16 t h International Congress on Animal <strong>Reproduction</strong> 46 Poster Abstracts The study was carried out on 44 multiparous lactat<strong>in</strong>g Holeste<strong>in</strong> cows (FCM = 7759.1 kg) <strong>in</strong> a commercial dairy herd. Scann<strong>in</strong>g of the ovaries was performed by transrectal ultrasound (5 MHz, Ami, Canada) and blood samples for P 4 analysis were collected twice weekly commenc<strong>in</strong>g from day 7 to day 66 after calv<strong>in</strong>g. Serum P 4 concentration was measured by a commercial validated radioimmunoassay kit (Immunotech kit, France). Cows with normal or abnormal postpartum ovarian activities were <strong>de</strong>f<strong>in</strong>ed based on the characteristics of their serum P 4 profiles (Shrestha et al., 2004. Theriogenology 61:637-49). Of 44 cows studied, 22 (50 %) had normal ovarian activity (ovulation occurr<strong>in</strong>g ≤45 days after calv<strong>in</strong>g, followed by regular ovarian cycles); while, 17 (38.6 %) and 5 (11.4 %) had <strong>de</strong>layed first ovulation (DOV) and prolonged luteal phase (PLP), respectively. Data were statistically analysed us<strong>in</strong>g Anova. Logistic regression analysis <strong>in</strong>dicated a significant <strong>in</strong>teraction between P 4 concentration on day 24 after calv<strong>in</strong>g and peak milk yield (kg/day, 75-d postpartum). With the limited number of PLP observed cows <strong>in</strong> the present study, statistical analyses showed that the likelihood of the occurrence of PLP <strong>in</strong>creased by 1.1 for each 1 kg <strong>in</strong>crease <strong>in</strong> peak milk yield of cows with P 4 concentration ≥ 1 ng/ml on day 24 after calv<strong>in</strong>g (P=0.01, 95% CI=1.01-1.15). First postpartum P 4 rise was observed significantly earlier <strong>in</strong> cows with PLP compared to that of the cows with normal ovarian activity (23.2 ± 4.0 vs 32.2 ± 8.38; P
16 t h International Congress on Animal <strong>Reproduction</strong> Poster Abstracts 47 P058 The effect of periparturient propylene glycol adm<strong>in</strong>istration on metabolism and on reproductive performance <strong>in</strong> Holste<strong>in</strong>-Friesian cows Kerestes, M 1 *; Faigl, V 1 ; Győrffy, A 1 ; Márton , A 2 ; Langer, D 1 , Kulcsár, M 1 ; Gaál, T 1 ; Fébel, H 3 ; Húsvéth, F 2 ; Gabor, G 3 ; Bartha, T 1 ; Szenci, O 1 ; Huszenicza, G 1 1Faculty of Veter<strong>in</strong>ary Science, Szent István University, Hungary; 2 Pannon University, Faculty of Agricultural Sciences, Keszthely, Hungary; 3 Institute of Animal Husbandry and Nutrition, Herceghalom, Hungary Negative energy balance <strong>in</strong> the early lactation is often accompanied by <strong>de</strong>creased <strong>in</strong>sul<strong>in</strong> secretion of the pancreatic β-cells and <strong>in</strong>sul<strong>in</strong> resistance of the peripheral tissues. In dairy practice the propyleneglycol (1,2-propanediol, PGL) is often used for prevention of ketosis and fatty liver. We exam<strong>in</strong>ed the effect of periparturient PGL supplementation on metabolic profile, liver lipid content, and on reproductive performance <strong>in</strong> Holste<strong>in</strong> Friesian (HF) cows. The glucose-<strong>in</strong>duced <strong>in</strong>sul<strong>in</strong>-response of the β-cells and the <strong>in</strong>sul<strong>in</strong>sensitivity of peripheral tissues were also <strong>in</strong>vestigated. Fifty-one multiparous HF cows (previous lactation milk yield: 8042±214 kg) <strong>in</strong> a large scale dairy herd were <strong>in</strong>volved <strong>in</strong> the study. The supplemented group (n=20) received PGL pow<strong>de</strong>r correspond<strong>in</strong>g to daily 5.05 MJ NE, from d14 before the expected calv<strong>in</strong>g date till d10 after calv<strong>in</strong>g, poured on the monodiet. The control group (n=30) did not received PGL. Blood samples were taken regularly for ßOHbutyrate (BHB), non esterified fatty acids (NEFA), glucose, <strong>in</strong>sul<strong>in</strong>, <strong>in</strong>sul<strong>in</strong> like growth hormone-I (IGF-I), thyrox<strong>in</strong>e (T 4 ) and 3,3',5, triiodtiron<strong>in</strong>e (T 3 ). On d7-10 after parturition <strong>in</strong> a subsequent of 16 cows (Control=10; PGL=6) liver biopsy was taken to <strong>de</strong>term<strong>in</strong>e the hepatic total lipid content. After biopsy a simultaneous <strong>in</strong>travenous glucose and <strong>in</strong>sul<strong>in</strong> challenge test was performed. Dur<strong>in</strong>g the glucose tolerance test we exam<strong>in</strong>ed the glucose <strong>in</strong>duced <strong>in</strong>sul<strong>in</strong>-response area un<strong>de</strong>r the curve (AUC), the glucose-clearance rate, half time of glucose (T 1/2 ), and maximum <strong>in</strong>sul<strong>in</strong>-response time. From the <strong>in</strong>sul<strong>in</strong>tolerance test we measured the glucose response to the <strong>in</strong>sul<strong>in</strong>. Resumption of cyclicity was monitored by milk progesterone profiles from samples collected 3 times per week. After pre-synchronisation of the ovarian activity with two PGF2a <strong>in</strong>jections at 12 days <strong>in</strong>terval, a GPG protocol and fixed time AI was performed. The PGL supplementation <strong>in</strong>creased the <strong>in</strong>sul<strong>in</strong> concentrations and <strong>de</strong>creased the BHB levels <strong>in</strong> the last days of pregnancy. The treatment had no effect on blood glucose, thyroid hormone and IGF-I levels. The parameters measured dur<strong>in</strong>g the glucose- and <strong>in</strong>sul<strong>in</strong>-tolerance test were not changed. In cows with subcl<strong>in</strong>ical form ketosis the glucose-<strong>in</strong>duced <strong>in</strong>sul<strong>in</strong>-response and the glucose T 1/2 were notably lower. PGL adm<strong>in</strong>istration had no effect on the time of the first pp ovulation (34.1±18vs. 34±16d) and on pregnancy rate (38% vs. 32%) of the animals. The periparturient PGL supplementation somewhat affected the metabolic status of the cows, but its effects rema<strong>in</strong>ed below our expectations. P059 Corpus luteum function and morphology <strong>in</strong> relation to nutrition <strong>in</strong> dairy cows Knijn, HM 1 *, Uijttewaal, MJ 1 , Dieleman, SJ 1 , van <strong>de</strong>n Hurk, R 1 , Zaaijer, D 6 , Vos, PLAM 1 1Farm Animal Health, Faculty of Veter<strong>in</strong>ary Medic<strong>in</strong>e, Utrecht University, The Netherlands; 6 DAP Future Fertility Systems, The Netherlands Anoestrus is an important problem <strong>in</strong> high yield<strong>in</strong>g dairy cows, which can have different causes, for example, a prolonged luteal phase. Recently <strong>in</strong> veter<strong>in</strong>ary practice, abnormal, large, spongy corpora lutea (CLs) were diagnosed <strong>in</strong> non-cyclic dairy cows post partum. These cows received a typical diet with low levels of sugar and rumen fermentable starch, and a relatively high fraction of rumen un<strong>de</strong>gradable starch, <strong>in</strong> comb<strong>in</strong>ation with high levels of prote<strong>in</strong>. The aim of the present study was to create a mo<strong>de</strong>l to <strong>in</strong>duce spongy CLs by feed<strong>in</strong>g this typical diet to dairy cows, and to <strong>in</strong>vestigate its effect on CL morphology and function <strong>in</strong> comparison to control diet. Twenty-four animals were selected based on parity (1-3), lactation state (3-6 months <strong>in</strong> lactation) and normal cyclicity. All animals were synchronized and at the end of the follow<strong>in</strong>g cycle they were allocated <strong>in</strong>to three diet groups; rape- (high rumen fermentable prote<strong>in</strong> > 18% ma<strong>in</strong>ly from rape, low fermentable energy), soya- (high rumen fermentable prote<strong>in</strong> >18% ma<strong>in</strong>ly from soya, low fermentable energy) and control group. Blood samples for progesterone analyses were collected three times a week. The animals were ovariectomized at day 12 (day 0 is estrus) of the third cycle <strong>in</strong> which they were fed the 3 different diets. The obta<strong>in</strong>ed CLs were analysed histologically with regards to surface and size of luteal cells us<strong>in</strong>g as marker 3-β-HSD expression (a pivotal enzyme <strong>in</strong> the synthesis of progesterone). Furthermore, the mRNA expression for IGF-1 (which stimulates the steroidogenesis), and lept<strong>in</strong> (which is a elusive factor l<strong>in</strong>k<strong>in</strong>g reproduction and metabolic status) and their receptors was quantified by Q-PCR technique. Dur<strong>in</strong>g this trial, no spongy CLs have <strong>de</strong>veloped but a large variety of both macro- and microscopic appearance of the CLs has been observed. Remarkably, this was the first time that adipose tissue was <strong>de</strong>scribed <strong>in</strong> the CL, which was frequently observed near the centre or cavity of the CL. In this respect, a significant difference (p