Tomasz M. Gruszecki, Monika Greguła-Kania, Roman Niżnikowski, Mirosław Pięta, Krzysztof Kostro, Anna Szymanowska, Anna Miduch and Ewa Strzelec
The polymorphism of prion protein (PrP) amino acids in codons 136 (A/V), 154 (R/H); and 171 (Q/R/H) was established. Reproductive performance of mother sheep was evaluated analysing the fertility coefficient and litter size, i.e. the number of born and reared lambs. The studies included mothers of synthetic lines BCP - 111 sheep and SCP - 104 sheep born in 2001-2007. In the examined ovine PRNP gene, the following four alleles were identified: ARR, AHQ, ARQ, and VRQ, with the absence of the ARH allele. The highest frequency was determined for the ARR (49.8%) and ARQ (45.8%) alleles. In the studied sheep population, the occurrence of seven different genotypes was reported. It was found that 71.6% of the animals had the genotypes ARR/ARR, ARR/ARQ, and ARR/AHQ, which are regarded as the most resistant to scrapie, while 7.9% of the population had ARR/VRQ-bearing genotypes (low resistance) or ARQ/VRQ ones (high susceptibility to scrapie). The analysis of the obtained results indicates that the PRNP genotype does not affect reproduction efficiency of mothers, or their offspring growth. It was concluded that flock elimination of ewes of genotypes with high and very high susceptibility to scrapie will not reduce the reproduction parameters of ewes or growth of their lambs.
Katarzyna Ognik, Krzysztof Patkowski, Tomasz Gruszecki and Krzysztof Kostro
The aim of the study was to determine the effect of the perinatal period on redox status indicators in the blood of ewes before and after lambing and during lactation. The study was performed on 12 ewes of the synthetic SCP line. Blood for testing of redox parameters was collected seven times: before pregnancy, 1.5 months and 24 h before lambing, 2 and 24 h after lambing, and in the fourth and eighth weeks of lactation. The following blood indices were determined by spectrophotometry: lipid peroxides, malondialdehyde, superoxide dismutase, catalase, plasma total antioxidant capacity, uric acid, urea, bilirubin, and creatinine. The tests showed that during the perinatal period reactions are generated which lead to oxidative stress. Oxidative stress in pregnant ewes was found to increase during the period before lambing and may persist even up to weeks 4-8 of lactation.
Monika Olech, Piotr Kubiś, Czesława Lipecka, Andrzej Junkuszew, Tomasz M. Gruszecki and Jacek Kuźmak
The aim of this study was to investigate the presence of proviral DNA and colostral antibodies in lambs born to and fed by ewes infected with small ruminant lentiviruses (SRLV). It was demonstrated that all 20 lambs tested 24 h after colostrum ingestion were serologically positive with high antibody titres. These gradually decreased with time, and at week 12 all lambs were seronegative. Twenty percent of lambs tested at the 2nd week postpartum were provirus positive by qPCR as a result of consumption of infected colostrum or in utero infection. When tested at three months of life, 95% of the lambs were provirus positive, probably as a result of horizontal transmission of the virus. Since these animals could play an important role in the early propagation of SRLV to susceptible herdmates, early removal of provirus-positive animals could help to prevent new infections.
Mariusz Florek, Andrzej Junkuszew, Wiktor Bojar, Piotr Skałecki, Monika Greguła-Kania, Anna Litwińczuk and Tomasz M. Gruszecki
The objective of the present research was to assess the instrumental and sensory textural attributes of lamb meat depending on the cold storage ageing under vacuum. The research material included two skeletal muscles, i.e. semimembranosus (SM) and rectus femoris (RF) from carcasses of Uhruska lambs. The age of animals ranged from 120 to 135 days. The ageing and muscle influenced significantly shear force and shear energy. However, significantly lower shear force and higher score of tenderness were observed on 7 vs. 2 days of ageing only for SM. The evaluated factors (ageing and muscle) affected slightly and not significantly the parameters of texture profile analysis. The muscle samples after the 7-day ageing showed higher hardness and chewiness. Significant correlation of sensory tenderness with instrumental shear and energy force and springiness was confirmed. The obtained results indicated that vacuum-packed lamb meat during cold storage for 7 days following slaughter develops the sensory attributes, especially tenderness.