Animal traits differ not only in mean, but also in variation around the mean. For instance, one sire’s daughter group may be very homogeneous, while another sire’s daughters are much more heterogeneous in performance. The difference in residual variance can partially be explained by genetic differences. Models for such genetic heterogeneity of environmental variance include genetic effects for the mean and residual variance, and a correlation between the genetic effects for the mean and residual variance to measure how the residual variance might vary with the mean. The aim of this thesis was to develop a method based on double hierarchical generalized linear models for estimating genetic heteroscedasticity, and to apply it on four traits in two domestic animal species; teat count and litter size in pigs, and milk production and somatic cell count in dairy cows. The method developed is fast and has been implemented in software that is widely used in animal breeding, which makes it convenient to use. It is based on an approximation of double hierarchical generalized linear models by normal distributions. When having repeated observations on individuals or genetic groups, the estimates were found to be unbiased. For the traits studied, the estimated heritability values for the mean and the residual variance, and the genetic coefficients of variation, were found in the usual ranges reported. The genetic correlation between mean and residual variance was estimated for the pig traits only, and was found to be favorable for litter size, but unfavorable for teat count.

Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Profitable milk production and genetic improvement in dairy herds are largely dependant on fertile cows capable of calving down on an annual basis. Several studies indicate declines in the reproductive performance of Holstein cows over the last 30 years. Calving interval (CI) and services per conception (SPC) are being used by dairy farmers as indicators of the reproductive performance of dairy cows. However, using these traits as cow fertility indicators is problematic as CI is dependent on subsequent calving dates while SPC is strongly linked to inseminator proficiency. The aim of the study is therefore, firstly, to describe alternative fertility traits derived from insemination and calving dates and pregnancy check results. The effects of some non-genetic factors on these traits are discussed. Means±sd for interval traits from calving to first insemination (CFS) and the interval from calving to conception (DO) were respectively 77±30 and 134±74 days while the number of services per conception (SPC) averaged 2.55±1.79. The percentage of first servics occurring within 80 days post-partum (FS80d) and the proportion of cows being confirmed pregnant within 100 (PD100d) and 200 days post-partum (PD200d) were 0.64±0.48, 0.36±0.48 and 0.71±0.45, respectively. Although fertility traits were affected significantly by lactation number, calving year and month, herds (managers) had the largest effect. Fertility is a complex trait, however, the challenge is finding traits that best describe this trait. Genetic parameters for these traits could give an indication of the response to selection in dairy herds. In the second part of this study, genetic parameters and correlations between fertility traits, sourced from standard reproduction management data bases, are analysed for Holstein cows using bivariate linearlinear and linear-threshold animal models. Insemination events (n = 69 181) from 26 645 lactations of 9 046 Holstein cows from 14 herds, calving down during the period from 1991 to 2007, were available. The outcome of each AI event was known. Insemination records were linked to the calving date of each cow, lactation number as well as dam and sire identification. Fertility traits indicating the ability of cows to show heat early in the breeding period, and to become pregnant, were derived. Data were analysed using bivariate linear-linear and linear-threshold animal models with fixed effects being herd (14 levels), year (17 levels), season (4 levels) and lactation number (6 levels). The model included the random effects of animal and animal permanent environment (PE). Heritability estimates ranged from 0.04±0.01 to 0.10±0.02 for FS80d, from 0.07±0.01 to 0.08±0.02 for PD100d and from 0.06±0.04 to 0.08±0.02 for PD200d depending on the two-trait combination. Although heritability estimates of most fertility traits were below 0.10, they were in close agreement with results published by other researchers using linear models. Genetic correlations between different fertility parameters analyzed in this study indicated that it is unlikely that a single characteristic would serve well for selection purposes; instead, combining different traits could be used in selection programmes to improve fertility. Further research in constructing an optimal fertility index is warranted. In the third part of this study, genetic parameters for South African Holstein cows for fertility and production traits were estimated from 2415 lactation records. Two-trait analysis of fertility and milk yield was investigated as a method to estimate fertility breeding values when culling, or selection based on milk yield in early lactation, determines presence or absence of fertility observations in later lactations. Fertility traits were days from calving to first service (CFS), days from calving to conception (DO), percentage cows inseminated within 80d post-partum (FS80d), number of service per conception (SPC), and the binary traits percentage of cows pregnant within 100d and 200d postpartum (PD100d, Pd200d). Milk production traits were 300 day milk, fat and protein yield. For fertility traits, range of estimates of heritability (h2) was 0.006 to 0.08 for linear traits and 0.05 to 0.12 for binary traits. The range for permanent environmental variance (c2) was 0.016 to 0.032. In this study genetic correlations of fertility with milk production traits were unfavourable ranging between −0.93 to 0.76. / AFRIKAANSE OPSOMMING: Winsgewende melkproduksie en genetiese verbetering in melkkuddes hang grootliks af van vrugbare koeie wat op ‘n jaarlikse basis kalf. Verskeie studies toon dat die reproduksievermoë van Holsteinkoeie oor die afgelope 30 jaar afgeneem het. Melkboere gebruik tussenkalfperiode (TKP) en aantal inseminasies per konsepsie (KIPK) as aanduidings van die reproduksievermoë van melkkoeie. Dit is egter moeilik om hierdie eienskappe as vrugbaarheidseienskappe vir melkkoeie te gebruik omdat TKP afhanklik is van opeenvolgende kalfdatums terwyl KIPK baie sterk gekoppel is aan die inseminasievermoë van die insemineerders. In die eerste gedeelte van die studie word alternatiewe vrugbaarheidseienskappe, wat afgelei is van inseminasie- en kalfdatums en die uitslag van dragtigheidsondersoeke, beskryf. Die invloed van ‘n aantal nie-genetiese faktore op dié eienskappe word ook bespreek. Gemiddeldes±standaard afwykings vir die periode vanaf kalwing tot eerste inseminasie (CFS), die periode van kalwing tot konsepsie (DO) was 77±30 en 134±74 dae onderskeidelik, terwyl die aantal inseminasies per konsepsie (SPC) 2.55±1.79 was. Die persentasie eerste inseminasies wat binne 80 dae na kalwing (FS80d), en die persentasie koeie wat dragtig bevestig is binne 100 (PD100d) en 200 dae na kalwing (PD200d) was 0.64±0.48, 0.36±0.48 en 0.71±0.45, onderskeidelik. Hoewel vrugbaarheidseienskappe betekenisvol beïnvloed is deur laktasienommer, jaar en seisoen van kalwing, het kuddes (bestuurders) die grootste effek op eienskappe gehad. Vrugbaarheid is ‘n ingewikkelde eienskap en die uitdaging is om eienskappe te vind wat dit die beste beskryf. Genetiese parameters vir eienskappe wat oorweeg word sal ‘n aanduiding gee van die seleksieresponse in melkkuddes. In die tweede gedeelte van die studie is genetiese parameters van vrugbaarheidseienskappe en korrelasies tussen dié eienskappe beraam. Eienskappe is bekom vanaf reproduksiebestuursprogramme wat in melkkuddes gebruik word. Al die inseminasierekords (n = 69 181) van 26 645 laktasies van 9 046 Holsteinkoeie van 14 melkkuddes wat tussen 1991 en 2007 gekalf het, was beskikbaar. Die uitslag van elke inseminasie was bekend. Inseminasierekords is met die kalfdatum, laktasienommer, identifkasienommers van die moeder en vader van elke koei, gekoppel. Vrugbaarheidseienskappe wat die vermoë van koeie aandui om vroeg na kalwing op hitte te kom en beset te raak, is verkry. Die data is ontleed deur gebruik te maak van twee-eienskap liniêreliniêr- en liniêr-drempel-diere modelle met vaste effekte kudde (14 vlakke), jaar (17 vlakke), siesoen (4 vlakke) en laktasienommer (6 vlakke). Die modelle het die ewekansige effekte van dier- en dierpermananente omgewingseffkte (PE) ingesluit. Genetiese, diere PE en residuele korrelasies is vervolgens beraam. Oorerflikhede varieer vanaf 0.04±0.01 tot 0.10±0.02 vir FS80d, vanaf 0.07±0.01 tot 0.08±0.02 vir PD100d en vanaf 0.06±0.04 tot 0.08±0.02 vir PD200d, afhangende van die tweeeienskap kombinasie. Ten spyte daarvan dat die oorerflikhede van die meeste vrugbaarseienskappe laer as 0.10 is, is die resultate in ooreenstemming met ander navorsers wat liniëre modelle gebruik het. Genetiese korrelasies tussen verskillende vrugbaarheidseienskappe toon dat daar nie enkel beste eienskap is wat vir seleksiedoeleindes gebruik kan word nie. Dit sou waarskynlik beter wees om verskillende eienskappe te kombineer om die vrugbaarheid in melkkoeie te verbeter. Verdere navorsing is nodig om ‘n optimale vrugbaarheidseienskap te ontwikkel. Dit is belangrik dat die verband tussen reproduksie en melkproduksie vir melkkoeie bepaal word. In die derde gedeelte van die studie is genetiese parameters vir vrugbaarheid- en melkproduksieeienskappe vir Suid Afrikaanse Holsteinkoeie beraam. ‘n Totaal van 2415 laktasierekords was beskikbaar. Vrugbaarheid en melkproduksie is volgens ‘n twee-eienskap analise ontleed as ‘n metode om teelwaardes vir vrugbaarheid te bepaal in gevalle waar die uitskot of seleksie gebaseer op melkproduksie in vroeglaktasie die teenwoordigheid of afwesigheid van vrugbaarheidseienskappe in latere laktasies bepaal. Vrugbaarheidseienskappe was die periode (aantal dae) tussen kalfdatum en eerste inseminasie (CFS), die aantal dae van kalf tot konsepsie (DO), die persentasie koeie wat by 80 dae na kalf vir die eerste keer geïnsemineer was (FS80d), die aantal inseminasies per konsepsie (SPC), en binêre eienskappe van die persentasie koeie wat by 100 dae en 200 dae na kalf beset was (PD100d en PD200d). Melkproduksie-eienskappe was 300-dae melk., vet- en proteïnproduksie. Vir vrugbaarheidseienskappe het die oorerflikheidswaardes (h2) vanaf 0.006 tot 0.08 vir liniêre eienskappe gevarieer en tussen 0.05 tot 0.12 vir binêre eienskappe. Die permanente omgewingsvariansie (c2) het tussen 0.016 tot 0.032 gevarieer. In hierdie studie was die genetiese korrelasies tussen vrugbaarheidseienskappe en melkproduksie-eienskappe ongunstig en het dit tussen −0.93 tot 0.76 gevarieer.

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The aim of this study was to determine the rate of transfer of melamine as fertilizer ingredient to kikuyu pastures and if melamine would be transferred from the fertilized pasture to cow’s milk. Three trials were conducted in the study, viz. a pilot pot plant trial, an applied pasture trial and a milk production trial. Melamine is a commercially available industrial chemical with a high nitrogen content. Large quantities of melamine waste can sometimes be incorporated into crop and pasture fertilizers due to the high N content. An initial pot plant trial with kikuyu was conducted to determine whether melamine would be absorbed as such from the soil to the plant material. The pots were fertilized in the form of melamine adulterated Chinese maize Gluten 60, at a rate equivalent to 8.8 kg of melamine/ha. Results indicated that melamine was indeed absorbed and 7 days after fertilization, the concentration of melamine in the grass was 228 mg/kg. An applied pasture trial was then conducted were three pastures of 0.3 ha each were used. One pasture served as a control and received N fertilization in the form of LAN at a rate of 40 kg N/ha. The other two pastures also received LAN, but with 10% (Treatment 1) and 20% (Treatment 2) of the LAN-N substituted with melamine-N. All three pastures also received P-fertilization in the form of Single Superphosphate at a rate of 20 kg P/ha and KCl fertilizer at a rate of 50 kg K/ha. Pasture samples were taken once a week for 10 weeks, each time at the exact same spot in each camp. Samples were dried and finely milled before analysis via LC-MS/MS for melamine content. The initial concentration of melamine in the grass of Treatment 2 was higher than that in the grass of Treatment 1. The rate at which melamine decayed in the plant material was found to be quite similar for the two melamine treatments. In this trial, melamine took around 10 weeks to reach undetectable levels in the grass. It was concluded that melamine was absorbed as such from the soil by pasture grass when included in a fertilizer. For the milk production study, eighteen lactating Holstein cows, 60 ± 5.1 (SE) DIM, with a daily milk production of 36.5 ± 2.0 (SE) kg/d and weighing 609 ± 12.8 (SE) kg, were stratified according to milk production and then randomly allocated to three groups of six cows. The groups were then randomly allocated to the three pastures used in the applied pasture trial. Cows were kept on the melamine fertilized pasture for 9 days, in which they were allowed to graze the pasture for approximately 10 hours each day. After the 9 day period, melamine was withdrawn by placing the cows on the control pasture that did not receive melamine contaminated fertilization for another 7 days. During these 16 days, milk was collected twice a day, viz. during the morning and afternoon milkings. Milk samples of each cow were sub-divided into two samples, one was preserved with potassium dichromate and analysed for milk composition and the other was frozen until analysed for melamine by LC-MS/MS. For the duration of the trial, melamine containing milk was destroyed in order to prevent it from contaminating milk collected from the rest of the herd. Results from the analysis for melamine confirmed that melamine was transferred from melamine fertilized pasture to milk. In this study, it took 6 days from melamine withdrawal for melamine to reach undetectable levels in the milk. It was also found that the melamine fertilized pasture did not have any significant effect on the average milk production and milk composition of the cows. The aim of the study was met and it was confirmed that melamine can be transferred from fertilizer to the soil, to the pasture and to the milk of cows grazing these pastures. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die tempo van oordrag van melamien as bemestingstof na Kikuyu weiding te bepaal, asook om te bepaal of melamien oorgedra sal word vanaf die bemeste weiding na melk. Drie proewe is uitgevoer wat ‘n potplant loodsproef, ‘n toegepaste weidings proef en ‘n melkproduksie proef ingesluit het. Melamien is ʼn kommersieël-beskikbare industriële chemikalieë met ʼn hoë stikstof inhoud. Groot hoeveelhede van melamien-afval kan soms in kunsmis ingesluit word vir die bemesting van gewasse en weidings, weens die hoë stikstof inhoud van melamien. ʼn Potplant loodsproef met Kikuyu is uitgevoer om te bepaal of melamien vanaf die grond deur die plantmateriaal geabsorbeer word. Melamienbemesting is in die vorm van vervalste Chinese mieliegluten 60 toegedien teen ʼn hoeveelheid gelykstaande aan 8.8 kg melamien/ha. Die resultate van hierdie proef het getoon dat melamien wel deur die plantmateriaal geabsorbeer is en 7 dae nadat bemesting toegedien is, was die konsentrasie van melamien in die gras 228 of mg/kg. ʼn Toegepaste weidingstudie is uitgevoer waar drie kampe van 0.3 ha elk gebruik is. Een van die kampe het as ʼn kontrole gedien en het stikstof bemesting in die vorm van KAN teen 40 kg N/ha ontvang. Die ander twee kampe het KAN bemesting ontvang waar 10% (Behandeling 1) en 20% (Behandeling 2) van die KAN-N deur melamien-N vervang is. Al drie kampe het ook fosfaatbemesting in die vorm van Enkel Superfosfaat ontvang teen 20 kg P/ha, asook KCl kunsmis teen 50 kg K/ha. Weidingmonsters is eenmaal per week op dieselfde plek in elke kamp geneem vir 10 weke nadat bemesting toegedien is geneem. Monsters is gedroog en daarna fyngemaal voordat dit vir melamieninhoud geanaliseer is met behulp van LC-MS/MS. Die aanvanklike melamienkonsentrasie in die gras van Behandeling 2 was hoër as die in die gras van Behandeling 1. Die tempo waarteen die melamienkonsentrasie in die plant materiaal afgeneem het, was baie dieselfde vir Behandelings 1 en Behandeling 2. Dit het ongeveer 10 weke geneem voordat die melamien in die gras nie-waarneembare vlakke bereik het. Die gevolgtrekking is gemaak dat melamien wat in die vorm van kunsmis toegedien word, as sodanig uit die grond geabsorbeer word deur die gras. Vir die melkproduksiestudie is agtien lakterede Holsteinkoeie, 60 ± 5.1 (SE) dae in melk, met ‘n daaglikse melkproduksie van 36.5 ± 2.0 (SE) kg/dag en ‘n liggaamsmassa van 609 ± 12.8 (SE) kg, volgens hul melkproduksie gerangskik en ewekansig in drie groepe van ses koeie elk ingedeel. Die groepe is daarna ewekansig aan die drie kampe, wat in die toegepaste weidingstudie gebruik is toegedien. Die koeie is vir 9 dae op die melamienbemeste weidings gehou, waartydens hulle toegelaat is om vir ongeveer 10 ure elke dag te wei. Na die tydperk van 9 d, is die koeie vanaf die melamienbemeste weidings onttrek deur hulle op die kontroleweiding te plaas vir ʼn verdere 7 dae. Gedurende hierdie 16 dae is melkmonsters tweekeer per dag geneem, tydens die oggend- en die middagmelkings. Die melkmonsters van elke koei is vervolgens onderverdeel in twee monsters, waarvan een met kaliumdichromaat gepreserveer is vir die beplaing van melksamestelling, terwyl die ander een gevries is totdat dit later vir melamien inhoud ontleed is met behulp van LC-MS/MS. Melk van die koeie wat op die melamienweidings gewei het, is weggegooi om te voorkom dat melk van die res van die kudde gekontamineer kon word. Die resultate van die melamienanalises het getoon dat melamien oorgedra word vanaf die melamienbemeste weiding na die melk. Tydens hierdie studie het dit 6 dae geneem vandat koeie vanaf die melamienbemeste weidings onttrek is, totdat die melkmelamien nie-bepaalbare vlakke bereik het. Daar is bevind dat melamienbemeste weidings geen betekenisvolle uitwerking op die gemiddelde produksie en samestelling van die melk gehad het nie. Die doel van hierdie studie is bereik en daar is getoon dat melamien vanaf kunsmis na die grond, na die gras en na die melk oorgedra kan word wanneer koeie op weidings geplaas word wat melamienbemeste kunsmis ontvang het.

The aim of this diploma thesis was to analyze milk performance in two centers of Cooperative farm Rodvínov (in Zdešov and in Bednárec) and to find out the level of milk performance in different breeding conditions. The analysis was divided into two parts. Analysis No. 1 was comparing two centers of the farm with different breeding environment in 2012-2015. In Zdešov, the cows were reared in cubicle sheds (capacity 500 cows) and were milked twice a day in 2 x 12 herringbone milking parlor. In Bednárec, dairy cows were reared in an older cubicle shed K96 and K64 (capacity 160 cows), on straw bedding., and grazing during the grazing season and milking twice a day in 2 x 6 tandem parlor. In Bednárec, dairy cows achieved better results in the milk performance, in the fatness of milk, production of fat and protein. A statistically significant difference was confirmed in content ( = 0.001; p 0.001) and fat production ( = 0.05; p < 0.05) in a favor of dairy cows in Bednárec. A statistically significant difference was also confirmed in the milk performance of the same breeding groups reared in the different environment. Analysis No. 2 was monitoring the milk performance of dairy cows in Bednárec between years 2015 to 2018, divided in two periods. Period A - without change of breeding environment and period B - with changes in breeding environment and animal welfare. The first change was the movement of the dairy cows to the year-round pasture run. The second change was the commissioning of the new 2 x 12 side by side milking parlor and final movement to a new modern large-capacity stable (capacity 312 cows). There was no significant difference in the average milk performance of dairy cows depending on the change of breeding environment. During the changes, there was a statistically significant extension of the between calving period and the extension of the 1st calving age. Effect of stress caused by the environment and wellfare changes wasn't statistically significant for the level of milk performance of dairy cows. For the level of milk performance was more important the quality level of breeding management, finding cows in heat and insemination during the period of changes.

Orientador: Guilherme de Paula Nogueira / Resumo: O objetivo desse estudo foi comparar as concentrações séricas de cálcio, progesterona e fator de crescimento semelhante à insulina tipo 1 (IGF-I) e a ocorrência de crescimento microbiano no leite e de retenção de placenta antes da secagem e após o parto de vacas de alta produção tratadas ou não com cabergolina. Foram utilizadas 48 vacas multíparas, das raças holandesas, girolandas ou jersolandas no final da lactação (aproximadamente 60 dias antes do parto), com produção acima de 14 L/dia. Os animais foram divididos em grupo controle e grupo tratado, recebendo 5,6 mg de cabergolina via I.M. As coletas de sangue para mensuração das concentrações de progesterona, IGF-I e de cálcio sérico foram realizadas no dia da secagem (antes da aplicação da cabergolina), um dia após a secagem, sete dias após a secagem, de quinze a sete dias antes do parto e sete dias após o parto; no dia do parto e um dia após o parto foi feita apenas a dosagem de cálcio. Para análise microbiológica foi coletado leite sete dias antes da secagem, no dia da secagem e no dia do parto e foi observada a ocorência de retenção de placenta. Não foi observada diferença significativa entre os grupos (p > 0,05) na ocorrência de infecção da glândula mamária, nas concentrações séricas de cálcio e hormônios, exceto nas amostras coletadas uma semana após o parto, quando a concentração de cálcio foi superior no grupo tratado quando comparado ao controle (11,10 ± 1,751 vs. 9,610 ± 2,212 mg/dL, p = 0,03). A ocorrência de rete... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this study was to compare the serum concentrations of calcium, progesterone, insulin-like growth factor-1 (IGF-I), occurrence of milk microbiological growth and of retained placenta before drying off and after parturition in high production dairy cows treated or not with cabergoline. A total of 48 multiparous Holstein, Gyr x Holstein and Jersey x Holstein cows at the end of lactation period (approximately 60 days before partum) were used, with production above 14L/day and sorted into control and treated group receiving 5.6 mg of cabergoline via I.M. Blood samples for serum concentrations of progesterone, IGF-I and calcium were drawn on the day of drying off (before cabergoline injection), one day after drying off, seven days after drying off, between fifteen and seven days before partum and seven days postpartum; on the day of parturition and one day postpartum only calcium was measured. For microbiological analysis, milk samples were collected seven days before drying off, on the day of drying off and on the day of partum. In addition, occurrence of retained placenta were recorded. No significant difference was observed between the groups (p > 0.05) in the occurrence of mammary gland infection, calcium and hormones serum concentrations, except in the samples collected one week after calving, when the calcium concentration was higher in the treated group compared to the control group (11.10 ± 1.751 vs. 9.610 ± 2.212 mg/dL, p = 0.03). The occurrence of placent... (Complete abstract click electronic access below) / Mestre

Genetic relationship was analyzed between type traits and longevity measures in dual-purpose cattle. Data from 91 486 Czech Fleckvieh cows first calved between 2003 and 2009 were used. Longevity was defined as the actual number of lactations initiated per cow and also as functional longevity, which incorporated an adjustment to account for variation in voluntary culling based upon milk production. Lifetime performance was defined as cumulative milk production through the 6th parity. All cows were scored for conformation traits during their first lactation. Genetic correlations between these traits and longevity measures were estimated by bivariate analysis using the DMU variance component program package. Type trait heritabilities ranged from 0.30 to 0.59, while heritabilities for longevity and functional longevity were 0.06 and 0.05, respectively. Heritability of lifetime performance was 0.08. Genetic correlations between type traits and longevity measures ranged from low to intermediate values. Genetic correlations of the measured body size traits to the real and functional longevity ranged from ?0.06 to ?0.29, for udder traits from ?0.02 to 0.33, and for foot and leg traits from ?0.03 to 0.17. Genetic correlations between the measured body size traits and lifetime performance ranged from ?0.03 to ?0.30, for udder traits from 0.05 to 0.47, for foot and leg traits from ?0.07 to 0.15. Genetic correlations of composite trait scores for frame, muscularity, feet and legs, and udder with longevity traits ranged from ?0.20 to 0.41 and for lifetime performance ?0.14 to 0.51. The highest genetic correlations between a type trait and functional longevity were for composite udder score (0.25), feet and legs (0.26), and udder depth (0.33), suggesting that these traits could serve as indicators of functional longevity. We conclude that selection based upon easily and inexpensively measured type traits could improve functional longevity of cows as well as lifetime milk production.

Para suprir a crescente demanda pela produção de alimentos de origem animal baseada nos princípios do bem-estar, é importante que produtores de leite bovino se preocupem em identificar pontos fortes e fracos em seu sistema de produção, para que melhorias sejam realizadas, e sua manutenção neste mercado competitivo, favorecida. Sugere-se que há uma complementariedade entre aumento de produção causado por um melhor manejo (nutrição, instalações, controle sanitário etc.) e o aumento no nível de bem-estar animal - BEA. No entanto, percebe-se certa resistência dos pecuaristas para adoção de novas tecnologias e de instrumentos da administração e da gestão de empresas para proporcionar segurança nas tomadas de decisão de seu próprio negócio. Portanto, objetivou-se neste estudo, avaliar o retorno do investimento em melhorias para o bem-estar de vacas leiteiras em sistemas de produção em pasto e em confinamento. A partir da aplicação do protocolo de avaliação Welfare Quality&reg; em seis unidades produtivas de leite bovino no estado de São Paulo, foram identificados pontos críticos de BEA a serem melhorados. Com base em um orçamento para realização dessas melhorias e em referências na literatura, foi estruturado um fluxo de caixa incremental para avaliação dos projetos de investimento em cada sistema produção. De acordo com os resultados obtidos para os parâmetros econômicos payback, valor presente líquido (VPL) e taxa interna de retorno (TIR), ambos os projetos de investimento foram considerados economicamente atrativos. Por fim, visando ao aprofundamento deste estudo, que relaciona aspectos técnicos com a viabilidade econômica na pecuária leiteira, utilizou-se da simulação de modelos de \"bioeconômicos\" para realização da análise de investimento em estratégias isoladas de melhorias. Pode-se concluir que o conjunto dos resultados obtidos de acordo com os três objetivos permitiu associar ferramentas de gestão que integram fatores técnicos, biológicos, sociais e econômicos em sistemas de produção de leite em pasto e em confinamento de acordo com esses estudos de caso. / To meet the growing demand for production of animal-based foods while emphasizing principles of animal welfare, dairy farmers should be motivated to identify the strengths and weaknesses in their production system. By analyzing their production system, improvements can be implemented in order to improve gains in a competitive market. It is suggested that there is a correlation between increased production due to better management of nutrition, facilities, sanitary control etc. with the increased levels of animal welfare (AW). Traditional dairy farmers are reluctant when trying to adopt new technologies and business-management tools which would aide in important decision-making to protect their most valued asset; their own business. Therefore, the objective of this study was to evaluate the return on investment in improvements to the welfare of dairy cows on pasture and in confinement systems. Based on the application of the Welfare Quality&reg; evaluation protocol in six dairy farms in the state of São Paulo, critical points of AW for improvement were identified. Based on a budget to carry out these improvements and with references in available literature, an incremental cash flow for evaluation of investment projects in each of the two production systems was established. According to the results obtained through Payback economic parameters, net present value (NPV) and internal rate of return (IRR), both investment projects were considered economically attractive. Finally, in order to deepen this study which relates technical aspects with economic viability in dairy farming, bioeconomic simulation models were used to conduct the investment analysis in isolated strategies for improvement. Based on the three goas, it can be concluded that the use of tools that integrate technical, biological, social and economic aspects involved dairy production according with this study cases.

A eficiência reprodutiva é um parâmetro de extrema importância para a indústria moderna de leite, influenciando diretamente o desempenho econômico global das fazendas leiteiras. Aproximadamente metade da população de vacas leiteiras após o parto apresentam doenças uterinas, causando alterações do útero e ovário podendo levar a infertilidade, aumentando a possibilidade de descarte, gerando grande prejuízo econômico aos produtores leiteiros. Com o intuito de minimizar tais doenças e seus prejuízos, este trabalho teve como objeto avaliar a progressão da microbiota encontrada nas vaginas de vacas leiteiras Holandesas, durante o período de transição e as diferenças na composição bacteriana e carga bacteriana total (CBT) associada a doenças uterinas e fertilidade. Para tal, foram coletados uma swabs vaginais em duplicata de 573 vacas holandesas de uma fazenda leiteira comercial, nos dias -7, 0, 3 e 7 dias relativos ao parto. O presente estudo foi dividido em dois experimentos: No primeiro, foram selecionados swabs vaginais de 111 vacas. A microbiota foi caracterizada pelo sequenciamento do gene bacteriano 16S rRNA e a CBT foi determinada por PCR quantitativa em tempo real. Os fatores de risco relacionados com doença uterina foram Proteobacteria, Fusobacteria e Bacteroidetes. Vacas com retenção de placenta e vacas saudáveis apresentaram CBT similar no dia do parto, mas no D7, pós-parto, as vacas com a placenta retida demonstraram uma CBT significativamente maior, principalmente pela presença de grande quantidade de Fusobacteria e Bacteroidetes. Vacas diagnosticadas com metrite tiveram carga significativamente maior de Proteobactérias no D-7 e no D0 e maiores cargas estimadas de Fusobacteria no D3 e D7. Além disso, a carga de Bacteroidetes no D7 pós-parto foi maior para vacas diagnosticadas com endometrite aos 35 dias pós parto. Vacas que apresentaram febre no pós-parto, primíparas e que pariram gêmeos, também apresentaram maiores cargas de Fusobacteria e Bacteroidetes. Isso sugere que a composição da microbiota e 11 CBT estão associados à conhecidos fatores de risco para doenças uterina e falhas reprodutivas no periparto aumentando o risco de doenças uterinas e falhas reprodutivas incluindo número de partos, distocia e retenção de placenta. No segundo experimento, Swabs vaginais de 573 vacas leiteiras, foram coletadas de cada vaca nos seguintes pontos: 7, 0, 3, e 7 dias referentes ao parto, com o objetivo de monitorar o desenvolvimento da microbiota vaginal em um meio de cultura bacteriana cromogênico (Accumaster&reg;), para identificação do desenvolvimento de patógenos Streptococcus spp., Staphylococcus spp. e bactérias Gram-negativas (Escherichia coli). Houve diferença no crescimento bacteriano para Sthaphyloccus spp em todos os dias relativos ao parto, para E.coli no D-7 e D7 e (p&lt;0,05). A quantidade de animais com crescimento bacteriano para Sthaphyloccus spp e E.coli aumentou no parto e pós parto Foram fatores de risco para metrite a cetose (p&lt; 0,001), parto gemelar (p&lt;0,05), retenção de placenta e parto na maternidade (p&lt; 0,001). Varios fatores de risco ligados a doenças e doenças uterinas foram significativamente diferentes para as vacas que apresentaram crescimento bacteriano para E.coli no pós parto. / Reproductive efficiency is an extremely important parameter for the modern dairy industry, affecting the overall economic performance of dairy farms. Approximately half of the cows after childbirth present uterine diseases, causing changes in the uterus and ovary, leading to infertility, increasing the possibility of discarding, causing great economic harm to dairy farmers. The objective of this work was to evaluate the microbiota found in Holstein dairy cows during the transition period and the differences in bacterial composition and total bacterial load (CBT) associated with diseases and fertility. The present study was divided into two experiments: first, vaginal swabs from 111 Dutch cows from a commercial dairy farm were collected on days 7, 0, 3 and 7 days of delivery. The microbiota was characterized by the sequencing of the bacterial 16S rRNA gene and the CBT was determined by quantitative realtime PCR. The risk factors related to uterine disease were Proteobacteria, Fusobacteria and Bacteroidetes. Cows with retained placenta and healthy cows presented similar CBT on the day of calving, but in D7, postpartum cows with retained placenta demonstrated a significantly higher CBT, mainly due to the presence of large amounts of Fusobacteria and Bacteroidetes. Cows diagnosed with metritis had significantly higher burden of D-7 and D0 Proteobacteria and higher estimated Fusobacteria loads on D3 and D7. In addition, Bacteroidetes load in postpartum D7 was higher for cows diagnosed with endometritis at 35 days postpartum. Cows that presented postpartum fever, primiparous and who gave birth twins, also presented higher loads of Fusobacteria and Bacteroidetes. This suggests that the composition of the microbiota and CBT are associated with known risk factors for uterine diseases and peripartum reproductive failures, increasing the risk of uterine diseases and reproductive failures including number of deliveries, dystocia and retained placenta. In the second experiment, vaginal swabs from 573 dairy cows were collected from each cow at the following points: -7, 0, 3, and 7 days of delivery, with the objective of monitoring the development of the vaginal microbiota in a chromogenic culture medium (Accumaster&reg;) to identify the development of pathogens (Streptococcus spp., Staphylococcus spp. And Gram-negative bacteria). (E. coli) on the D-7 and D7, and on the other hand, the presence of E. coli in E. coli (p &lt;0.05). The number of animals with bacterial growth for Sthaphyloccus spp and E.coli increased at delivery and postpartum were risk factors for ketosis metritis (p &lt;0.001), twin birth (p &lt;0, 05), placenta retention and childbirth in the maternity ward (p &lt;0.001). Several risk factors related to uterine diseases and diseases were significantly different for cows that presented bacterial growth for E. coli in the postpartum period.

Duzentos e vinte e uma vacas (78 com bezerros entre 40 e 90 dias de idade) mestiças Nelore (Bos taurus indicus) X Charolês (Bos taurus taurus) foram utilizadas para avaliar a reutilização de implantes auriculares de silicone impregnados com progestágenos para controle farmacológico do ciclo estral e ovulação. Os tratamentos experimentais consistiram de três protocolos para sincroni zação do cio e inseminação artificial em tempo pré-determinado. No tratamento 1 (T1; n=73) as vacas receberam um implante auricular de Crestar® (3 mg de norgestomet); no tratamento 2 (T2; n= 75) as vacas receberam um implante auricular de Crestar® já utili zado anteriormente em outra sincronização; e no tratamento 3 (T3; n=73) as vacas receberam dois implantes auriculares de Crestar® também já utilizados, os quais foram colocados lado a lado na mesma orelha. Além dos implantes, as vacas receberam aplicação intramuscular (im) de uma associação de 2 mL de progesterona (25mg/mL) + benzoato de estradiol (1mg/mL) no momento da colocação dos implantes (D0). Os implantes foram removidos após 8 dias (D7) junto a uma aplicação (im) de Preloban® (150mg de D-cloprostenol). Após 24h da remoção do implante, foi aplicado uma dose (im) de Estrogin® (1mg de benzoato de estradiol). Todas as vacas foram inseminadas artificialmente 54-56h após a retirada dos implantes. Noventa por cento do sêmen utilizado no experimento foi proveniente de um só touro, os 10% restantes foram distribuídos equitativamente entre os tratamentos. A inseminação artificial foi realizada por um único inseminador. As vacas com bezerro ao pé apresentaram um escore de condição corporal entre 5 e 6, numa escala de 1 a 9, e as vacas sem bezerro entre 6 e 7. A variável estudada foi a taxa de prenhez das vacas. A análise estatística foi realizada com o auxílio do pacote estatístico "Statistical Analysis System 8.0", utilizando regressão logística. Não houve dife rença na taxa de prenhez das vacas, sendo 39,72%, 34,21% e 36,98% para os tratamentos T1, T2 e T3, respectivamente. A reutilização de implantes com progestágeno não altera a taxa de prenhez de vacas aptas à reprodução. / Two-hundred and twenty-one (78 suckling- 40 to 90 days) Nelore (Bos taurus indicus) X Charolais (Bos taurus taurus) cows were used to evaluate the reutilization of progestagen implants to control pharmacologically the estrus cycle and ovulation. Cows were randomly assigned to one of three protocols for estrous synchronization and artificial insemination in pre-fixed time. In treatment 1 (T1; n=73) cows were implanted with Crestar® (3 mg de norgestomet); in treatment 2 (T2; n= 75) cows were implanted with Crestar®, already used in a previous synchronization; and in treatment 3 (T3; n=73) cows received two Crestar® implants, also previously used, both placed side by side in the same ear. All cows were injected with an intra muscular (i.m.) dose of 2 mL of progesterone (25mg/mL) + estradiol benzoate (1mg/mL) at the time of implants insertion (D0). Implants were removed after 8 days (D7) and an i.m. dose of Preloban® (150mg de D-cloprostenol) was administered. Twenty-four hours after implants removal, cows were i.m. injected with a dose of Estrogin® (1mg of estradiol benzoate). All cows were artificially inseminated at 54-56 h after implants removal. Ninety percent of semen used in the experiment was from only one bull, the remaining 10% were equally distributed among treatments. Artificial insemination was performed by only one technician. Suckling cows had a body condition score of 5-6, in a scale of 1-9, and the non-suckling cows were 6-7. Pregnancy rate was the variable studied. Statistical analysis was accomplished by using "Statistical Analysis System 8.0", and logistic regression. There was no difference (P>0.05) on cow’s pregnancy rate among treatments. Pregnancy rates were 39.72, 34.21 and 36.98% for T1, T2 and T3, respectively. Progestagen implants reutilization did not affected pregnancy rate in beef cows ready for reproduction.

A hipótese do presente estudo sugere que a baixa fertilidade de vacas Holandesas (Bos taurus) repetidoras de serviço (RS) está relacionada à baixa qualidade oocitária que, por sua vez, é associada ao quadro de resistência periférica a insulina (RPI). Ainda, a indução de lactação (IL) em vacas Holandesas (Bos taurus) RS pode reverter o quadro de RPI e, consequentemente, melhorar a qualidade oocitária e a produção in vitro de embriões (PIVE). Para testar a hipótese proposta, este estudo objetivou avaliar o efeito da fase da lactação e da gestação [Exp. 1], o efeito da secagem de RS [Exp. 2] e o efeito da IL [Exp. 3] sobre a RPI, a qualidade oocitária e a PIVE em vacas da raça Holandesa (Bos taurus). Nos três estudos foram realizados testes de tolerância à glicose (TTG) para avaliar a RPI através do perfil hormonal sérico de insulina e glicose. Além disso, avaliou-se o perfil bioquímico sérico e folicular e a qualidade oocitária através da PIVE. Verificou-se que, em resposta à infusão de 0,3mg glicose/kg PV, as vacas RS no final da lactação secretaram 53% mais insulina e captaram 40% menos de glicose quando comparadas as vacas no terço inicial de lactação (Exp 1). Esses achados são indicativos do estabelecimento do quadro de RPI nas vacas RS em lactação. Durante o período seco, as vacas RS secretaram 96% mais insulina e captaram 56% menos glicose que as vacas no terço inicial da lactação e as vacas RS em lactação, respectivamente (Exp. 2). Ainda, as vacas com lactação induzida secretaram 11% menos insulina e captaram a mesma quantidade de glicose que vacas paridas em fases semelhantes de lactação (Exp 3), demonstrando que o protocolo de IL foi eficiente em alterar o perfil metabólico, revertendo o quadro de RPI presente nas vacas RS. Nos Exp. 1, 2 e 3 foram verificadas maiores concentrações plasmática de triglicérides (TG; P &lt; 0,05), colesterol total (COL; P < 0,05) e LDL (P < 0,05) no soro sanguíneo em vacas RS quando comparadas com vacas no terço inicial de lactação. Durante o período seco (Exp. 2 e 3), observou-se incremento desses metabólitos, destacando aumento na concentração de TG (P < 0,05), COL (P < 0,05) e LDL (P < 0,05) plasmático em vacas secas quando comparadas as vacas em lactação [início e final (RS) da lactação]. No liquido folicular foram observadas variações no perfil bioquímico para COL e TG. Nos Exp. 1, 2 e 3, verificou-se que vacas RS possuem maior concentração de TG (P < 0,05) e COL (P < 0,05) no fluido folicular do que vacas no terço inicial de lactação. Contrariando a hipótese inicialmente proposta, as vacas RS em lactação e as vacas secas apresentaram maior taxa de blastocisto (P < 0,05) e número de blastocistos por OPU (P < 0,05) que as vacas no terço inicial de lactação (Exp. 1, 2 e 3). Através do perfil de insulina circulante em resposta ao TTG foi possível demonstrar o estabelecimento do quadro de RPI em vacas RS (P < 0,05). Além disso, constatou-se agravamento da RPI em vacas secas (P < 0,05). Esse quadro foi associado ao aumento do escore de condição corporal (P < 0,05) e do peso vivo (kg; P < 0,05) nas vacas RS. Em conclusão, não foi verificada associação negativa entre RPI, qualidade oocitária e PIVE em vacas Holandesas (Bos taurus) RS. Apesar da indução de lactação em vacas Holandesas (Bos taurus) RS alterar o metabolismo e diminuir o quadro de RPI, não foi verificado efetivo positivo na qualidade oocitária e na PIVE. / The hypothesis of the present study suggests that low fertility of repeat breeders (RB) Holstein (Bos taurus) cows is related to low oocyte quality, which is associated with peripheral insulin resistance (PIR). Also, induction of lactation (IL) in RB Holstein (Bos taurus) cows can revert PIR and, consequently, improve oocyte quality and in vitro embryo production (IVEP). In order to test the proposed hypothesis, the objective of this study was to evaluate the effect of phase of lactation and gestation [Exp. 1], effect of drying RB [Exp. 2] and effect of IL [Exp. 3] on PIR, oocyte quality and IVEP of Holstein (Bos taurus) cows. In all three studies, glucose tolerance tests (GTT) were performed to evaluate PIR through the serum hormonal insulin and glucose profile. In addition, we evaluated the serum and follicular biochemical profile and oocyte quality through IVEP. It was verified that, in response to a 0.3mg glucose/kg of body weight (BW), RB cows at the end of lactation secreted 53% more insulin and captured 40% less glucose when compared to cows in the initial third of their lactation (Exp. 1). These findings are indicative of the establishment of PIR in RB lactating cows. During the dry period, RB cows secreted 96% more insulin and captured 56% less glucose than cows in the initial third of their lactation and RB lactating cows, respectively (Exp. 2). Also, cows with induced lactation secreted 11% less insulin and captured the same amount of glucose than calved cows in similar lactation phase (Exp. 3), demonstrating that the IL protocol was efficient to alter the metabolic profile, reverting PIR present in RB cows. In Exp. 1, 2 and 3 higher plasmatic concentrations of triglycerides (TG; P<0.05), total cholesterol (COL; P<0.05) and LDL (P<0.05) were verified in the blood serum in RB cows when compared to cows in the initial third of their lactation. During the dry period (Exp. 2 and 3), we observed the increment of these metabolites, and a notable elevation of the plasmatic TG (P < 0.05), COL (P < 0.05) and LDL (P < 0.05) in dry cows when compared to lactating cows [beginning and end (RB) of lactation]. In the follicular fluid, it was possible to observe variations in the biochemical profile for COL and TG. In Exp. 1, 2 and 3, it was verified that RB cows have higher concentration of TG (P < 0.05) and COL (P < 0.05) in the follicular fluid than cows in the initial third of their lactation. Contrary to the initially proposed hypothesis, RB lactating cows and dry cows presented higher blastocyst rate (P<0.05) than cows in the initial third of lactation (Exp. 1, 2 and 3). Through the circulating insulin profile in response to the GTT it was possible to demonstrate the establishment of PIR in RB cows (P<0.05). Also, it was observed worsening of the PIR in dry cows (P<0.05). This condition was associated with an increase in body condition score (P<0.05) and BW (kg; P<0.05) in RB cows. In conclusion, no negative association between PIR, oocyte quality and IVEP was observed in RB Holstein (Bos taurus) cows. Although induction of lactation in RB Holstein (Bos taurus) cows altered the metabolism and reduced PIR, no positive effect was observed in oocyte quality and IVEP.