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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Intake, Nutritive Value and Digestibility in Holstein Heifers Fed Diets Supplemented with Peanut Hay (Arachis Hypogeal L)

Phiri, Diniwe Grace 07 May 2016 (has links)
This study was conducted to measure the intake; nutritive value and digestibility of peanut hay (Arachis hypogaea L.). Fourteen Holstein heifers (BW= 408 plus/minus 32 kg; Age = 15.4 months plus/minus 0.5) were randomly allocated to two diets: peanut hay (PH) and corn silage (CS) adlibtum for 26 days. The PH consisted of 66:34 forage: concentrate (F:C) and CS diet contained 57:43 F:C ratio. Peanut hay at 91.8% DM contained 8% CP, 64% NDF, 51.9% ADF and 8 % ash. DMI and CP was not different across the treatment diets (P>0.05). NDF and ADF intake was different between the diets with PH being greater (P<0.01). Feed Efficiency using the feed to gain ratio was different across the diets (P<0.0001). Dry matter digestibility was 75.37% for CS diet and 68.53% for PH diet. Peanut hay basal diets formulated to contain low F:C ratio can increase growth in dairy heifers.
2

Effects of Forced Exercise on Fertility, Parturition, Mammary Edema, Feed Consumption, and Milk Production in Two-Year-Old Holstein Dairy Heifers

Barker, Brent O. 01 May 1976 (has links)
Forty-two springer Holstein heifers were grouped in threes by sire, body weight, and due date. One of each group served as a control (no exercise). One of each group was exercised at 5.5 kilometers per hour for 1.6 kilometers per day, 5 days per week beginning 4 weeks before expected calving date . The third member of each group was exercised the same as the second member, but exercise was continued for 10 days after calving. Exercise was in a circular lane with a motor driven gate. Prepartum exercise increased ease of parturition and reduced the length of time from calving to release of the placenta. Exercise resulted in smaller uterine horn diameters at 42 days postpartum, but had no significant effect on measures of fertility such as days open or services per conception . Exercise did not appear to reduce severity of udder edema, but edema was first noticeable in control heifers. Milk production for the first 50 days after calving showed no affect from prepartum exercise, but continuing exercise after calving reduced milk production 2.4 kg per day (P< .05). Grain was fed according to production, hence grain consumption was also significantly lower for the postpartum exercise group. Hay consumption for the prepartum exercise group was significantly lower than for controls. Prepartum exercise significantly increased feed utilization efficiency as compared to postpartum exercise.
3

Ganho de Peso de Novilhas Mesti?as Leiteiras Submetidas ou N?o ? Restri??o Alimentar Antes do Per?odo Seco / Compensatory Growth of Crossbred heifers (Holstein-zebu) Fed a Proteic-energetic Supplement in the Dry Season

Valente, Tiago Neves Pereira 31 July 2006 (has links)
Made available in DSpace on 2016-04-28T14:59:41Z (GMT). No. of bitstreams: 1 2006-Tiago Neves Pereira Valente.pdf: 399035 bytes, checksum: 03083e58f68f730df2aa96f8f9ff5034 (MD5) Previous issue date: 2006-07-31 / This study was carried out on the Serop?dica Experimental Station of Pesagro, Rio de Janeiro, Brazil, from April 7 to October 6 of 2005 (182 days of dry season) and utilized two groups of 11 dairy heifers (Holstein/Zebu) weighting 177,6?6 kg and 15,7?4 months age. In the pre-experimental period, for 49 days (April 7 to May 26), 11 heifers were mantained closed into a stall and submitted to a forced restriction in their daily dry matter intake which resulted in small lost of body weight (-2,9 kg in relation of initial weight) and others 11 heifers were mantained free on the pasture and gained 30,2 kg in relation to their initial weight. After this pre-experimental period, both groups were kept on the same grazing area and received a proteic-energetic supplement containing 30% urea, 30% NaCl and 40% of wheat middlings. Both groups were weighted at each 21 days; on the same data, only the group that suffered forced alimentary restriction was evaluated for their body condiction score (BCS). The animals that suffered an alimentary restriction had higher daily weight gain troughout the dry season. At the end of the experimental period the difference between the two groups was 15,6 kg. The values for body condiction score were different in the period of lost of body weight and in the re-growth phase; i.e. for a lost of 14,3 kg of body weigth the heifers had 0,68 units in their BCS and for a gain of 48,2 kg of body weigth, during the proteic-energetic supplementary phase, the same heifers had + 0,31 units of BCS. / O experimento foi realizado na ?rea de bovinos leiteiros da Esta??o Experimental de Serop?dica (EES) da Pesagro-Rio com dura??o de 182 dias de 07/04/05 a 06/10/05. Foram utilizadas 22 novilhas mesti?as leiteiras (Holand?s-Zebu), com idade de 15,7?4 meses e peso m?dio de 177,6?6 kg no in?cio do experimento, o objetivo foi avaliar o ganho de peso das novilhas que passaram por restri??o alimentar antes do per?odo seco e a utiliza??o de um suplemento prot?ico-energ?tico durante o per?odo de estiagem. A ?rea foi dividida em dois piquetes de tamanho similar formados por pastagens naturais de grama batatais (Paspalum notatum) e capim bel?m (Sporobulus poiretii), foram vedados 50 dias antes do in?cio do experimento, e os animais manejados em regime de pastejo cont?nuo. O per?odo pr?-experimental teve dura??o de 49 dias e um lote de onze novilhas permaneceu preso no curral com alimenta??o volumosa limitada, esta restri??o alimentar gerou uma diferen?a entre os dois lotes de 31,5 kg no in?cio do experimento. O lote controle permaneceu mantido no pasto. Ap?s o per?odo de restri??o alimentar os dois lotes foram mantidos nos piquetes e receberam um suplemento prot?ico-energ?tico que continha 30% de ur?ia, 30% NaCl e 40% de farelo de trigo. Juntamente com as pesagens a cada 21 dias, notas para escore corporal foram dadas aos animais de ambos os lotes. As novilhas que foram submetidas ? restri??o alimentar antes do per?odo seco tiveram um ganho de peso superior ao lote controle durante a esta??o seca, indicando que um poss?vel crescimento compensat?rio, mesmo no per?odo desfavor?vel do ano. Na pesagem ap?s 69 dias do final da suplementa??o verificou-se que a diferen?a de peso foi reduzida de 15,6 kg ao final da suplementa??o prot?ico-energ?tica para 13,5 kg. Os escores corporais foram diferentes para o emagrecimento e engorda.
4

Chromosome Abnormalities as a possible Cause of Reduced Fertility in Dairy Heifers

Henderson, Stanley L. 01 May 1990 (has links)
Chromosome evaluations were made on leukocyte blood samples from 169 phenotypically normal nulliparous Holstein heifers. These were from three different reproduction groups collected in sets of threes from 10 different herds in the western United States. Group 1, the control group, consisted of heifers diagnosed pregnant after one or two breedings; Group 2 consisted of heifers diagnosed pregnant after three or four breedings; and Group 3 consisted of heifers diagnosed open after four or more breedings. Metaphase chromosome spreads used in these analyses were obtained through 72-hour leukocyte cultures from heparinized whole blood. Processed cells were dropped onto a slide, air-dried, and stained with Giemsa. Chromosomes were then counted and X chromosomes were identified. A total of 1, 597 cells was evaluated, with 1,439 cells having counts of 60 chromosomes each. Thirty cells had less than 58 chromosomes, 31 cells had 58 chromosomes, 75 cells had 59 chromosomes, 14 cells had 61 chromosomes, and 8 cells had more than 61 chromosomes (9 .98% were different than 60). All counts of other than 60 chromosomes were isolated cases and were not identified as abnormalities. Only two cells from two separate heifers contained what may have been sex chromosome abnormalities. No persistent chromosomal defects were observed among the 169 heifers.
5

A Comparison of Three Estrous Detection Management Schemes for Dairy Heifers

Lagerstedt, Ann 01 May 1990 (has links)
Heifers should represent the greatest genetic potential within a dairy herd. To maximize this potential, heifers must be inseminated to proven sires, a practice requiring management changes on many dairies. Holstein heifers (n=115) were allotted to one of three groups to compare alternatives to daily estrous detection that may facilitate the management of a program of artificial insemination for heifers. Group 1 heifers (Controls) received no treatment but were observed twice daily for signs of estrus. Group 2 heifers (2X-PGF) were synchronized with two injections of prostaglandin F2 alpha given 11 days apart and observed for estrus. Group 3 heifers (MGA+PGF) were synchronized with 9 days of melengestrol acetate feeding and an injection of prostaglandin F2 alpha 14 days after the last feeding and observed for estrus. Comparisons were made on the effectiveness of each treatment in estrous response and pregnancy rates and on the management requirements and economics associated with each program. Estrous response was significantly higher for the 2X-PGF group, while synchronized pregnancy and first-service conception rates did not differ. On an annual basis, the MGA+PGF group was calculated to require three-quarters of the labor input as compared to the 2X-PGF group and less than a fifth of the labor required for the Control group. A program of daily estrous detection was calculated to have an economic advantage over synchronization the frequency estrous synchronization programs was scheduled four times per year. was increased to six times per when When year, synchronization had a slight economic advantage over daily estrous detection when animal numbers were low and labor costs were high. The economic advantage of daily estrous detection is reduced when synchronization is performed more frequently throughout the year.
6

Efeitos da restrição alimentar e da somatotropina bovina recombinante sobre parâmetros do metabolismo energético, protéico, enzimático e mineral de novilhas leiteiras no pré-parto / Effect of feed restriction and of recombinant bovine somatotropin on energetic, proteic, enzymatic and mineral metabolic parameters of prepartum dairy heifers

Goulart, Maikel Alan 02 April 2009 (has links)
Made available in DSpace on 2014-08-20T14:37:57Z (GMT). No. of bitstreams: 1 dissertacao_maikel_alan_goulart.pdf: 244034 bytes, checksum: 458e594d86ecd076dc3f12b7d9e46913 (MD5) Previous issue date: 2009-04-02 / The aim of this study was to evaluate the effects of feed restriction and of recombinant bovine somatotropin (bST) on energetic, proteic, enzymatic and mineral metabolic parameters of prepartum dairy heifers. Forty four pregnant heifers were used for this study. The experimental period ranged from 35 days prepartum to partum and from 60 days to 160 postpartum. These heifers were divided in four groups with 11 animals each: Control+bST: fed to allow 100% of the dry matter intake (DMI) plus bST injections; Restriction+bST: fed to allow 80% of the DMI plus bST injection; Control: fed to allow 100% of the DMI plus placebo injections and Restriction: fed to allow 80% of the DMI plus placebo injections. The heifers receive three injections in the prepartum period 14 days apart. Measurements of body condition score, weight, productive and reproductive performance were conducted during pre and postpartum periods, while blood parameters were measured only in the prepartum period. Glucose concentrations were higher (P<0.05) in the Control+bST groups compared to Control and Restriction groups, while urea concentrations were higher in Restriction group compared to Control and Control+bST. Non-esterified fatty acids concentrations were higher (P<0.05) for Restriction group compared to Control and Control+bST groups. There was not observed difference (P > 0.05) in the concentrations of calcium (Ca), phosphorus (P), Ca:P ratio, ketone bodies and liver enzymes, aspartate aminotransferase (AST) and gamma glutamil transferase (GGT) between groups. Regarding performance evaluations, no difference was observed for calf weight at birth, retention of fetal membranes, body condition score and reproductive performance, but a tendency (P = 0.06) to higher production in the Control+bST group compared to restriction group was observed. These results shown that prepatum management, including feed restriction and bST injection, could be efficient to allow metabolic and physiologic adaptation to the postpartum period. / O objetivo deste estudo foi determinar os efeitos da restrição alimentar e da somatotropina bovina recombinante (bST) sobre parâmetros do metabolismo energético, protéico, enzimáticos e mineral de novilhas leiteiras no pré-parto. Foram utilizadas no experimento 44 novilhas prenhes da raça holandês. O período experimental variou de 35 dias do pré-parto até o parto e dos 60 até 160 dias pós-parto. Estas novilhas foram divididas em 4 tratamentos com 11 animais cada: Controle+bST: alimentadas com 100% da ingestão de matéria seca (IMS) com aplicações de bST; Restrição+bST - alimentadas com 80% da IMS com aplicações de bST; Controle: alimentadas com 100% da IMS com aplicações de placebo; Restrição: alimentadas com 80% da IMS com aplicações de placebo. Foram realizadas no período pré-parto 3 aplicações de bST ou placebo a cada 14 dias. Realizaram-se avaliações de escore de condição corporal, peso ao nascer dos neonatos e desempenho produtivo e reprodutivo durante o pré e pós-parto e determinações dos parâmetros metabólicos energético, protéico, mineral e enzimático, somente no período pré-parto das novilhas. Os níveis de glucose foram maiores (P<0,05) para o grupo Controle+bST, comparado aos Grupos Controle e Restrição. Quanto aos níveis de ácidos graxos não esterificados, estes foram maiores (P<0,05) para o grupo Restrição+bST em comparação aos grupos Controle e Controle+bST. Em relação aos níveis de uréia, estes foram superiores (p<0,05) para o grupo Restrição comparado ao Controle e Controle+bST. Não foram observadas diferenças (P>0,05) entre os grupos experimentais quanto aos metabólitos, cálcio (Ca), fósforo (P), a relação Ca:P e corpos cetônicos, além das enzimas hepáticas, aspartato aminotransferase (AST) e gama-glutamiltransferase (GGT). Em relação às avaliações zootécnicas não foram observadas diferenças (P>0,05) entre os grupos quanto as variáveis, peso ao nascer dos neonatos, retenção de placenta, escore de condição corporal e desempenho reprodutivo, sendo observado tendências (P=0,06) de maior produção leiteira para vacas do grupo Controle+bST em comparação a vacas do grupo Restrição. Estes resultados demonstraram que as estratégias adotadas no pré-parto, utilizando a restrição alimentar e a administração de bST em novilhas leiteiras, podem ser eficientes na adaptação metabólica e fisiológica para o período pós-parto destes animas.
7

Desempenho de novilhas leiteiras alimentadas com diferentes volumosos / Performance of dairy heifers fed with different forages

Burgos, Eusebio Manuel Galindo 24 July 2013 (has links)
Made available in DSpace on 2015-03-26T13:55:20Z (GMT). No. of bitstreams: 1 texto completo.pdf: 562262 bytes, checksum: 3877ee62b4d2fbbf059feb8b198e8118 (MD5) Previous issue date: 2013-07-24 / This study aimed to evaluate the effects of different forages on intake, digestibility and performance of dairy heifers. Sixteen dairy heifers were used, and they had initial body weight of 150 ± 19 kg and 8 mo. The animals were divided into a randomized block design with four replications, where each animal was used as experimental unit and blocks formed in accordance with the initial body weight of the animals. They were fed for 70 days. Four sources of roughage were used: corn silage (CS), sorghum silage (SS), sugar cane in nature (SC) sugar cane silage (SCS). The amounts of concentrate were fixed at 0.5% of body weight (BW) for CS and SS, 0.7% BW for SC, and 1.0% BW for SSC. The animals fed diets based on CS and SS had higher average daily gain than those fed with diets containing SC and SCS. Intake and digestibility of dry matter (DM), organic matter (OM) and metabolizable energy (ME) were higher for heifers fed CS and SS. There were differences in intake and digestibility of crude protein (CP) and neutral detergent fiber (NDF) for heifers fed SS. For non-fiber carbohydrates (NFC), there were greater intake and digestibility in heifers fed on CS. There were no diet effect for withers height and body length. There was an effect of CS and SS for chest girth. It is concluded that diets based on corn silage and sorghum silage offer higher performance than diets based on sugar cane in nature or sugar cane silage for dairy heifers. / Objetivou-se avaliar os efeitos de diferentes volumosos sobre o consumo, digestibilidade e desempenho de novilhas leiteiras. Foram utilizadas dezesseis novilhas leiteiras da raça Holandesa, com peso médio inicial 150 ± 19 kg e idade media 8 meses, distribuídas em delineamento em blocos casualizados, com quatro repetições, sendo cada animal considerado uma unidade experimental e os blocos formados com base ao peso inicial dos animais, durante 70 dias. Os tratamentos constituíram de quatro volumosos: silagem de milho (SM), silagem de sorgo (SS), cana-de-açúcar in natura (CN) e silagem de cana-de-açúcar (SC). As dietas foram formuladas fixando a quantidade de concentrado em 0,5% do peso corporal para silagens de milho e sorgo, 0,7% para cana-de-açúcar in natura e 1,0% para silagem de cana-de-açúcar. Os animais alimentados com dietas à base de silagens de milho e sorgo apresentaram maior ganho médio diário em relação aos alimentados com dietas contendo cana-de-açúcar in natura e silagem de cana-de-açúcar. O consumo e a digestibilidade de matéria seca (MS), matéria orgânica (MO) e energia digestível (ED) foram maiores para as novilhas alimentadas com dietas à base de silagens de milho e de sorgo. Houve maior consumo e digestibilidade de proteína bruta (PB) e fibra em detergente neutro (FDN) para as novilhas alimentadas à base de silagem de sorgo. Para carboidratos não-fibrosos (CNF), verificou-se maior consumo e digestibilidade nas novilhas alimentadas à base de silagem de milho. Não foi observado efeito sobre os parâmetros de altura de cernelha e comprimento corporal. Houve maior ganho de perímetro torácico para as novilhas alimentadas com dietas a base de silagens de milho e de sorgo. Conclui-se que dietas à base de silagens de milho ou sorgo proporcionam maiores desempenhos do que dietas à base de cana-de-açúcar in natura ou ensilada para as novilhas leiteiras.

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