identified in estrus using tail head painting and inseminated with sexed semen were evaluated. In the first trial, the effect of GnRH injection (100 μg of gonadorelin) at estrus on ovarian responses and conception rates (CR) were verified. A total of 413 virgin Jersey heifers 11 to 12 mo of age were used. All heifers were treated with 25 mg of dinoprost tromethamine at the first day of the AI program. All inseminations were performed 12 h after estrus detection using sexed semen (2.1 million sperm) and the estrus was detected based upon removal of tail-head paint. At estrus detection, heifers were randomly assigned to receive GnRH or not (GnRH = 212 and No GnRH = 201). A subset of heifers (GnRH = 70 and No GnRH = 70), was scanned by ultrasound every 12 h after estrus detection until ovulation. The largest follicle diameter at estrus (LF), ovulatory follicular diameter (OF), ovulation rate (OR), interval between beginning of estrus and ovulation (IEO), and the proportion of heifers presenting late ovulation (LO, ovulation occurred with more than 36 h after the beginning of estrus) were recorded. The GnRH did not influence the LF (13.3 ± 0.9 v. 13.4 ± 0.2 mm; P = 0.87), the OF (13.4 ± 0.3 v. 13.9 ± 0.2 mm; P = 0.17), or OR [98.6% (69/70) v. 97.1% (68/70); P = 0.57]. However, GnRH treatment tended to shorten the IEO (29.2 ± 1.1 h v. 32.0 ± 1.3 h; P = 0.07) and reduced the occurrence of LO (2.9% (2/69) v. 16.2% (11/68); P = 0.02). However, GnRH injection did not influence the CR [GnRH = 47.2% (100/212) v. No GnRH = 51.7% (104/201); P = 0.38]. The second trial evaluated the CRin dairy heifers after the use of single or double insemination dose. A total of 576 Jersey heifers receiving first, second, or third insemination services were used. The heifers were assigned according to sire utilized into one of the three groups (Single 12 h, Double 12 h, or Double 12/24 h). In Single 12 h (n = 193) or Double 12 h (n = 193) groups, heifers received one or two insemination doses (2.1 million sperm) of sexed semen 12 h after estrus detection, respectively. The Double 12/24 h (n = 190) group heifers received two doses 12 h apart from each other (first dose at 12 h and second dose at 24 h after estrus detection). Differences were found between the number of AI services (P = 0.004) on the CR [First = 55.3%a (115/208); Second = 46.1%a (94/204); Third = 34.8% (57/165); P = 0.004]. However, there was no effect of treatment on the CR [Single 12 h = 45.1% (87/193); Double 12 h = 44.0% (85/193); Double 12/24 h = 49.5% (94/190); P = 0.51]. In conclusion, the GnRH injection altered the timing of ovulation, but failed to increase the CR. Furthermore, double insemination doses of sexed semen did not influence the CR in dairy heifers. Dalhart Jersey Ranch-TX, USA and Sexing Technologies-SP, Brazil.

The aims of this study were to separate X-chromosome-bearing bovine sperm by discontinuous Percoll ™ (GE Healthcare Bio-Science AB, Uppsala, Sweden) density gradients, validate the sexing of resultant IVF embryos by PCR, replace the bovine fetal serum (BFS) with BSA in the culture medium, to decrease male development advantage, and verify whether the gradient can be used in an IVF laboratory routine. The gradient was prepared by mixing Dubelcco’s Modified Eagle’s Medium (DMEM; Sigma Aldrich, St. Louis, MO, USA) with Percoll™ isotonic solution with 0.3% BSA, for different densities obtained ranging from 1.110 to 1.123 g mL-1, disposed in 3 layers into 15-mL conical tubes. For sexing, 40 million thawed sperm were overlaid on density gradients. The tubes were centrifuged at 500 g, for 15 min, at 22°C. After centrifugation, sperm sediment was used for IVF. For the control group, a Percoll™ 45, 90% gradient was used. The oocytes were selected from ovaries from slaughterhouse and maturated for 24 h in TCM-199 medium. After fertilization, oocytes and sperm were incubated for 20 h in 5% CO2, in humidified air at 38.5°C. Presumptive zygotes were denuded of cumulus cells, and washed in modified SOF medium and then transferred to 500 μL SOF in four well dishes. Embryo culture was carried out under mineral oil in a humidified atmosphere of 5% CO2, 5% O2, and 90% N2 at 38.5°C, and the cleavage assessed at 46 h and development to the blastocyst stage at Day 7. To obtain embryonic cell DNA for sex determination by PCR, 115 embryos of the sexed and 82 of the control group were used. Two pairs of primers of Y-specific sequences were split in two distinct samples. The first pair detected a sequence of 210 bp, and the second one 196 bp of the bovine Y-chromosome. A third one detected an autosomal sequence of 280 bp, indicating the presence of bovine genomic DNA. PCR multiplex was carried out in the same tube with first and third primers and the PCR of the second one was carried out in another tube. The results were analyzed by X2. Of the sexed group, from a total of 373 oocytes, the cleavage rate was 58.2% (n = 217); 35.6% (n = 133) produced embryos; 36.5% (n = 42) were male embryos and the female embryo rate was 63.5% (n = 73). From a total of 268 control oocytes, the cleavage rate was 63.8% (n = 171); produced embryos 37.3% (n = 100); 57.3% (n = 47) were male embryos and the female rate was 42.7% (n = 35). The Percoll™ density gradient for sperm sexing altered the proportion of IVF embryos toward more females. Because of fast and easy preparation, the gradient can be used routinely in an IVF laboratory and also, BSA can replace FBS for the IVF. FAPESP process number 59357-9 and CAPES