We aimed to evaluate the reproductive performance of Nelore lactating cows submitted to a resynchronization 12 days after timed artificial insemination (TAI) with or without a long-acting progesterone (P4-LA) treatment. Nelore cows were submitted to a P4/oestradiol-based TAI protocol (D0 = insemination). On D12, cows in the control group (n = 184) received a new P4 intravaginal device (0.96 g), whereas cows in the P4-LA group (n = 192) received the P4 device and 75 mg P4-LA. Cows identified as non-pregnant (n = 120) by regression of corpus luteum using colour Doppler ultrasonography on D20 had the P4 device removed and received 500ug of sodium cloprostenol, 1 mg of oestradiol cypionate and 300 IU of eCG and were re-inseminated on D22. There was no difference (p > 0.10) in the pregnancy rate at D20, D30 and D60 after first TAI between the control (69%, 59.7% and 57%, respectively) and P4-LA (67%, 55.7%, and 55.2%, respectively) groups. Pregnancy losses were similar between both groups (p > 0.1). For cows submitted to the second TAI, the pre-ovulatory follicle size did not differ (p > 0.1), but the oestrous detection and pregnancy rates were greater (p < 0.05) in the P4-LA group (92.2% [59/64] and 60.9% [39/64], respectively) than in controls (75% [42/56] and 44.6% [25/56]). The cumulative pregnancy rate after two TAIs did not differ (p > 0.1) between control (73.3% [135/184])and groups. The use of P4-LA at 12 days after TAI potentially increases the pregnancy rates for a new early resynchronization strategy associated with the Doppler imaging for pregnancy diagnosis and results in an alternative to perform two TAIs in 22 days in beef cows. K E Y W O R D SBos indicus, corpus luteum, Doppler, pregnancy

The objective of this study was to determine the biochemical profile of dairy cows with induced lactation. For comparison, another group of normally calved cows was used as control. Lactation was induced in multiparous Holstein cows (n=10) with two norgestomet implants (3mg each implant) on day 1. The testing continued with intramuscular norgestomet (3mg/animal) on days 1, 3, 5, 7, 9, 11, 13 and 15. On days 1, 9, 16 to 18 and then every 14 days, bSTr (500mg/animal) was added. On day 16, the intravaginal implant was removed and intramuscular prostaglandin F2α (0.530mg/animal) and intramuscular estradiol benzoate (5mg/animal) were added. On days 16 to 18 dexamethasone (10mg/animal) was added, and from days 18 to 20 intramuscular metoclopramide (100mg/animal) was added. Milking began on day 19 of the induction. Blood was collected for a biochemical profile after 21 days in milk. It was found that urea and triglyceride concentrations were significantly higher in the induced cows (P<0.05). Therefore, it was concluded that the animals that had lactation induced did not present disorders related to the biochemical profile indicating that the hepatic function, renal function and lipidogram of the animals were not affected by the use of the drugs to induce lactation.

The main aim of the current study was to assess the prevalence of anaemia in Holstein dairy cows during the puerperium, and the haematological and biochemical profile of dairy cows with and without anaemia. The study was conducted in seven dairy herds in São Paulo State, Brazil. The evaluated sample comprised a total of 336 Holstein cows. Blood samples were collected at postpartum day 25 ± 3. Haematological analysis included white blood cell, red blood cell and platelet count, haematocrit value, haemoglobin concentration, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration. The biochemical profile encompassed cholesterol, non-esterified fatty acids, β-hydroxybutyrate, albumin, globulin, fibrinogen, calcium and total bilirubin concentrations. The prevalence of anaemia was 16.3% in all herds, and this was not affected by clinical diseases, milk production, parity and body score condition. Moreover, anaemic cows had lower red blood cell count, haematocrit, haemoglobin, serum cholesterol and calcium concentrations and higher white blood cell and platelet counts, mean corpuscular haemoglobin, red cell distribution width, non-esterified fatty acids, β-hydroxybutyrate, fibrinogen and globulin concentrations when compared with non-anaemic cows. The results indicate changes in energy balance and an inflammatory process in anaemic cows.