Lambs are more stressed at early weaning when housed with their twin.

The objective of this study was to compare the behavioural and immunological responses of twin lambs housed together with their siblings or not after weaning. The study was performed with seven multiparous Milchschaf ewes and their twin lambs (n = 14), which were weaned abruptly at 63 days of age and assigned to two experimental groups: (1) lambs that were housed together with their sibling after weaning (group GT, n = 6) and (2) lambs that were separated from their siblings and remained with other lambs from the same flock (group GS, n = 8). Before and after weaning, the distance between twins, the number of times in which the sibling was the closest lamb, the lambs' behaviours, and the average daily gain were recorded. The lambs' immune response was assessed with the phytohemagglutinin skin test after weaning. The closest lamb before weaning was the sibling in all cases (P < 0.0001 for all). The frequency in which GT lambs were observed closest from its twin increased on the day of weaning (P = 0.002). During the day of weaning, GT lambs vocalised and paced more than GS lambs (P = 0.001 and P = 0.01, respectively). Twenty-four h after the phytohemagglutinin injection, the skinfold thickness was greater in GS than GT lambs (P = 0.03). In conclusion, twin lambs housed together with their siblings were more stressed at weaning, displaying more intensive behavioural changes and a poorer immunological status than twin lambs housed separated from their siblings.

Seasonality of the stress response in goat bucks when there is use of electroejaculation for semen collection.

Electroejaculation (EE) is frequently used to collect semen, but this procedure is both stressful and painful. In seasonal-breeding species the sensitivity to stressors might vary with season of the year when semen collection occurs, therefore, the present study was conducted to compare the responses when imposing the EE procedure, stress response to EE and fresh semen characteristics in goat bucks throughout the year. Semen was collected using EE from goat bucks once in autumn (mid-breeding season), winter (transition to the non-breeding season), spring (non-breeding season), and summer (beginning of the breeding season). The number of pulses applied during ejaculation was larger in the autumn and spring than winter and summer months. The number of vocalizations/pulse while bucks were ejaculating was greater in the summer than winter and spring months. The increase in heart rate was greater in spring than summer months. Cortisol concentration was least in the autumn, and concentration of creatine kinase (CK) was greatest in summer. Sperm mass motility was greater in autumn than spring months. Spermatozoa concentration, total number of spermatozoa ejaculated, motile spermatozoa ejaculated, and progressively motile spermatozoa were greater in the autumn and spring than in the winter and summer months. The bucks were less stressed by imposing EE procedures in the autumn, and buck responses were greater in the spring-summer period. Bucks had a greater incremental increase in serum CK and number of vocalizations in the summer months, indicating there was a greater muscular damage and quite likely pain associated with lesser semen quality.

Collagen, glycosaminoglycans and matrix metalloproteinase-2 and metalloproteinase-9 in the cervix of the ewe during prepubertal development.

The tortuous nature of the ovine cervix restricts the transcervical passage of the cannula, and many studies have aimed to understand the endocrine mechanism of the remodelling of cervical tissue in adult ewe. However, little is known about the remodelling of the cervical tissue during the prepubertal development of the lambs. To obtain histochemical and biochemical evidence about the nature of the prepubertal development of the cervix of the ewe, cervices of Corriedale lambs obtained at 0, 1, 2, 4, 6 and 8 months of age (n = 5 to 6 in each) were processed. Neutral and acidic glycosaminoglycans (by PAS-Alcian stain) were weakly in the cervical stroma and not shown change during the development, whereas the percentage volume of fibrillar collagen (by van Gieson stain) increases throughout the experimental period in the superficial fold stroma and deep wall stroma (p < 0.05). The relative cervical weight (g/kg of body weight) and the collagen concentration (by spectrophotometry, mg/mg wet tissue) showed an early decreasing phase from months 0 to 4 and a later increasing phase from months 4 to 8 (p < 0.05). The latent form of matrix metalloproteinase-2 (MMP-2) detected by gelatin zymography (ng/mg protein) decreased from months 0 to 2 and increased from months 4 to 8, whereas the activated form decreased from months 0 to 2, remained low until month 6 and then recovered on month 8 (p < 0.0001). Data suggest that the relative cervical weight biphasic pattern during the development is related to MMP-2-dependent changes in the collagen content.

Administration of cloprostenol and oxytocin before electroejaculation in goat bucks reduces the needed amount of electrical stimulation without affecting seminal quality.

Electroejaculation (EE) is a widely used semen collection technique; but, it is stressful and painful for the animals. Considering these concerns, it may be important to develop practices to decrease the negative implications of EE on animals. Oxytocin and prostaglandin-F2alpha (PGF2α) stimulate the contractions of the muscles of the male genital tract. Therefore, the aim of this study was to analyze the effectiveness of the administration of oxytocin and/or a PGF2α analogue (cloprostenol) to bucks in relation to their stress response and sperm parameters before semen collection by EE was performed. Semen was collected with EE from 12 Gabon bucks in a 2 × 2 factorial arrangement (factors: with or without oxytocin, with or without cloprostenol). Each treatment was applied to different animals every 3 to 6 days, allowing all the animals to receive all the four treatments. The treatments applied to bucks before EE were as follows: 1) control (ConT), bucks received no hormonal treatment; 2) oxytocin (OxyT), bucks received 10 IU of oxytocin intramuscularly (IM) 30 s before beginning the EE; 3) PGF2α (PgT), bucks received 250 µg of cloprostenol IM 5 min before beginning the EE; and 4) oxytocin plus PGF2α (OxPgT), animals received treatment with both OxT and PgT. The number of electrical pulses, time length needed to achieve ejaculation, number of vocalizations, creatine kinase (CK) concentration and sperm parameters in goat bucks were recorded. The administration of cloprostenol and oxytocin before EE shortened the procedure and decreased the number of pulses and the pulse/voltage applied (P = 0.02 for all). This treatment also tended to decrease the number of vocalizations (P = 0.067). There were no treatment effects in the initial values; neither were there increases in heart rate and rectal temperature, or CK concentration. Seminal variables were not affected by the treatments. In conclusion, it would be important to consider the combined application of cloprostenol and oxytocin before EE, as it can shorten the process, reducing the electrical stimulus with positive effects on animal welfare and without affecting seminal quality in goat bucks.