Plasma progesterone concentration in beef heifers receiving exogenous glucose, insulin, or bovine somatotropin

Three experiments were conducted to evaluate plasma concentrations of glucose, insulin, IGF-I, and progesterone (P4) in pubertal beef heifers receiving exogenous glucose, insulin, or sometribove zinc. All heifers used had no luteal P4 synthesis but received a controlled internal drug-releasing device containing 1.38 g of P4 to estimate treatment effects on hepatic P4 degradation. In Exp. 1, 8 pubertal, nulliparous Angus x Hereford heifers (initial BW = 442 +/- 14 kg; initial age = 656 +/- 7 d) were randomly assigned to receive, in a crossover design containing 2 periods of 10 h, intravenous (i.v.) infusions (10 mL) of insulin (1 mu g/kg of BW; INS) or saline (0.9%; SAL). Treatments were administered via jugular venipuncture in 7 applications (0.15 mu g insulin/kg BW per application) 45 min apart (from 0 to 270 min). Blood samples were collected immediately before each infusion as well as at -120, -60, 330, 390, and 450 min relative to the first infusion. Heifers receiving INS had greater (P < 0.01) plasma insulin, reduced (P <= 0.04) plasma glucose and IGF-I, and similar (P = 0.62) plasma P4 concentrations compared with SAL heifers. In Exp. 2, the same heifers were assigned to receive, in a similar experimental design as Exp. 1, i.v. infusions (10 mL) of 1) insulin (1 mu g/kg BW) and glucose (0.5 g/kg BW; INS+G) or 2) SAL. Heifers receiving INS+G had greater (P <= 0.02) plasma insulin, glucose, and P4 but reduced (P = 0.01) plasma IGF-I concentrations compared with SAL heifers. In Exp. 3, the same heifers were assigned to receive, in a crossover design containing 2 periods of 14 d, subcutaneous (s.c.) injections of 1) 250 mg of sometribove zinc (BST) or 2) SAL. Blood samples were collected 3 h apart (0900, 1200, 1500, and 1800 h) from heifers on d 6, 8, and 10 relative to treatment administration (d 1). Heifers receiving BST had greater (P < 0.01) plasma glucose and IGF-I and similar (P >= 0.67) plasma insulin and P4 concentrations compared with SAL heifers. Results from this series of experiments suggested that concurrent increases in glucose and insulin are required to reduce hepatic catabolism and increase plasma concentrations of P4 in bovine females.

Fertility-associated antigen on Nelore bull sperm and reproductive outcomes following first-service fixed-time AT of Nelore cows and heifers

The objective was to determine whether the presence of fertility-associated antigen (FAA) on sperm collected from Nelore (Bos indicus) bulls can be used to assess potential fertility of sperm for use at first-service fixed-time AI (TAI). Six Nelore bulls were selected based on FAA status (FAA-negative: N = 3; FAA-positive: N = 3) and the ability to produce neat semen with >= 70% morphologically normal sperm and 60% estimated progressive motility before cryopmservation. In Experiment 1, suckled multiparous Nelore cows (N = 835) were evaluated for body condition score (BCS) and received an intravaginal progesterone device (CIDR) and 2.0 mg of estradiol benzoate (Day 0). on Day 9 the CIDR was removed, 12.5 mg of PGF(2 alpha) and 0.5 mg of estradiol cypionate were administered, and calves were removed for 48 h. All cows received TAI on Day II (48 h after CIDR removal). Pregnancy per TAI (P/TAI) was not different between FAA-positive and FAA-negative bulls (41.5% vs. 39.3%, respectively). There was an effect of AI technician on P/TAI (36.0% vs. 43.9%; P < 0.05) and BCS tended to affect P/TAI (P = 0.09), as cows with BCS >= 2.75 were 1.4 times more likely to become pregnant compared with cows with BCS < 2.75. In Experiment 2, nulliparous Nelore heifers (N = 617) were evaluated for BCS and received a CIDR and estradiol benzoate (2.0 mg) on Day 0. on Day 7, all heifers received PGF(2 alpha) (12.5 mg). on Day 9, CIDR inserts were removed and all heifers received estradiol cypionate (0.6 mg) and 200 IU eCG. All heifers received TAI on Day 11 (48 h after CIDR removal). Pregnancy/TAI was different (P = 0.04) between FAA-positive and FAA-negative bulls (33.7% vs. 40.7%, respectively). Presence of FAA on sperm was unsuccessful in assessing the potential fertility of sperm for use in TAI. (C) 2012 Elsevier B.V. All rights reserved.

Effects of calcium salts of polyunsaturated fatty acids on productive and reproductive parameters of lactating Holstein cows

Two experiments evaluated milk production, serum progesterone and insulin, and reproductive performance of lactating Holstein cows receiving or not receiving Ca salts of polyunsaturated fatty acids (PUFA), or receiving Ca salts of PUFA at different daily frequencies. In experiment 1, 1,125 cows randomly distributed in 10 freestall barns were enrolled. Barns were assigned randomly to receive a high-concentrate diet containing (PI?) or not containing (control, CON) 1.1% (dry matter basis) Ca salts of PUPA. Diets were offered 6 times daily, whereas the Ca salts of PUFA were included in the PF treatment in the first feeding of the day. In experiment 2, 1,572 cows were randomly distributed in 10 freestall barns, which were assigned randomly to receive a diet similar to PF, but with Ca salts of PUFA included only in the first feeding of the day (PF1X), or equally distributed across all 6 feedings (PF6X). During both experiments, cows were artificially inseminated 12 h after the onset of estrus. Once per month, cows that did not conceive to artificial insemination were assigned to a fixed-time embryo transfer protocol. Pregnancy was determined via transrectal ultrasonography 28 and 60 d after expected ovulation. Pregnancy loss was considered in cows that were pregnant on d 28 but nonpregnant on d 60. During both experiments, feed intake, milk yield, and milk protein and fat content were recorded weekly. Blood samples were collected concurrently with embryo transfer. During experiment 1, feed intake was similar between treatments. Compared with CON, PF cows had greater milk yield (37.8 vs. 35.3 kg/d), and reduced milk fat content (3.41 vs. 3.55%). However, PF cows had reduced pregnancy losses per service compared with CON (12.6 vs. 18.3%). Serum progesterone was greater and serum insulin tended to be greater in primiparous cows receiving PF compared with CON cohorts (4.50 vs. 3.67 ng of progesterone/mL, and 10.4 vs. 7.5 mu UI of insulin/mL). During experiment 2, no treatment effects were detected for feed intake, milk yield, or milk fat, whereas PF1X cows tended to have reduced pregnancy losses per service compared with PF6X (14.4 vs. 18.4%). In summary, feeding Ca salts of PUFA to dairy cows increased milk production, did not alter feed intake, and reduced pregnancy losses per service. Further, the total daily amount of Ca salts of RITA should be fed during the first feeding of the day to optimize its benefits on pregnancy maintenance of dairy cows.

Ultrasonographic and endocrine aspects of follicle deviation, and acquisition of ovulatory capacity in buffalo (Bubalus bubalis) heifers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Myelopathy in Holstein x Gir calves in Brazil

The central nervous system (CNS) is susceptible to a variety of insults, including infectious, toxicologic, and genetic disorders. Inherited disorders can be evident at birth or might not be apparent until later in the 1st year of life or beyond. Most neurological disorders are recognized in the dog and cat with fewer examples in farm animals.(1) This paper contains the 1st report of the clinical and pathological features of a degenerative myelopathy in Holstein X Gir crossbred calves in Brazil.

Synaptonemal complex analysis of the Holstein-Friesian, Piemontese and Simmental breeds of Bos taurus taurus

The synaptonemal complex (SC) of specimens of Sos taurus taurus from the Holstein-Friesian, Piemontese, and Simmental breeds, was analysed. The analysis included quantification of the frequency of various types of abnormalities in the SC, and the frequency of calls with SC abnormalities. All animals had 29 autosomal bivalents and one sexual bivalent and the most frequently recorded abnormality was pairing failure. The number of cells with abnormalities in the Holstein-Friesian breed was 29.41%, in the Piemontese breed was 30.00% and in the Simmental breed it was 29.54%. The subspecies Bos taurus taurus had 29.63% of cells showing abnormalities with 57.33% of these abnormalities occurring in zygotene and 42.67% occurring in pachytene. Statistical analyses showed that there were no significant differences in the number of cells with SC abnormalities among the breeds studied. The frequency of cells with abnormalities, and the efect on the fertility of the Holstein-Friesian, Piemontese and Simmental breeds are discussed.

Follicle deviation and ovulatory capacity in Bos indicus heifers

The objectives of Experiment I were to determine the interval from ovulation to deviation, and diameter of the dominant follicle (DF) and largest subordinate follicle (SF) at deviation in Nelore (Bos indicus) heifers by two methods (observed and calculated). Heifers (n = 12) were examined ultrasonographically every 12 h from ovulation (Day 0) to Day 5. The time of deviation and diameter of the DF and largest SF at deviation did not differ (P > 0.05) between observed and calculated methods. Overall, deviation occurred 2.5 +/- 0.2 d (mean +/- S.E.M.) after ovulation, and diameters for DF and largest SF at deviation were 6.2 +/- 0.2 and 5.9 +/- 0.2 mm, respectively. Experiment 2 was designed to determine the size at which the DF acquires ovulatory capacity in B. indicus heifers. Twenty-nine heifers were monitored every 24 h by ultrasonography, from ovulation until the DF reached diameters of 7.0-8.4 mm (n = 9), 8.5-10.0 mm (n = 10), or >10.0 mm (n = 10). At that time, heifers were treated with 25 mg of pLH and monitored by ultrasonography every 12 h for 48 h. Ovulation occurred in 3 of 9, 8 of 10, and 9 of 10 heifers, respectively (P < 0.05). In summary, there was no significant difference between observed and calculated methods of determining the beginning of follicle deviation. Deviation occurred 2.5 d after ovulation when the DF reached 6.2 mm, and ovulatory capacity was acquired by DF as small as 7.0 mm. (c) 2008 Elsevier B.V. All rights reserved.

Uveitis due to anaplasmosis in a newborn Holstein calf

Relata-se o caso de um bovino com, aproximadamente, seis horas de vida, apresentando histórico de febre, apatia, inapetência e desconforto ocular. No exame oftálmico rotineiro, encontraram-se valores do teste da lágrima de Schirmer aumentados, diminuição da pressão intra-ocular, hemorragia conjuntival, uveíte anterior, edema corneal e injeção ciliar em ambos os olhos. Coletou-se amostra de sangue para realização de esfregaço sangüíneo, hemograma e bioquímica sérica. No esfregaço visibilizaram-se corpúsculos de Anaplasma marginale em hemácias parasitadas. Quanto à bioquímica sérica, não foram observadas alterações. Os mesmos exames foram realizados na mãe do animal tendo como resultado a positividade para A. marginale. Para o controle da uveíte foi utilizada uma única aplicação de 0,5ml de betametasona a 5%, por via subconjuntival, em cada um dos olhos. Para o tratamento da anaplasmose, seguiu-se o protocolo a base de 10mg/kg de oxitetraciclina, por via intramuscular profunda, a cada 12 horas. Diante os achados oftálmicos e a presença de corpúsculos de A. marginale em hemácias parasitadas, contatou-se, ser um caso de uveíte crônica secundaria a doença sistêmica, factível com Anaplasmose.

Evaporative cooling and cutaneous surface temperature of Holstein cows in tropical conditions

Foram estudados os efeitos da temperatura cutânea (Ts) sobre a taxa de termólise por evaporação cutânea (Es) de vacas Holandesas cronicamente expostas ao sol, considerando a pigmentação do pelame. Dezesseis vacas puras de origem foram medidas quanto à evaporação e à temperatura cutâneas às 13 h, após 6 horas de exposição ao sol, no mesmo local (flanco, pescoço e glúteo) e considerando separadamente as malhas negras e as brancas. A evaporação cutânea foi medida por meio de cápsula ventilada. Nas áreas negras a taxa de sudação (138,9 ± 8,5 g.m-2.h-1), a taxa de termólise por evaporação cutânea (93,3 ± 5,7 W.m-2) e a temperatura da superfície cutânea (33,1 ± 0,2°C) foram maiores que nas áreas brancas (109,5 ± 9,7 g.m-2.h-1, 73,6 ± 6,5 W.m-2 e 32,6 ± 0,2°C, respectivamente). Há uma relação exponencial entre evaporação e temperatura cutâneas, que pode ser representada pela equação Es = 31,5+3,67 exp{(Ts-27,9)/2,19115}, com coeficiente de determinação r²=0,68. A taxa de termólise por evaporação cutânea permanece quase constante (cerca de 48 W.m-2) até que a temperatura cutânea atinge aproximadamente 31°C.

Follicular dynamics and production of oocytes in young Nellore heifers with energetic supplementation

To verify the effects of energy supplementation and fat on follicular dynamics, metabolic profile and the production of oocytes, 15 young heifers (Bos taurus indicus) with an average age of 14 months and with an initial weight of 256.35 kg were assigned to two treatments according to weight and follicular population as evaluated by ultrasonography: in T1 (1.0 × M), animals received 100% of the energy requirements for maintenance; in T2 (1.7 × M), animals received 170% of the energy requirements for maintenance, achieved by the addition of 200 g of Megalac®. After a period of adaptation to the diet, the treatments, blood collection and follicular aspirations were started using a randomized design. The dry matter intake and weight gain were lower in the 1.0 × M group than in the 1.7 × M group. No differences were found in the plasma progesterone concentrations, albumin, glucose, urea or gonadotropin (FSH and LH) levels between the groups. The mean concentrations of cholesterol were higher in the 1.7 × M group. The total number of small (<4 mm) and medium follicles (4-8 mm) was not altered by the treatments, but the number of small follicles increased on days 1 and 2 of the estrous cycle, with higher values found in the 1.7 × M group. The average of the oocytes also increased (9.50±2.1 and 12.5±4.4 for the 1.0 × M and 1.7 × M groups, respectively). The rapid increase in the amount of energy offered in the diet changes the amount of follicles and oocytes available for follicular aspiration (OPU) in young heifers without changing their metabolic profile.