Scheiden van dieren = Weaning of animals

Separation of young animals from their parent(s) can cause welfare problems, if it occurs too early or in a wrong way. In this report we propose criteria for separation of young animals to prevent such problems and indicate for which species the current practice is a risk to cause welfare problems

Elk jaar een kalf blijft optimaal

Met het oog op het vinden van de optimale tussenkalftijd zochten onderzoekers aan de faculteit Diergeneeskunde Utrecht naar het optimale lactatiestadium om koeien te inseminere

Improvement of the Welfare Quality scoring model for dairy cows to fit experts' opinion

After several years of implementation, the original Welfare Quality scoring model for dairy cows appears to be highly sensitive to the number and cleanliness of drinkers and not enough to the prevalence of diseases, and as a consequence may not fit the opinion of some animal welfare experts. The present paper aims to improve the Welfare Quality calculations for the criteria 'Absence of prolonged thirst' and 'Absence of disease' in dairy cows, so that the results are more sensitive to input data and better fit experts' opinion. First, we modified the calculation of 'Absence of prolonged thirst' by linearising the calculation for drinkers' availability to avoid threshold effects. Second, we modified the calculation of 'Absence of disease' by applying a Choquet integral on the three lowest spline-based scores for each health disorder to limit compensation between health disorders. Third, we performed a global sensitivity analysis of the original and the alternative scoring models. Fourth, we compared the results obtained with the original and the alternative models with eight experts' opinions on two subsets composed of 44 and 60 farms, respectively, inspected using the Welfare Quality protocol and on which experts gave their opinion on the overall level of animal welfare. Results show that the alternative model significantly reduced the 'threshold effects' related to the number of drinkers and the compensation between health disorders. On the first subset, the alternative model fits the experts' opinion slightly better than the original model (P = 0.061). On the second subset, the models performed equally. In conclusion, the proposed refinements for calculating scores are validated since they significantly reduced 'threshold effects' and the influence of measures related to drinkers. It also reduced the compensation between health disorders by considering only the three lowest scores and thus increasing the influence of measures related to health disorders, and slightly improve at overall score level the accordance with experts' opinion

A new technique for long term, stress free, cannulation of the lateral ventricle in postpubertal, freely moving, pigs

Intracerebroventricular (ICV) cannulation in adolescent and adult pigs has some unique problems. Placement of the cannula is very difficult due to large individual variability in size and structure of the skull and frontal sinus. Furthermore, the rough behavior of the animals makes it necessary to restrain the animals for ICV treatment, which is disadvantageous when studying responses to stress. In the present study, we developed and employed a cannulation system for the pig brain, based on landmarks on the neurocranium, that enabled us to perform ICV treatment in freely moving post pubertal animals over a long period of time. Furthermore, plasma cortisol concentrations have been determined in freely moving pigs treated ICV with naltrexone or a-CSF (control) to validate the present ICV method for effectivity and stressfulnes

A new technique for long term, stress free, cannulation of the lateral ventricle in postpubertal, freely moving, pigs

Intracerebroventricular (ICV) cannulation in adolescent and adult pigs has some unique problems. Placement of the cannula is very difficult due to large individual variability in size and structure of the skull and frontal sinus. Furthermore, the rough behavior of the animals makes it necessary to restrain the animals for ICV treatment, which is disadvantageous when studying responses to stress. In the present study, we developed and employed a cannulation system for the pig brain, based on landmarks on the neurocranium, that enabled us to perform ICV treatment in freely moving post pubertal animals over a long period of time. Furthermore, plasma cortisol concentrations have been determined in freely moving pigs treated ICV with naltrexone or a-CSF (control) to validate the present ICV method for effectivity and stressfulnes

Elk jaar een kalf blijft optimaal

Met het oog op het vinden van de optimale tussenkalftijd zochten onderzoekers aan de faculteit Diergeneeskunde Utrecht naar het optimale lactatiestadium om koeien te inseminere

When is a cow in estrus? Clinical and practical aspects

Good detection of estrus is critically important in dairy husbandry. Incorrect detection of estrus is related to loss of profit due to extended calving intervals, milk loss, veterinary costs, etc. Detection of estrus remains a major problem despites enormous progress in the knowledge of reproductive physiology of the cow and in development of estrus detection aids. To achieve good estrus detection, many factors have to be taken into account. On one hand a cow has to express estrus and on the other hand the farmer has to detect it. Combined action of several hormones causes physiological changes that lead to ovulation and an environment in the uterus that allows sperm to fertilize the egg. Besides these internal actions, a number of external changes can be observed. When using visual observations, time of the day and time spend on observation have a great impact on detection rates. Many devices are available to aid in estrus detection, such as pedometers, mount devices, temperature, and hormone measurements. Expression of estrus can be influenced by many factors. Heritability, number of days postpartum, lactation number, milk production, and health are known to influence estrus expression. Environmental factors like nutrition, season, housing, herd size, etc. also play a role in estrus expression. To evaluate estrus detection, record keeping is very important; a number of formulas can be used to assess detection efficiency. Besides the farmer, the veterinarian and inseminator can play an important role in estrus confirmation and good insemination strategy. In the end, the time of ovulation and the age of the egg at sperm penetration is critical for conception. Therefore, emphasis in research needs to be on the timing of insemination relative to ovulation, and thus on the detection of ovulatio

Effect of prenatal and postnatal photoperiod on spermatogenic development in the Djungarian hamster (Phodopus sungorus sungorus)

The effect of the pre- and postnatal daylength on the start of spermatogenesis and further testicular development from day 4 up to day 127 was investigated in Djungarian hamsters. Hamsters were either gestated under long (16 h light:8 h dark) photoperiod and reared under long or short (4 h light:20 h dark) photoperiod after birth (L/L and L/S hamsters, respectively), or gestated under short photoperiod and transferred to long photoperiod after birth (S/L hamsters). In L/L and L/S hamsters, spermatogenesis started between day 4 and day 5 (day of birth = day 1), when the first gonocytes entered the S-phase. A, Intermediate and B spermatogonia were first observed on days 6, 8 and 9, respectively. The proliferation pattern of gonocytes and Sertoli cells, studied between day 4 and day 9, did not differ between L/L and L/S hamsters. Hence, the duration of the postnatal photoperiod had no effect on the start of spermatogenesis. The first effect of postnatal photoperiod on spermatogenic development was observed on day 15, when testis weights and tubular diameters were reduced in L/S animals. From day 22 onwards, spermatogenesis was arrested mainly at the mid-pachytene stage, no tubular lumen was formed, and the number of preleptotene spermatocytes was reduced. The ultimate number of Sertoli cells per testis was not affected by postnatal short photoperiod. The duration of the prenatal photoperiod had a clear effect on spermatogenesis after birth. In S/L hamsters, the number of gonocytes per tubular cross-section was reduced on day 4 and 4.5. Gonocyte proliferation was reduced on day 5 and spermatogenesis started one day later. Consequently, A and Intermediate spermatogonia appeared on day 7 and 9, respectively. Sertoli cell proliferation was also shifted to later ages, but the ultimate number of Sertoli cells did not differ from L/L or L/S hamsters. From day 29 onwards, the number of preleptotene spermatocytes was increased in S/L hamsters, indicating that the Sertoli cells in these animals could support more germinal cells. In conclusion, a short postnatal photoperiod does not affect spermatogenesis before day 15 after birth, when further testicular development becomes arrested. A short prenatal photoperiod delays the start of spermatogenesis by one day, alters the proliferation pattern of Sertoli cells, and from day 29 onwards, enables the Sertoli cells to support more germinal cells. The duration of the pre- and postnatal photoperiod did not affect the ultimate number of Sertoli cell

Scheiden van dieren = Weaning of animals

Separation of young animals from their parent(s) can cause welfare problems, if it occurs too early or in a wrong way. In this report we propose criteria for separation of young animals to prevent such problems and indicate for which species the current practice is a risk to cause welfare problems