Effects of estradiol cypionate dose as an ovulatory stimulus on reproductive performance of lactating dairy cows during the summer season.

This experiment was designed to evaluate the effects of increasing doses of estradiol cypionate (ECP) on reproductive function of lactating dairy cows during the summer. In Exp. 1, 643 lactating Holstein cows were blocked by parity and assigned to receive 1) an intravaginal P4 device (1.9 g of P4) and 2.0 mg of estradiol benzoate on day -11, 25 mg (i.m.) of dinoprost tromethamine on day -4, 1.0 mg (i.m.) of estradiol cypionate and CIDR withdrawal on day -2, followed by TAI on day 0 (n = 326; ECP-1) or 2) the same synchronization protocol with 2.0 mg of ECP on day -2 (n = 317; ECP-2). In both treatments, cows were TAI on day 0 of the protocol, and cow rectal temperature was measured on days -2, 0, and 7. In Exp. 2, 608 lactating crossbred Holstein × Gir dairy cows were blocked by parity and enrolled to the same treatments as in Exp. 1, but on day 7, cows received one viable embryo into the uterine horn. In Exp. 1, a greater percentage of ECP-2 cows were detected on estrus (81.3 vs. 91.1%, respectively). A treatment × body condition score (BCS) interaction was observed on day 60 pregnancy per AI (P/AI), as ECP-2 cows with a BCS <2.75 had a greater P/AI vs. ECP-1, but an opposite result was observed in cows with a BCS ≥2.75. Regardless of treatment, there were effects of mean rectal temperature and heat stress events on P/AI. Treatment affected the diameter of the ovulatory follicle at TAI (ECP-1 = 15.3 mm vs. ECP-2 = 14.8 mm) and a greater percentage of ECP-1 cows had larger follicles (≥16.5 mm), but ECP-2 resulted in a greater incidence of early ovulatory cows (ovulating before day 0). Therefore, follicle diameter at TAI affected P/AI on day 60 in cows receiving ECP-2 and tended to affect ECP-1 cows. A treatment effect was observed on time to estrus following ECP treatments and a reduced proportion of ECP-2 cows showed estrus at TAI. Regardless of treatment, cows detected on estrus 48 h after ECP administration had a greater P/AI on day 60 vs. cows detected on estrus 24 h. In Exp. 2, a greater percentage of ECP-2 cows were detected on estrus (68.3 vs. 81.4%, respectively). In summary, a greater dose of ECP increased the percentage of animals expressing estrus, but it did not benefit the reproductive function of lactating dairy cows during the summer, regardless if animals were assigned to a TAI or timed-embryo transfer (TET) protocol.

Lung consolidation caused by Mycoplasma hyopneumoniae has a negative effect on productive performance and economic revenue in finishing pigs.

This study aimed to measure the impact of productivity and the consequent economic losses related to lung lesions caused by M. hyopneumoniae. Five-hundred 75 days-old pigs were selected and weighed at the beginning and at the end of the finishing phase to assess the average daily gain (ADG). These animals were evaluated at the slaughter, and samples were collected for laboratory analysis to confirm the presence of M. hyopneumoniae DNA. The lungs of each pig were examined and classified into groups based on the extension of macroscopic lung lesions. Four-hundred eighty-six lungs were examined and 68.5% (n = 333) had macroscopic lung lesions. All pigs with lesions were positive for M. hyopneumoniae in qPCR. Linear mixed regression models (proc Glimmix) were performed on SAS to estimate the effect of macroscopic lung lesion scores on the ADG of finishing pigs. All pairwise comparisons among lesion score groups were performed using p < 0.05. For each increase of one percent in the lesion area, there was a decrease of 1.8 g in the daily weight gain. All the groups had a numerically lower ADG when compared to Group 1 (no lesions). The economic analysis was performed by simulation on Excel to estimate and compare the financial performance of the different lung lesion score groups. The negative correlation found between the group with no lung lesions and the group with more than 15.1% of lesions, showed a statistical difference in ADG, which could mean an opportunity to gain up to $ 6.55 per pig at slaughter. The presence of lesions causes the animals to decrease their productive potential, causing financial loss and generating impacts on the production system.

Effect of adding a gonadotropin-releasing-hormone treatment at the beginning and a second prostaglandin F2α treatment at the end of an estradiol-based protocol for timed artificial insemination in lactating dairy cows during cool or hot seasons of the year.

Our hypothesis was that fertility could be increased in a timed artificial insemination (TAI) protocol based on estradiol (E2) and progesterone (P4) by combining GnRH with E2-benzoate at the start of the protocol to increase circulating P4 during preovulatory follicle development and by using 2 prostaglandin F2α (PGF) treatments at the end to decrease P4 near TAI. Lactating Holstein cows (n=1,808) were randomly assigned during the cool or hot season of the year to receive TAI (d 0) following 1 of 3 treatments: (1) control: controlled internal drug-release insert + 2mg of E2-benzoate on d -11, PGF on d -4, controlled internal drug-release insert withdrawal + 1.0mg of E2-cypionate on d -2, and TAI on d 0; (2) 2PGF: identical to control protocol with addition of a second PGF treatment on d -2; (3) GnRH: identical to 2PGF protocol with addition of a 100-µg GnRH treatment on d -11. Pregnancy diagnoses were performed on d 32 and 60 after TAI. Season had major effects on many reproductive measures, with cool season greater than hot season in percentage of cows with corpus luteum (CL) at PGF (62.9 vs. 56.2%), ovulatory follicle diameter (15.7 vs. 14.8mm), expression of estrus (86.7 vs. 79.9%), ovulation following the protocol (89.7 vs. 84.3%), and pregnancies per artificial insemination (P/AI; 45.4 vs. 21.4%). The GnRH protocol increased percentage of cows with CL (control=56.9%; 2PGF=55.8%; GnRH=70.5%) and P4 at PGF (control=3.28±0.22; 2PGF=3.35±0.22; GnRH=3.70±0.21ng/mL), compared with control and 2PGF protocols. The GnRH protocol increased P/AI at the pregnancy diagnosis at 32d [37.3% (219/595)] and 60d [31% (179/595)] after TAI, compared with control [30.0% (177/604); 25.1% (145/604)], with intermediate results with 2PGF protocol [33.2% (196/609); 28.0% (164/609)]. The positive effects of GnRH treatment on P/AI were only detected during the cool season (GnRH=50.9%; 2PGF=44.2%; control=41.0%) and not during the hot season. In addition, the effect of GnRH was only observed in cows with low P4 (<3ng/mL) at the start of the protocol and not in cows that began the protocol with high P4. Furthermore, presence of CL at PGF interacted with follicle diameter such that cows with a CL at PGF had greater P/AI if they ovulated larger rather than smaller follicles near TAI. Thus, fertility to TAI can be improved by inducing ovulation at the beginning of an E2/P4-based protocol using GnRH treatment, particularly during the cool season of the year and in cows with low P4 at the start of the protocol.

Sorotipos de Streptococcus suis identificados em suínos com meningite no estado do Paraná / Streptococcus suis serotypes identified from meningitis cases in pigs in Parana, Brazil

A total of 76 samples of Streptococcus suis isolated from meningitis cases in pigs from 2005 to 2009 were evaluated. The samples were collected from 3 to 21-week-old pigs raised in 30 farms located in Paraná state, Brazil. The samples of S. suis were obtained as part of routine procedures and were serotyped by coagglutination test using rabbit hyperimmune sera for the serotypes 1 to 9 and ½. S. suis type 2 was the most frequent, followed by serotypes 1, ½ and 3.