Early life is critical for the development of an organism. External factors alter placental efficiency which can lead to consequential effects. The objective of the current study was to (1) examine placental characteristics and molecular factors affected by nutrient restriction (2) evaluate the mitigating properties of melatonin in a nutrient restricted pregnancy in regard to circadian, myogenic and adipogenic factors in fetal muscle and (3) evaluate the effects of prenatal and postnatal melatonin supplementation on offspring performance. In study 1, cows were fed a control (CON) or a 60% restricted (RES) diet from day 140 to 240 of gestation. Animals were slaughtered for placentome collection. Nutrient restriction increased vessel perimeter, downregulated genes related to blood vessel development, and upregulated ribosomal and translation factor expression. In lieu of downregulated vessel development, a compensatory effect geared towards nutrient-transport apparent. The 2nd study utilized spring-calving and fall-calving heifers in two trials with a 2 x 2 x 2 factorial design. Treatments were adequately-fed (ADQ) or 60% restricted (RES) dams along with melatonin (MEL) or no melatonin (CON) from day 160 to 240 of gestation. Cesarean sections were performed either in the morning (AM) or afternoon (PM). Circadian, myogenic and adipose-related factors in fetal loin muscle (LM) were analyzed. Fetal LM from the spring-calving (fall) group experienced a downregulation of circadian genes, myogenic genes and tendency for downregulation in lipolysis genes. Fetal LM collected from the fall-calving (summer) group had interactions in myogenic expression. Results demonstrate photoperiod and seasonal effects on nutrient restriction and melatonin supplementation in regard to tissue prioritization. In study 3, melatonin was supplemented to calves during the prenatal and postnatal period in a 2 x 2 factorial design. Supplementation did not alter offspring performance. A lack of differences may be attributed to similar endogenous melatonin levels in dams. Despite no differences in calf performance, tendencies for decreased milk yield and fat were observed in MEL versus CON dams. This demonstrates that melatonin may influence feed efficiency in calves that receive less nutrients during early life. The programming effects of melatonin after birth appear to be low.

The thrifty phenotype hypothesis proposes reduced nutrition alters the trajectory of development of metabolic regulatory systems to produce a phenotype better fitted to an environment of decreased later-life nutrient availability. Because organisms have physiological mechanisms for coping with poor nutrition, they may have sociobehavioral mechanisms as well. Aggressive behavior, especially in the context of feeding competition, may be advantageous in such environments. There could be an association between aggression and intrauterine growth restriction (IUGR), which can result from low maternal food intake during pregnancy. The main hypotheses of this study are [1] IUGR offspring demonstrate higher rates of aggressive behavior and [2] IUGR offspring attain higher ranks. Behavioral observations were conducted on 22 juvenile baboons (Papio sp., ages 3-5 yrs) living in groups. Male IUGR (n = 4) and female IUGR (n = 5) were offspring of mothers fed 70% the same feed eaten by control (CTR) mothers in pregnancy and lactation. CTR males (n = 8) and CTR females (n = 5) were offspring of mothers fed ad libitum. Some authorities recommend this moderate level of dietary restriction for health and longevity. Offspring have not experienced dietary restriction since weaning. IUGR, compared to CTR, showed significantly increased rates of aggressive behavior, especially threat displays. Differences were more dramatic in males than in females. IUGR baboons performed the affiliative display behaviors lipsmack and chatter at elevated rates too, perhaps to counteract the effects of increased aggressive displays. IUGR females exhibited increased rates of stereotypical chewing behavior, while IUGR males exhibited decreased rates of play behavior, possibly indicating elevated anxiety levels. There was only limited support for condition-based differences in rank. Elevated rates of aggression in IUGR baboons may reflect an aggressive behavioral phenotype that enhances fitness by improving access to resources. Alternatively, they could be a non-adaptive result of neurodevelopment with a potentially negative impact on fitness. Unraveling the dynamic relationship between experiences and development is essential for understanding how phenotypes are formed. This will improve the ability of mothers to assess benefits of different nutritional strategies, leading to healthier individuals not just during growth and development, but throughout life.

The objective of this study was to determine breed specific effects of nutritional insults during gestation on regulation of muscle and adipose tissue growth in beef cattle offspring during fetal and early postnatal development. Angus and Brahman heifers were randomly assigned to 1 of 2 dietary treatments consisting of 100% or 60% based on net energy requirements for gestating heifers. Nutritional treatments were imposed from day 50 to 180 of gestation. Fetuses harvested at 180 days of gestation had smaller frames and spared critical organs. Gene expression in several fetal tissues indicated potential for compensatory growth. Postnatally, Brahman offspring weighed less than Angus offspring and had smaller heads and heart girths along with decreased expression of growth and myogenic genes in the Longissimus dorsi. There were no differences in growth or myogenic gene expression within the Longissimus dorsi due to treatment. However, restricted animals had a decreased expression of PPARG.

The goal of this study was to investigate feedlot performance and meat quality of calves born to cows that underwent a nutrient restriction during the second trimester of gestation which may be occurring in the Intermountain West. Thirty-four angus influenced calves from the same sire were used for this study. The calves were born from cows that were separated into either a maintenance group, and kept on an irrigated pasture, or a restricted group, that was placed on an unirrigated pasture and allowed to lose one body condition score during the second trimester of pregnancy. This study begins with the calves on day 85 of the finishing portion of the feedlot phase. During the finishing feedlot phase, calves were individually housed, fed ad libitum, and feedlot performance measurements were taken every 28 days. Carcasses from the calves were evaluated for yield and quality. A loin from each carcass was collected, aged, frozen, and cut into individually packaged steaks that were used to assess meat quality. There was no difference in feedlot performance and carcass measurements for either maintenance and restricted calves. Meat quality measurements revealed no difference in color, instrumental tenderness values, or composition of steaks from either group. A trained sensory panel found that ten characteristics of flavor were similar for both treatments. There was however, a trend for steaks from nutrient restricted cattle to have more of a bloody/serumy flavor. The trained sensory panel also found that there was a difference in tenderness of steaks from nutrient restricted animals being perceived as more tender than animals from maintenance cows. The results of this study demonstrate that nutrient restriction during mid-gestation does not have negative effects on feedlot performance, carcass characteristics, or meat quality measurements. These results also indicate that steaks from calves born to nutrient restricted cows may be perceived as more tender.

Galactopoietic effects of somatotropin are the result of IGF-I and require high-quality nutrient intake. This study investigated short-term partitioning effects during recombinant bovine somatotropin (bST) administration in high yielding early lactation dairy cows. Administration of recombinant bST has been shown generally to alter results of metabolic tests in the face of unchanged basal glucose and insulin concentrations. Ten multiparous Holstein cows were subjected to rbST (Lactotropin®) and/or feed intake restriction to 80% of predicted ME requirement (80% ME). Responses to insulin challenge (0.1 IU porcine insulin/kg BW. 210 min) and hyperglycaemic clamp (+50 mg/dL whole blood, 120 min) were tested during weeks 8 (control), 9 (rbST ), 11 (80% ME) and 12 (rbST + 80% ME) postpartum. Plasma and whole blood samples were assayed for glucose concentrations. The rbST treatment decreased fasting whole-blood glucose concentration by 9.4% (P<0.0001), which was likely a remnant of control hyperglycaemia. Maximum glucose response was 4.0 mg/dL (21.7%) lower (P<0.0038) and took 6.5 minutes longer to attain (P<0.0037). Steady-state glucose infusion rate (SSGIR) decreased by 8.1 % (P<0.0001). The 80% ME treatment decreased glucose availability by 5 to 6% (P<0.0100), while no glucose responses were affected. Restricted energy intake during treatment with rbST resulted in plasma glucose increase by 5.5% (P<0.0001). Peripheral uptake and utilization of glucose increased by 5.1 % (P<0.0005). Compared to energy restriction, 80%ME + rbST did not alter effects of nutrient restriction on responses to exogenous insulin challenge. Effects were small and inconsistent. SSGIR decreased by 5.0% in the 80% ME + rbST compared to the 80% ME period (P<0.0004) and the change in the hyperglycaemic clamp in the absence of an effect in the insulin challenge may be due to differences in endogenous insulin secretion. The conclusion was that rbST treatment resulted in altered glucose metabolic responses, even with restricted energy intake. / Dissertation (MSc(Agric))--University of Pretoria, 2008. / Animal and Wildlife Sciences / unrestricted

Made available in DSpace on 2016-12-08T16:24:19Z (GMT). No. of bitstreams: 1 PGCA14MA151.pdf: 708869 bytes, checksum: b415f3969a32ace6d03f91e8e5e317b8 (MD5) Previous issue date: 2014-09-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to evaluate the recovery of LINA with diets that supply the requirements of energy, protein and both, as evaluating its effect about the milk production and composition, food intake, body weight and body condition score. The experiment was conducted in 3x3 Latin-square with three treatments and three experimental periods. Each experimental period lasted 24 days and consisted of three phases: adaptation (days 1-13), induction of milk instability to the alcohol test (13-17) and recovery of milk instability to the alcohol test (17-24). Twelve dairy cows Holstein and crossbreed Holstein x Jersey were divided into three homogeneous groups being fed only in the trough, with their diets formulated according to NRC (2001), and weighed before supplying, and eventual leftovers, evaluating the dry matter intake (DMI), crude protein (CP), total digestible nutrients (TDN) and neutral detergent fiber (NDF). Milk production was recorded at each milking and milk samples were collected to evaluate the stability of milk to the alcohol test, analysis of fat, protein, lactose, urea nitrogen concentration and somatic cell count (SCC). The data of phase of recovery of milk instability were submitted to analysis of variance and linear regression, using the MIXED and REG procedures of SAS statistical 14 15 package. The stability of milk to the alcohol test was affected by the treatments (P<0,0001), and the animals only reached the recovery of milk stability with the use of diets that supplied the requirements of energy and protein, with some recovery in diets that supplied only the energy requirements. Milk production was also higher with the use of diets that supplied the requirements of energy and protein, intermediate production with the use of diets that supplied only the energy requirement, and lower with the supplying of only protein requirements. The intakes of DM, CP, NDF and TDN were affected by diets for recovery of LINA (P<0,0001) and intake of DM, CP and TDN was higher in the treatment with diet that supplied the requirements of energy and protein, and NDF intake was higher in the treatment with diet that only supplied the energy requirement. Analyses of composition (fat, protein, lactose, urea nitrogen) were also affected by the treatments (P<0,0001), as well as body weight and body condition score (P<0,0001 and P=0,0002, respectively). It is conclude that the recovery of LINA is possible only with adequate levels of energy and protein in the diet / O objetivo do presente trabalho foi avaliar a recuperação de LINA com dietas que suprem as exigências de energia e/ou proteína, assim como seu efeito sobre a produção e composição do leite, consumo de alimentos, peso vivo e escore de condição corporal. O experimento foi desenvolvido em quadrado-latino 3x3, com três tratamentos e três períodos experimentais. Cada período experimental teve duração de 24 dias, sendo composto por três fases: adaptação (dias 1 a 13), indução da instabilidade do leite ao teste do álcool (dias 13 a dia 17) e recuperação da instabilidade do leite ao teste do álcool (dias 17 a 24). Doze vacas leiteiras Holandês e mestiças Holandês x Jersey foram divididas em três grupos homogêneos sendo alimentados somente no cocho, com suas dietas formuladas segundo o NRC (2001), sendo pesadas antes do fornecimento, bem como eventuais sobras, avaliando o consumo de matéria seca (MS), proteína bruta (PB), nutrientes digestíveis totais (NDT) e fibra em detergente neutro (FDN). A produção de leite foi registrada durante todas as ordenhas e amostras de leite foram coletadas para avaliar a estabilidade do leite ao teste do álcool, análise dos teores de gordura, proteína, lactose, nitrogênio uréico e contagem de células somáticas (CCS). Os dados da fase de recuperação da instabilidade do leite foram submetidos à análise de variância e regressão linear, utilizando-se os 10 11 procedimentos MIXED e REG do pacote estatístico SAS. A estabilidade do leite ao teste do álcool foi afetada pelos tratamentos (P<0,0001), sendo que os animais só atingiram recuperação da estabilidade do leite com a utilização de dietas que atendem as exigências, de energia e proteína, com alguma recuperação em dietas que atenderam as exigências de energia. A produção de leite também foi maior com a utilização de dietas que atenderam as exigências de energia e proteína, intermediária com dietas que atenderam somente a exigência de energia e menores com o fornecimento de dietas que atenderam somente as exigências de proteína. Os consumos de MS, PB, NDT e FDN foram afetados pelas dietas de recuperação de LINA (P<0,0001), sendo que o consumo de MS, PB e NDT foi maior no tratamento com dietas que atendem as exigências de energia e proteína, e consumo de FDN foi maior no tratamento com dieta que atende somente a exigência de energia. As análises de composição (gordura, proteína, lactose, nitrogênio uréico) também foram afetadas pelos tratamentos (P<0,0001), assim como o peso vivo e o escore de condição corporal (P<0,0001 e P=0,0002, respectivamente). Conclui-se que a recuperação de LINA somente é possível com níveis adequados de energia e proteína na dieta

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