Scientific and technical assistance on welfare aspects related to housing and health of cats and dogs in commercial breeding establishments

This Scientific Report addresses a mandate from the European Commission according to Article 31 of Regulation (EC) No 178/2002 on the welfare of cats and dogs in commercial breeding establishments kept for sport, hunting and companion purposes. The aim was to scrutinise recent recommendations made by the EU Platform on Animal Welfare Voluntary Initiative on measures to assist the preparation of policy options for the legal framework of commercial breeding of cats and dogs. Specifically, the main question addressed was if there is scientific evidence to support the measures for protection of cats and dogs in commercial breeding related to housing, health considerations and painful procedures. Three judgements were carried out based on scientific literature reviews and, where possible a review of national regulations. The first judgement addressed housing and included: type of accommodation, outdoor access, exercise, social behaviour, housing temperature and light requirements. The second judgement addressed health and included: age at first and last breeding, and breeding frequency. Judgement 3 addressed painful procedures (mutilations or convenience surgeries) and included: ear cropping, tail docking and vocal cord resections in dogs and declawing in cats. For each of these judgements, considerations were provided indicating where scientific literature is available to support recommendations on providing or avoiding specific housing, health or painful surgical interventions. Areas where evidence is lacking are indicated.

Ovarian and uterine two-dimensional and Doppler ultrasonographic changes in the feline peri-estrus period

OBJECTIVES

The aim of this study was to evaluate two-dimensional and Doppler ultrasonographic changes of the ovary and uterus during estrus and the early post-estrus period in domestic cats.

METHODS

Two-dimensional and Doppler ultrasonographic evaluations of the ovaries and uterus were performed in seven queens on days 1, 3 and 5 of estrus, and 5 days after estrus (AE5).

RESULTS

On day 1, 5.4 ± 0.5 follicles of 2.1 ± 0.1 mm were detected progressively increasing in number and size up to day 5 and then decreased on AE5 (P <0.05). A maximum follicular diameter of 4.1 ± 0.1 mm was achieved on day 5. Both during and after estrus, the uterus was generally hypoechoic compared with the surrounding tissues and delineated by a thin hyperechoic line corresponding to the serosa. In some animals, the uterine layers were distinguished during and after estrus. The blood flow waveforms of the intraovarian and uterine arteries were characterized by a systolic peak and diastolic flow extending throughout the remainder of the cardiac cycle to the next systole. In the uterine artery waveforms, the early diastolic notch was mild or absent during most estrous observations. The resistance index of the intraovarian arteries decreased up to day 5, and then increased on AE5 (P <0.05). The resistance index of the uterine arteries was lower during estrus than in the post-estrus period (P <0.05).

CONCLUSIONS AND RELEVANCE

It is concluded that in the domestic cat, follicular number and diameter as well as ovarian and uterine blood flow changed during and immediately after estrus. Doppler ultrasound proved suitable to evaluate the hemodynamic changes involved in the cyclic remodeling of ovarian and uterine tissues that occurs during and after follicular growth in domestic cats.

Expression pattern of matrix metalloproteinases changes during folliculogenesis in the cat ovary

Matrix metalloproteinase (MMP) has been implicated as having roles in ovarian folliculogenesis. Here, we determined the expression pattern of six MMPs (MMP1, MMP2, MMP3, MMP7, MMP9 and MMP13) and their endogenous tissue inhibitor, TIMP1, during cat follicle growth. Different developmental stage follicles were mechanically isolated and gene expression analysed by real-time qPCR while MMP1, 2, 9 and 13 localization was determined by immunohistochemistry. With the exception of MMP13, the amount of MMP mRNA was lowest in primordial follicles and increased thereafter. Peak levels were detected in early antral follicles for MMP1 (72.2-fold increase above primordial follicle amount), MMP2 (10-fold), MMP3 (57-fold) and MMP9 (2.8-fold). MMP7 transcripts increased 2-fold by the primary follicle stage and then plateaued. MMP13 mRNA peaked in primary follicles (2.5-fold) and was lower in more advanced counterparts. TIMP1 sharply increased (6-fold) in secondary follicles and gradually declined in the later stages. MMP1 and MMP9 expression were expressed in the granulosa cells of all follicle stages. MMP2 was immunoreactive in early and antral follicles, especially at granulosa cells adjacent to the antral cavity. By contrast, the MMP13 was weakly detected in primary follicles onward. In summary, there are distinctive and consistent changes in MMPs and TIMP1 expression during follicle development, suggesting that these enzymes play one or more roles in cat folliculogenesis. In particular, high mRNA and protein expression levels of MMP1 and MMP2, especially at the antral stage, indicate that these enzymes likely are involved in antrum formation and expansion.

Prediction of maturational competence of feline oocytes using supravital staining of cumulus cells by propidium iodide

We examined the relationship between integrity of cumulus cells and nuclear maturation rate after in vitro culture to determine a non-invasive prediction of the maturational competence of feline oocytes. Feline cumulus-oocyte complexes (COCs) were collected from either small (400-800 μm) or large (≥800 μm) follicles. Immediately after collection, cumulus cells were evaluated morphologically (thickness of cumulus cell layers) and stained with propidium iodide (PI), which penetrates only non-viable cells. Cumulus cells without PI staining were judged as having good membrane integrity. After evaluation, COCs were cultured for 30 h and their nuclear maturation rate was determined. The nuclear maturation rate of oocytes derived from large follicles (89.8%) was higher (p < 0.05) than that from small follicles (60.8%). There was no difference in the maturation rate of oocytes from follicles with the same size regardless of cumulus morphology. In contrast, oocytes that had cumulus cells with good membrane integrity showed a higher maturation rate (93.8%) than oocytes with poor cumulus integrity (76.9%) in large follicles (p < 0.05). We conclude that evaluation of membrane integrity of cumulus cells by propidium iodide staining can be used to predict the maturational competence of oocytes.

The effect of ovarian status and follicular diameter on maturational ability of domestic cat oocytes

The objective of this study was to clarify the effect of ovarian status and follicular size on morphological normality and maturational ability of cat oocytes. Ovarian status was classified into inactive, follicular, luteal and prepubertal, and follicles were classified into three groups according to their diameter (400-800, 800-1200 and 1200-2000 µm). In each ovarian status, the number of follicles decreased but the percentage of morphologically normal oocytes increased with the growth of follicles (p<0.05). Only a single follicle that was 1200-2000 µm in diameter was observed in two of the five prepubertal cats. In follicles that were 800-1200 µm in diameter, the percentage of normal oocytes and maturation rate were higher in prepubertal cats than in mature cats (p<0.05). Oocyte diameter tended to increase with the growth of follicles. After oocytes were cultured individually in droplets of maturation medium, the oocyte maturation rate increased with the growth of follicles in each ovarian status (p<0.05). In conclusion, oocytes collected from larger follicles possess higher maturational ability in vitro in sexually mature cats. In prepubertal cats, a higher maturation rate can be obtained from oocytes derived from small follicles compared with in mature cats.