Understanding the link between placental function and fetal growth is critical to comprehend the mechanisms underlying altered fetal growth. This study investigated the relationship between fetal weight and placentome type and size in placentae of singleton and twin fetuses and fetuses within a twin pair from ad libitum-fed ewes at d 140 of pregnancy. In addition, insulin, IGF-I, metabolites, and free AA profiles in fetal, umbilical artery, and vein plasma of singleton and twin fetuses were investigated and used as an indicator of placental nutrient transport. Individual placentae per fetus were dissected, placentomes were classed per type (A to D) and size (light to heavy), and placentome number and individual weight were recorded. Twin fetuses were 16% lighter (P = 0.01) than singletons and had a smaller placenta, with 28% decreased placentome weight (P = 0.03) and 35% fewer placentomes (P = 0.001). Twins also had a different distribution of placentome type and size compared with placentae of singletons, such that twins showed a greater proportion of type B and light placentomes compared with singletons. In twins, umbilical artery plasma had less Glu (P < 0.05) and greater Gln (P < 0.05) concentrations than fetal plasma or umbilical vein plasma, but no differences in AA concentrations were observed between these pools in singletons. Glutamate is a major oxidation energy source for the placenta, and the fetal liver is the net producer of Glu using Gln as its main precursor, indicating that the functionality of the fetoplacental unit may be different between singletons and twins. Twin fetuses had 13% less insulin (P = 0.04) concentrations in umbilical artery plasma than singletons. plasma of twin fetuses had 39% less IGF-I (P = 0.003), 33% less His (P = 0.03), and 22% less Gln (P = 0.02) concentrations and tended to have 44% less Arg (P = 0.07) and 20% less Leu (P = 0.06) concentrations than singletons. Arginine, His, and Leu are examples of AA that can promote insulin secretion, and in turn, insulin can increase fetal IGF-I concentrations. In addition, insulin and IGF-I are important fetal growth factors by stimulating and regulating AA transport across the placenta. Collectively, these results indicate that the functionality of the fetoplacental unit may be different between singletons and twins and that AA transport may be reduced in twin placentae.

Many environmental factors applied postnatally are known to affect milk production of the dam, but to date, the effects of different fetal environments on subsequent first lactational performance of the offspring have not been reported. Four hundred fifty heavy (H; 60.8 kg +/- 0.18) and 450 light (L; 42.5 kg +/- 0.17) dams were randomly allocated to ad libitum (A) or maintenance (M) nutritional regimens from d 21 until d 140 of pregnancy, under pastoral grazing conditions (HA, n = 151; HM, n = 153; LA, n = 155; LM, n = 153). At d 100 of pregnancy, a sub-group of twin-bearing dams was killed and fetal mammary glands collected. From 1 wk before lambing, all remaining dams were fed ad libitum until weaning. After weaning, female progeny were managed and fed under pastoral conditions as 1 group. At 2 yr of age, 72 twin-rearing ewe offspring were milked once a week for 7 wk. Fetuses from M-dams had heavier mammary glands (P = 0.03) compared with A-fetuses. Fetuses from H-dams had greater (P = 0.0008) mammary duct area compared with L-fetuses. At 2 yr of age, M-offspring had greater milk yields at d 7 (P = 0.02) and d 28 (P = 0.09) of lactation and tended to have greater accumulated milk yields (P = 0.11) compared with A-offspring. Ewes born to M-dams showed greater lactose percentage at d 14 (P = 0.002), d 21 (P = 0.06), and d 28 (P = 0.07) of lactation and greater (P = 0.049) accumulated lactose yields and CP (P = 0.06) yields compared with A-offspring. Ewes born to H-dams displayed greater milk yields at d 14 (P = 0.08) and d 21 (P = 0.02) and had greater accumulated milk yield (P = 0.08) and lactose yield (P = 0.04) compared with L-offspring. Lambs born to M-offspring were heavier at birth (P = 0.02) and grew faster until weaning (P = 0.02), matching the milk yield and composition data, compared with their ad libitum counterparts. Birth weight was not affected (P > 0.10) by grand dam size; however, lambs born to H-offspring grew faster from birth until d 49 of age (P = 0.03). In conclusion, dam nutrition during pregnancy affected the resulting milk production of the offspring and composition and growth of their lambs. In addition, dam size affected the milk production of the offspring, lactose yield, and growth of their lambs. These findings are important for furthering our understanding of how the environment to which the female fetus is exposed can affect her subsequent development and her ability to nourish the next generation.

Synergistic effects of ovine-derived cathelicidins SMAP29 and OaBac5mini with the antimicrobials polymyxin B, lysozyme, nisin and lactoferrin were investigated against E. coli O157:H7 and S. aureus 1056 MRSA. Lysozyme showed synergy against E. coli O157:H7 with SMAP29, polymyxin B and lactoferrin. Synergy was also found between SMAP29 and lactoferrin against this host. Against S. aureus 1056 MRSA, lysozyme showed synergy with OaBac5mini, polymyxin B and nisin, while synergy was also found between nisin and OaBac5mini and polymyxin B. Other combinations of the antimicrobials were either additive or non-synergistic.

In temperate climates, the cost of providing feed is greater in winter than in other seasons, causing ewes to be fed restricted rations during some periods of pregnancy. Epidemiological information indicates that undernutrition of the fetus may affect its health and performance in later life (i.e., fetal programming), and these effects may be passed between generations. The primary focus of the results presented in this paper is to examine the effects of feeding levels during pregnancy on a variety of traits from offspring at the fetal stage to 3.5 yr of age and also traits in the grand-offspring. Two studies are reported in which ewes were fed restricted diets during pregnancy, with a variety of fetal traits, offspring traits up to 3.5 yr of age, or grand-offspring traits up to 8 mo of age being measured. Study 2 also considered differences in dam size (heavy vs. light). In study 1, several fetal mammary gland measures indicated that milking ability may be enhanced in offspring from dams fed ad libitum during pregnancy. However, study 2 showed that mammary mass was greater in fetuses from dams fed at maintenance during pregnancy and that contemporaries of these fetuses produced greater protein and lactose yields in their first lactation. In the second lactation, the advantages in protein and lactose yields did not reoccur and ewes from ad libitum-fed dams produced greater fat yield. In study 2, grand-offspring whose granddams were fed at maintenance levels during pregnancy were lighter at birth in both the first and second parturitions than those whose granddams were fed ad libitum during pregnancy. First-parity grand-offspring whose granddams were fed maintenance levels during pregnancy achieved heavier BW by 40 to 50 d of age in the first lactation, which reflected the greater protein and lactose yields; however, no BW differences were present in second-parity lambs at the same age. A smaller proportion of first-parity ewe grand-offspring from heavy granddams that were fed ad libitum during pregnancy reached puberty at approximately 8 mo of age relative to the other granddam size and feeding groups. These results indicate that dam nutrition can affect the yield and composition of milk in their offspring and the BW and reproductive capability of their grand-offspring. Molecular and physiological mechanisms for these changes are being sought.

The development of antimicrobial resistance by pathogenic bacteria has fuelled the search for alternatives to conventional antibiotics. Endogenous antimicrobial peptides have the potential to be used as new antimicrobial substances because they have low minimum inhibitory concentration in vitro, have broad-spectrum activity, neutralise lipopolysaccharides, promote wound healing and have synergistic effects with conventional antibiotics. Farm animals, in particular the blood that is a by-product of the meat and poultry industries, are an abundant, and currently underutilised, source of such antimicrobial peptides. These antimicrobial peptides could be isolated and developed into high-value products such as biopreservatives, topical neutraceutical products and pharmaceuticals. There have been some clinical trials of antimicrobial peptides as pharmaceutical products, but up to now, the trials have shown disappointing results. Further research and development is still needed before such peptides can be commercialised and full advantage taken of this waste product of the meat and poultry industries.