Effect of pre- and postpartum supplementation with lipid-encapsulated conjugated linoleic acid on reproductive performance and the growth hormone-insulin-like growth factor-I axis in multiparous high-producing dairy cows.

The objective of the study was to evaluate the effect of prepartum and postpartum (PP) supplementation with 2 isomers of conjugated linoleic acid (CLA) on reproductive parameters and some related metabolic factors in dairy cows. High-producing, multiparous Holstein Friesian cows (n = 60) were allotted to 3 treatment groups: the CLA1 group (n = 20) was supplemented with 70 g of lipid-encapsulated CLA providing 7 g each of cis-9,trans-11 and trans-10,cis-12 CLA from d 21 (d 21) before expected calving until d 7 after artificial insemination (AI), that is, until 77 to 91 d PP; the CLA2 group (n = 20) was supplemented with the same amount of CLA beginning at calving until d 7 after AI; and the control group (n = 20) received an isocaloric, isonitrogenous, and isolipidic diet. Blood samples were taken weekly to measure glucose, insulin, insulin-like growth factor-I (IGF-I), and leptin.

Subsequent effect of subacute T-2 toxicosis on spermatozoa, seminal plasma and testosterone production in rabbits.

Pannon White (n=12) male rabbits (weight: 4050 to 4500 g, age: 9 months) received 2 ml of a suspension containing purified T-2 toxin by gavage for 3 days. The daily toxin intake was 4 mg/animal (0.78 to 0.

Reproductive features and faecal progesterone metabolite profile in female ferrets.

Elevated post-partum progesterone metabolite (P(4) -met) levels have been recently postulated to occur in lactating lynxes. The aims of this study were to monitor reproductive features in female ferrets, changes in the faecal P(4) -met concentrations throughout the breeding season and ovarian activity in post-partum lactating and non-lactating (NL) female ferrets. Our results indicate that coinciding with the results described in the lynx, elevated faecal P4-met concentrations occur in lactating ferrets, furthermore, that the duration of elevated secretion of P(4) seems to be dependent on the duration of lactation (P4-met at delivery, n=47: <500 ng/g; 5-7 days after delivery, during lactation, n=47: ≥ 500-800 ng/g; in females weaned at delivery, n=4: baseline levels).

AluI polymorphism of the bovine growth hormone (GH) gene, resumption of ovarian cyclicity, milk production and loss of body condition at the onset of lactation in dairy cows.

Relationships among GH genotype (AluI polymorphism), parity, metritis and interval from calving to first ovulation, milk production and body condition score (BCS) loss were determined in dairy cows (n=307) on four large-scale farms in Hungary. Cows with systemic signs of puerperal metritis or mastitis were excluded. Time of the first postpartum (PP) ovulation was obtained from milk progesterone profiles.

Bacterial complications of postpartum uterine involution in cattle.

The bacterial contamination of the postpartum uterus is a frequent finding which by itself does not disturb the anatomical and histological restoration of tubular genital tract. The improper balance between uterine infection and the intrauterine antimicrobial self-defence mechanisms, however, often results in complications, such as puerperal metritis, clinical endometritis, pyometra and subclinical endometritis. After reviewing the bacteriology of uterine involution, and the predisposing factors for its bacterial complications, this paper defines the different clinical forms, and summarizes their pathology, furthermore, the recent progress in diagnostic considerations and principles of current treatments for these diseases of bovine genitals.

Endocrine characteristics of late pregnant hyperketonaemic ewes and their reproductive performance following the induction of ovarian cyclicity out of the breeding season.

Ketosis was diagnosed in a flock of Merino ewes that conceived from synchronised oestrus in the early autumn period. On day 140 of pregnancy the ewes were sampled for determination of betaOH-butyrate (BHB), AST, glucose, non-esterified fatty acids (NEFA), total cholesterol (TCH), insulin, T4, T3, cortisol, IGF-1 and leptin. The results were evaluated according to the number of fetuses born some days later and the presence of hyperketonaemia (BHB: > or = 1.

Pregnancy stage and number of fetuses may influence maternal plasma leptin in ewes.

Maternal plasma leptin is elevated in ewes during pregnancy. The authors studied whether there was any relation between maternal plasma leptin and insulin concentrations, the number of fetuses and the circulating and faecal levels of gestagens. At the end of the breeding season in January the ovarian activity of Prolific Merino ewes was induced/synchronised with gestagen + eCG treatment.

Effects of clinical mastitis on ovarian function in post-partum dairy cows.

Mastitis-induced ovarian abnormalities were studied in a field trial. At 1-3 day after calving, > or = 2 parity cows not affected with chronic recurrent mastitis and yielding < 400,000/ml somatic cell count (SCC) individual milk in the previous lactation, were enrolled in the study. Thereafter milk samples were collected three times weekly for 95-100 day for progesterone (P4) assay.

Feeding-unrelated factors influencing the plasma leptin level in ruminants.

The triglyceride content of lipid depots associated with the current feeding level is the primary determinant of leptin gene expression and the circulating leptin level. In laboratory rodents and primates the plasma leptin is influenced also by the age, gender and physiological status (puberty, pregnancy, lactation, postpartum period), and by the health condition such as sepsis due to Gram-negative (GN) bacteria. Some pathologic conditions with intensive cytokine release evoke an increase in plasma leptin, which is thought to depress the subsequent feed intake.

Factors affecting plasma progesterone concentration and the retrospective determination of time of ovulation in cyclic mares.

Factors influencing plasma progesterone concentration were investigated in seven mares. Two-phase logistic curves were fitted (r=0.98) to plasma progesterone concentrations of blood samples collected once daily.

Energy imbalance related predisposition to mastitis in group-fed high-producing postpartum dairy cows.

The energy imbalance related predisposition to mastitis was studied in group-fed postpartum dairy cows (n = 333) kept in 4 large-scale units and producing milk of low somatic cell count (SCC). Blood samples were taken on Days 1-3 after calving for assaying some metabolites and hormones related to the negative energy balance (NEB). If mastitis was diagnosed later, aseptic milk samples were taken to identify the pathogens.

Periparturient endocrine and metabolic changes in healthy cows and in cows affected by mastitis.

Transition from pregnancy to lactation in dairy cows involves considerable metabolic adaptation. Additional stress is incurred during infections such as periparturient mastitis. Multiparous Holstein-Friesian cows kept under normal production conditions (n = 15) were used to evaluate changes in circulating metabolite and hormone concentrations from 5 days before to 5 days after calving.

Biochemical and physiological effects of long-term sublethal T-2 toxin feeding in rabbits.

Effects of 4-7-week feeding of naturally contaminated wheat grains containing 0.284 mg T-2 toxin/kg were investigated on the health, certain serum biochemical parameters and reproductive status of sexually mature, virgin female rabbits. Three of the ten contaminated animals died before the end of the experiment (acute, fibrinous-purulent peritonitis and pneumonia).