Effect of dam weight and pregnancy nutrition on average lactation performance of ewe offspring over 5 years.

The foetal mammary gland is sensitive to maternal weight and nutrition during gestation, which could affect offspring milk production. It has previously been shown that ewes born to dams offered maintenance nutrition during pregnancy (day 21 to 140 of gestation) produced greater milk, lactose and CP yields in their first lactation when compared with ewes born to dams offered ad libitum nutrition. In addition, ewes born to heavier dams produced greater milk and lactose yields when compared with ewes born to lighter dams. The objective of this study was to analyse and compare the 5-year lactation performance of the previously mentioned ewes, born to heavy or light dams that were offered maintenance or ad libitum pregnancy nutrition. Ewes were milked once per week, for the first 6 weeks of their lactation, for 5 years. Using milk yield and composition data, accumulated yields were calculated over a 42-day period for each year for milk, milk fat, CP, true protein, casein and lactose using a Legendre orthogonal polynomial model. Over the 5-year period, ewes born to heavy dams produced greater average milk (P=0.04), lactose (P=0.01) and CP (P=0.04) yields than offspring born to light dams. In contrast, over the 5-year period dam nutrition during pregnancy did not affect average (P>0.05) offspring milk yields or composition, but did increase milk and lactose accumulated yield (P=0.03 and 0.01, respectively) in the first lactation. These results indicate that maternal gestational nutrition appears to only affect the first lactational performance of ewe offspring. Neither dam nutrition nor size affected grand-offspring live weight gain to, or live weight at weaning (P>0.05). Combined these data indicate that under the conditions of the present study, manipulating dam weight or nutrition in pregnancy can have some effects of offspring lactational performance, however, these effects are not large enough to alter grand-offspring growth to weaning. Therefore, such manipulations are not a viable management tool for farmers to influence lamb growth to weaning.

Identification of reference genes for RT-qPCR in ovine mammary tissue during late pregnancy and lactation and in response to maternal nutritional programming.

The mammary gland is a complex tissue consisting of multiple cell types which, over the lifetime of an animal, go through repeated cycles of development associated with pregnancy, lactation and involution. The mammary gland is also known to be sensitive to maternal programming by environmental stimuli such as nutrition. The molecular basis of these adaptations is of significant interest, but requires robust methods to measure gene expression. Reverse-transcription quantitative PCR (RT-qPCR) is commonly used to measure gene expression, and is currently the method of choice for validating genome-wide expression studies. RT-qPCR requires the selection of reference genes that are stably expressed over physiological states and treatments. In this study we identify suitable reference genes to normalize RT-qPCR data for the ovine mammary gland in two physiological states; late pregnancy and lactation. Biopsies were collected from offspring of ewes that had been subjected to different nutritional paradigms during pregnancy to examine effects of maternal programming on the mammary gland of the offspring. We evaluated eight candidate reference genes and found that two reference genes (PRPF3 and CUL1) are required for normalising RT-qPCR data from pooled RNA samples, but five reference genes are required for analyzing gene expression in individual animals (SENP2, EIF6, MRPL39, ATP1A1, CUL1). Using these stable reference genes, we showed that TET1, a key regulator of DNA methylation, is responsive to maternal programming and physiological state. The identification of these novel reference genes will be of utility to future studies of gene expression in the ovine mammary gland.

Lactation Biology Symposium: maternal nutrition during early and mid-to-late pregnancy: Comparative effects on milk production of twin-born ewe progeny during their first lactation.

Studies using sheep models indicate that the fetal mammary gland is sensitive to maternal nutrition during gestation; however, results have been inconsistent and do not identify critical feeding periods. This study aimed to clarify previous findings by partitioning the period of maternal nutritional manipulation into 2 stages: early and mid-to-late pregnancy. Sixty-six twin-born, twin-bearing ewes, born to dams that were fed either submaintenance, maintenance, or ad libitum during early pregnancy (d 21 to 50 of pregnancy; SmP21-50, MP21-50, or AdP21-50, respectively) and then either maintenance or ad libitum during mid-to-late pregnancy (d 50 to 140 of pregnancy; MP50-140 or AdP50-140, respectively) were milked once a week, starting from d 7 ± 1 postpartum, for 7 subsequent weeks to enable estimation of daily milk yield and composition. Their lambs were weighed weekly. Ewes born to dams fed MP21-50 tended to have greater accumulated milk (P = 0.10), fat (P = 0.07), and NE (P = 0.06) yields over 50 d compared with ewes born to dams fed SmP21-50 and AdP21-50. In contrast, ewes born to dams fed AdP50-140 tended to have greater accumulated milk (P = 0.10) and lactose (P = 0.09) yields compared with ewes born to dams fed MP50-140. Grandoffspring birth weights were unaffected by granddam nutrition during pregnancy. Ewes born to dams fed AdP21-50 weaned lighter lambs (P = 0.05) than ewes born to dams fed AmP21-50 and tended to wean lighter lambs (P = 0.07) than ewes born to dams fed MP21-50 whereas there were no differences between the weaning weights of lambs (P = 0.43) from ewes born to dams fed AdP50-140 and MP50-140. Maintenance nutrition of dams during early pregnancy appears to be associated with an improved lactation performance of ewe offspring. Higher levels of nutrition during mid-to-late pregnancy also appears to improve the first-lactation performance of ewe offspring. Interestingly, although grandoffspring birth weights were unaffected, weaning weight appears to be influenced by granddam early pregnancy nutrition in a manner discordant with the lactational performance of their dam. Results from this study indicate that dam nutrition during early pregnancy can influence the lactational performance of ewe offspring and the BW at weaning of their grandoffspring, which may ultimately affect farmer profits. This highlights the importance of nutritional management of breeding ewes during this period.

Decreasing lengths of stay: the cost to the community.

BACKGROUND: Patients who are discharged earlier from hospital frequently require support from professional and unpaid carers at home after discharge. Hospitals save money per patient by discharging earlier, but it is not known whether the costs to community services and unpaid caters outweigh the savings to the hospital. METHODS: We prospectively studied the total costs, patient satisfaction, time off work and pain scores of 224 patients who underwent elective herniorrhaphy or laparoscopic cholecystectomy and who lived locally before and after re-engineering the elective surgical service. The components of the re-engineered surgical service were a peri-operative unit, pre-admission anaesthetic assessment based on self-reported questionnaires, day of surgery admissions, enhanced patient education, clinical pathways, and post-acute care. RESULTS: The patients treated through the re-engineered surgical service had a significantly shorter length of stay (LOS) (mean LOS: 2.2 vs 3.2 days; P < 0.001) but neither they nor their carers required more time off work. Significant determinants of time off work were smoking, heavy lifting at work and a higher pain score at day 7. Patients treated through the re-engineered surgical service recorded significantly higher satisfaction with their treatment. The cost saving to the hospital outweighed the cost of increased services provided in the community, so that the overall cost of providing treatment was over $200 less per patient through the re-engineered service. CONCLUSIONS: This study demonstrates that changes in care provision that result in shorter LOS and greater cost effectiveness may better meet patients' needs than existing systems.