O presente trabalho teve como objetivo avaliar o efeito de aditivos químicos, microbianos e a associação destes sobre a dinâmica fermentativa e a estabilidade aeróbia de silagens de cana-de-açúcar, além de avaliar o desempenho de vacas leiteiras de alto potencial produtivo recebendo rações com diferentes fontes de volumosos. No primeiro experimento silagens de cana-de-açúcar foram confeccionadas em silos laboratoriais de 20L, contendo válvula para escape de gases e coleta de efluente. O experimento seguiu o delineamento inteiramente ao acaso, em esquema fatorial sendo constituído por dois períodos de abertura (80 e 140 dias) com 8 tratamentos e 4 repetições. Os tratamentos avaliados foram: uréia 1%MV, 1,2- propanodiol 1%MS (1,2 p), L. L. buchneri 5x104 ufc/g (Lb), L. diolivorans em duas concentrações 1x105 ufc/g (Ld 105 e 1x10 6 ufc/g (Ld 106), L. diolivorans 1x106 ufc/g + L.buchneri 5x104 ufc/g (Ld+Lb) e 1,2-propanodiol 1%MS + L. diolivorans 1x 106 ufc/g (1,2 p+Ld 106). Após abertos os silos foram realizadas avaliações de estabilidade aeróbia em sala com ambiente controlado. Os tratamentos contendo L. diolivorans mais 1,2- propanodiol ou L. diolivorans mais L. buchneri apresentaram os menores valores de perda total de matéria seca 20,42% e 23,73%, respectivamente. Ambos tratamentos também resultaram nos menores teores de etanol, 2,1% e 3,93% da MS, e de perdas gasosas, 20,36% e 20,62%. Tanto para FDN quanto FDA, foram observados valores menores para os tratamentos contendo uréia, 1,2-p + Ld 106 Ld + Lb e Ld 105. Quanto à estabilidade aeróbia houve diferenças entre os períodos de abertura, sendo de 48,03h aos 140 dias e de 31,35h aos 80 dias. O microrganismo L. diolivorans se constituiu em uma alternativa capaz de trazer benefícios quanto às perdas fermentativas e composição bromatológica em silagens de cana-de-açúcar. O segundo experimento avaliou o desempenho de vacas recebendo rações contendo diferentes fontes de volumosos: cana-de-açúcar in natura, silagem de cana-de-açúcar inoculada com L. buchneri silagem de milho e proporções equivalentes de silagem de milho e cana-deaçúcar in natura (50:50). O experimento contou com 48 vacas Holandesas em estágio intermediário de lactação, distribuídas em múltiplos quadrados latinos 4x4 com períodos de 21 dias, sendo 14 dias de adaptação e 7 dias de coleta de amostras. Além da avaliação de desempenho, foram realizadas análises de composição bromatológica dos alimentos e do leite, e avaliações do comportamento ingestivo dos animais e da estabilidade aeróbia dos volumosos e das rações. Os dados de desempenho mostraram diferenças na ingestão de MS, com maiores valores observados para o tratamento silagem de cana-de-açúcar (23,5 kg/dia) e a mistura cana-de-açúcar mais silagem de milho (23,5 kg/dia). Todas as rações resultaram em produções elevadas de leite (22,65 kg/dia) as quais não diferiram entre si. A composição do leite variou somente para o teor de gordura, sendo maior para a silagem de milho (3,61%) e a mistura com cana (3,48%). A silagem de cana-de-açúcar mostrou-se como alternativa interessante frente à cana-de-açúcar in natura, e que ambas podem proporcionar elevadas produções desde que as rações sejam corretamente balanceadas. / The current study aimed to evaluate the effect of chemical and microbial additives and the combination over the fermentative dynamics and the aerobic stability in the sugarcane silage as well to study the performance of high producing dairy cows fed with different roughage sources. In the first trial, sugarcane silage was prepared in lab silos of 20L, with a gas relief valve and a device for collecting effluent. The experiment was randomly arranged, in a factorial design, with two openings 80 and 140 days, across 8 treatments and 4 replications. The treatments evaluated were: urea 1%, 1.2-propanediol 1%DM (1.2 p) L. buchneri 5x104 cfu/g (Lb), L. diolivorans in two concentrations 1x105 cfu/g (Ld 105) and 1x106 cfu/g (Ld 106), L. diolivorans 1x106 cfu/g plus L. buchneri 5x104 cfu/g (Ld+Lb) and 1.2- propanediol 1%DM plus L. diolivorans 1x 106 cfu/g (1,2 p+Ld 106). After opening the silos, the aerobic stability assay was performed in an environmental controlled room. The treatments containing Ld +1.2 p, or Ld 106 + Lb showed the lowest values of total DM loss, 20.42% and 23.73% respectively. Both treatments also showed the lowest levels of ethanol 2.1% and 3.93% of DM, and gases losses 20.36% and 20.62%. For both NDF and ADF, lower values were detected for the following treatments: urea, 1.2 p + Ld 106, Ld + Lb and Ld105. As for the aerobic stability, there were differences between the openings dates, 48.03h (140 days) and 31.35h (80 days). The microorganism L. diolivorans turn out to be promising alternative able to show positive results on the fermentative losses and nutritive value in sugarcane silage. The second experiment evaluated the performance of cows fed rations with different sources of roughage: fresh sugarcane, sugarcane silage, corn silage and mixture of corn silage and fresh sugarcane (50:50). Forty eight mid lactation Holstein cows were assigned to multiple latin square design 4x4, with 21-d period (14-d adaptation and 7-d the sample collection). As well the animal performance fed and milk compositions were evaluated and also ingestivo behavior of cows and the aerobic stability of forage and rations were analyzed. The performance data has shown differences in the dry matter intake (DMI), with the highest values observed for the sugarcane silage (23.5 kg/day) and the mixture (23.5 kg/day). All rations resulted in high milk production (22.65 kg/day) which did not differ among treatments. The milk composition varied only for the fat percentage, which was higher for the corn silage treatment (3.61%) and the mix (3.48%). Sugarcane silage was exhibited as an interesting forage alternative when compared to fresh sugarcane. Both options may support high milk yields by the adequacy of rations balancing.

Foram realizados três experimentos visando avaliar o uso de aditivos químicos durante a ensilagem da cana-de-açúcar. No experimento I, objetivou-se verificar as alterações nas características fermentativas e aeróbias das silagens de cana-de-açúcar ensiladas com 1% de cal virgem ou 1% de calcário (com base na matéria original). As menores (P<0,01) perdas gasosas foram observadas nos tratamentos contendo fontes de cal virgem ou calcário. As silagens tratadas com esses aditivos apresentaram maior (P<0,01) teor de carboidratos solúveis residuais e de ácido acético e butírico, além de reduzida fermentação alcoólica. Na estabilidade aeróbia, o tratamento com cal virgem apresentou maior estabilidade aeróbia, evidenciado pelo maior (P<0,05) tempo para elevação de temperatura e menores (P<0,05) perdas de matéria seca. No experimento II avaliou-se a digestibilidade dos nutrientes e os parâmetros de fermentação ruminal de borregos alimentados com rações contendo essas silagens, bem como a silagem não tratada e a cana-de-açúcar in natura. Foram utilizados 16 borregos não castrados da raça Santa Inês, alocados em gaiolas para ensaio de metabolismo. Todas as rações experimentais foram compostas de 50% de volumoso na matéria seca. Foram utilizadas quatro rações como tratamentos, diferindo quanto ao tipo do volumoso utilizado: canade- açúcar in natura, silagem de cana-de-açúcar sem aditivo, silagem de cana-deaçúcar aditivada com cal virgem (1%) e silagem de cana-de-açúcar aditivada com calcário (1%). Houve diferença (P<0,05) entre os tratamentos nos coeficientes de digestibilidade da matéria seca e da matéria orgânica, onde observou-se maior digestibilidade aparente da ração contendo cana-de-açúcar in natura. A concentração de butirato foi maior (P<0,05) nos animais que consumiram a ração contendo silagem tratada com 1% de cal virgem, apresentando valor de 11,89 mM. Os valores de pH ruminal não sofreram alteração (P>0,05) entre os tratamentos, apresentado valor médio de 6,3. No experimento III, objetivou-se avaliar o desempenho, retorno da atividade ovariana pós-parto e comportamento ingestivo de ovelhas em lactação, alimentadas com os mesmos tratamentos apresentados no experimento II. Foram utilizadas 40 ovelhas da raça Santa Inês individualmente alojadas em baias cobertas. Não houve diferença (P>0,05) entre os tratamentos na produção de leite. O teor de gordura do leite foi maior nas ovelhas que consumiram as rações contendo as silagens. Não verificou-se diferença (P>0,05) entre os tratamentos no número de dias necessários para ocorrer a primeira ovulação. A concentração de ácidos graxos não-esterificados não foi alterada (P>0,05) entre os tratamentos. Não foi verificada diferença (P>0,05) entre os tratamentos nas avaliações do comportamento ingestivo dos animais. O uso de fontes de cálcio como aditivos na ensilagem da cana-de-açúcar proporcionou melhor padrão fermentativo, com redução das perdas gasosas e da produção de etanol. O desempenho animal não foi afetado com a utilização dessas silagens. / Three experiments were conducted to evaluate the effects of fresh sugarcane or sugarcane silages added during ensiling with calcium oxide and limestone (1% as-fed basis). The experiment I assessed the fermentative characteristics and aerobic stability of silages and fresh sugarcane. The lowest gas losses were observed for treatments containing calcium oxide and limestone. These two treatments also showed low ethanol production and higher concentrations of residual soluble carbohydrates, acetic and butyric acids when compared with non-treated silage. In the aerobic stability trial, silage treated with calcium oxide presented the highest aerobic stability, observed by the heating delay and the lowest dry matter losses. Nutrient digestibility and ruminal parameters were also evaluated in the experiment II using sixteen Santa Inês ram lambs kept in metabolism crates. All experimental diet contained 50% of roughage (DM basis) and treatments were defined according to roughage type: fresh sugarcane, sugarcane silage with no additive, sugarcane silage with calcium oxide (1% as-fed basis), and sugarcane silage with limestone (1% as-fed basis). It was observed difference (P<0.05) among treatments for dry matter and organic matter digestibility with values of 74.62 and 76.43% for the diet containing fresh sugarcane, respectively. Ruminal butyrate concentration (11.89 mM) was the highest (P<0.05) for the animals receiving the diet with calcium oxide silage. There was no treatment effect on ruminal pH (P>0.05), with mean value of 6.3. In the experiment III, milk production, ovarian activity resumption, and ingestive behavior were evaluated using forty Santa Inês ewes individually penned. The ewes were fed with the same diet used in the experiment II. No effect on milk production (P>0.05) was observed. Milk fat concentration was higher (P<0.05) for ewes fed silages when compared to ewes fed sugarcane fresh sugarcane. There was no difference (P>0.05) for days necessary to P4 >= 1 ng/mL. Non-esterified fatty acids concentration and ingestive behavior were not affected (P>0.05) by treatments. Using calcium sources as sugarcane silage additive provided better fermentative pattern with reduction of gas losses and ethanol production. The animal performance was not affected by feeding sugar cane silage.

Foram realizados três experimentos visando avaliar diferentes estratégias de vedação. No experimento I, objetivou-se avaliar as características fermentativas e a estabilidade aeróbia das silagens de milho vedadas com diferentes tipos de filme plástico, aplicação na camada superior de aditivo químico ou microbiano e proteção do filme com terra, visando o controle da deterioração aeróbia. Houve diferença para o tipo de filme plástico utilizado, onde foi observado maiores valores de temperatura para as silagens vedadas com o filme de polietileno. As silagens aditivadas com benzoato de sódio ou Lactobacillus buchneri apresentaram menores perdas de matéria seca e menores valores de pH com relação a silagem não aditivada. Apenas em três amostras foram detectadas a presença de aflatoxina B1. No experimento II, objetivou-se avaliar estratégias de vedação, com base na proteção do filme plástico, visando o controle da deterioração aeróbia nas zonas periféricas do silo e o comportamento dessas silagens durante o período de aerobiose. No momento da abertura dos silos a contagem de leveduras foi maior para a silagem que não teve proteção sobre o filme plástico. A digestibilidade verdadeira in vitro da matéria seca apresentou diferença, sendo que as silagens que receberam proteção sobre a lona apresentaram os maiores valores em relação a silagem sem proteção sobre o filme plástico. No experimento III, objetivou-se avaliar diferentes tipos de filmes plásticos na vedação de silos horizontais e suas interferências relativas a qualidade das silagens, ao desempenho de vacas em lactação e qualidade do leite produzido. As maiores quantidades de silagem descartada foram para os tratamentos com a lona preta e lona dupla face. As maiores taxas de permeabilidade da lona ao oxigênio foram observadas para os filmes dupla face e preto de material virgem. A dieta que continha silagem proveniente do silo vedado com lona preta de material reciclado com proteção de bagaço apresentou o maior valor para a produção de leite, sendo a menor média verificada para o tratamento que continha filme plástico preto de material virgem. Ao longo das semanas de experimentação foi verificada a presença de aflatoxina B1 em todas as silagens. A partir do mês de agosto foi verificada positividade para aflatoxina M1 entre as amostras de leite. A dieta que continha silagem proveniente do silo vedado com lona preta de material reciclado e proteção de bagaço apresentou o maior valor de digestibilidade, tanto da matéria seca como da matéria orgânica das dietas. O polímero de poliamida, a proteção da lona com terra ou bagaço e o uso de aditivos como Lactobacillus buchneri ou benzoato de sódio reduzem a deterioração aeróbia de silagens de milho. A proteção da silagem contra o aquecimento, pelo uso da poliamida ou da proteção com bagaço, auxilia na obtenção de silagem de melhor qualidade e facilita o manejo pela redução da mão-de-obra no descarte de silagem deteriorada. O desempenho animal é afetado pela estratégia de vedação utilizada, podendo até mesmo afetar qualidade higiênica do leite produzido. / Three experiments were conducted to evaluate different strategies to cover the silo. The experiment I evaluate the fermentation profile and aerobic stability of com silage covered with different types of plastic sheets, applying additives in the top layer and, protecting the fi 1m with soil, to reduce the top losses in com silages. Higher temperature values were observed for the com silage covered with the polyethylene film. The use of additives showed lower DM losses and pH values in relation the control silage. The presence of aflatoxin 81 was detected in three samples only for the silage covered with polyethylene film, without additive and without soillayer over the top of the film. The experiment 11 was designed to study the effectiveness of covering methods to reduce the top losses in maize silages. The. yeast count was higher for control silage. The dry matter digestibility showed higher values for the protected silos in relation to unprotected treatment. The experiment 111 was designed to evaluate different plastic sheets to seal horizontal silos and their influence on the silage quality, Holstein dairy cows performance and milk quality. There was no difference between treatments for the fermentation profile. The silages temperature values in the silo top and top side increased in relation to samples in the panel center. The deteriorated discarded silage showed high values in silages covered with black virgin polyethylene and black-on-with polyethylene films. Those plastics films showed the highest rates of oxygen permeability. The diet containing silage from black recycled polyethylene with bagasse protection showed the highest value for milk yield, while the lowest milk yield was found to the black virgin polyethylene treatment. Over the experimentation period, the presence of aflatoxin 81 in silage was observed. The diet containing silage from black recycled film protect with bagasse treatment showed the highest digestibility of both dry matter and organic matter. The polyamide plastic film, the use of soil or sugarcane bagasse as a plastic film protection and, application of additives on the silo upper layer, reduce the com silage aerobic deterioration. Inhibiting the silage warming by using polyamide plastic film or sugarcane bagasse, helps in obtaining better quality silage management, reducing the costs and labor associated with the discarded silage. Animal performance is affected by the strategy used to seal the silage and may even affect hygienic quality of milk

No description available.

No description available.

Aufgrund der zu erwartenden Klimaveränderungen, insbesondere durch eine Erhöhung der Temperaturen und einer Zunahme der Extremsituationen (Hitze- und Kälteperioden), sollte vermehrt über Effekte von Hitzestress auf das Wohlbefinden und Leistungsvermögen von Tieren nachgedacht werden. Um den Einfluss von klimatischen Bedingungen (Temperatur und Temperatur-Humiditäts Index) auf die Gesundheit und das Leistungsvermögen von Milchkühen zu untersuchen, wurden drei Studien durchgeführt. Zuerst wurden die Auswirkungen des Temperatur-Humiditäts Index (THI) auf die Behandlungsfrequenz von Milchkühen ermittelt. Hierfür wurden die Daten aus den Bestandsbüchern von 2003 und 2005 von acht Milchviehbetrieben ausgewertet. Die Behandlungen wurden in vier Komplexe unterteilt: Stoffwechsel, Fruchtbarkeit, Euter und Klauen, wobei 37,4% der Behandlungen zum Stoffwechsel-, 32,9% zum Euter-, 21,6% zum Fruchtbarkeits- und 8,1% zum Klauenkomplex gehörten. Es zeigten sich ein tendenzieller Anstieg der Stoffwechselinzidenzen mit steigendem THI und ein nicht signifikanter Anstieg von Euterbehandlungen mit abfallendem THI. Die zu analysierenden Daten bezüglich des Einflusses auf das Leistungsvermögen wurden im Rahmen eines einjährigen Feldversuches vom April 2010 bis März 2011 aufgenommen. Hierfür wurden aus einem Pool von niedersächsischen Milchviehbetrieben 20 Betriebe mit unterschiedlichen Haltungssystemen (gedämmte und ungedämmte Laufställe mit und ohne Weidegang) ausgewählt. Auf diesen Betrieben wurden klimatische Werte (Stalltemperatur, relative Stallluftfeuchtigkeit und THI) als auch Herden- bzw. tierindividuelle Leistungsdaten (4% fettkorrigierte Milchmenge (FCM), Milchinhaltsstoffe und somatischer Zellscore (SCS)) anhand von Tankmilchproben bzw. Einzeltiermilchproben im Rahmen der Milchleistungsprüfung erfasst. Insgesamt wiesen die Untersuchungen unterschiedlich hohe Hitzestresseffekte auf die Milchleistung, Milchinhaltsstoffe und den SCS in den verschiedenen Haltungssystemen auf. Für die Milchmenge ergaben sich Regressionskoeffizienten von -0,12 kg FCM/THI und -0,11 kg FCM/THI bei gedämmten Laufställen ohne und mit Weidegang sowie -0,21 kg FCM/THI für Außenklimaställe ohne und mit Weidegang. Für den SCS ergaben sich bei den Stallhaltungssystemen Regressionskoeffizienten von +0.03 SCS/THI für gedämmte Systeme und +0,07 SCS/THI für Außenklimaställe. Basierend auf den Ergebnissen der Arbeit kann geschlussfolgert werden, dass Milchkühe in Niedersachsen während der Sommermonate Hitzestress ausgesetzt waren, wohingegen sich die Auswirkungen je nach Haltungssystem differenziert darstellten. Des Weiteren konnte gezeigt werden, dass in dem System mit gedämmtem Dach niedrigere Auswirkungen mit steigendem THI zu finden waren.

Il benessere degli animali è uno dei temi più discussi temi delle scienze animali. Molti ricercatori hanno provato a darne una definizione e a sviluppare strumenti utili alla sua valutazione negli allevamenti di vacche da latte. Nel presente lavoro viene discussa la possibilità di valutare il benessere degli animali, attraverso sistemi di innovazione da diversi punti di vista: scientifico, economico e zootecnico. Quattro differenti ricerche sono state sviluppate per confrontare i risultati sulla valutazione del benessere degli animali negli allevamenti da latte ottenuti con: indici fisiologici, modello SDIB e un sistema di monitoraggio della ruminazione. / Animal welfare is one of the most discussed topic in the animal science. Many researchers have been proving to define animal welfare and to develop tools useful to assess its levels in dairy farms. In the present issue it is discussed with different point of view (scientific, economical and zootechnic) the opportunity to assess the animal welfare through innovations system. Our different research was develop to compare the results about animal welfare in dairy herds obtained by physiological indices as well as blood variables, a model for animal welfare assessment as well as IDSW model, a rumination monitoring system.

Šiuo tyrimu buvo siekiama nustatyti koreliaciją tarp karvių didžiojo prieskrandžio turinio fermentacinių procesų aktyvumo rodiklių ir pieno produkcijos rodiklių. Taip pat - nustatyti karvių didžiojo prieskrandžio fermentacinių procesų rodiklių tarpusavio koreliaciją. Bandomosios LJ karvės (n=5) buvo tirtos ganykliniu ir tvartiniu laikotarpiais. Buvo ištirti šie didžiojo prieskrandžio fermentacijos rodikliai: pH, redukcinis bakterijų aktyvumas, gliukozės rūgimo reakcija, pirmuonių skaičius, lakiųjų riebalų rūgščių kiekis. Taip pat - pieno rodikliai: pieno kiekis, pieno riebalai, pieno baltymai, pieno laktozė, šlapalas. Koreliacijos koeficientai (rS) buvo apskaičiuoti pagal Spearman‘ą. Gauti rezultatai yra statistiškai nepatikimi, išskyrus, koreliaciją tarp didžiojo prieskrandžio pirmuonių ir pieno riebalų (rS = 0.9, p = 0,037) bei pirmuonių skaičiaus ir pieno baltymų (rS = 0.9, p = 0,037) tvartiniu laikotarpiu. Pastovią koreliaciją tvartiniu ir ganykliniu laikotarpiais išlaikė pirmuonių skaičius ir pieno kiekis (rS = –0,8 (p>0,05). Koreliacija, tarp redukcinio bakterijų aktyvumo ir pirmuonių skaičiaus, bei koreliacija, tarp lakiųjų riebalų rūgščių (LRR) ir pirmuonių skaičiaus, tiek tvartiniu ( atitinkamai rS = 0,872, p>0,05; rS = 0,1, p>0,05), tiek ganykliniu laikotarpiais (atitinkamai rS = 0,289, p>0,05; rS = 0,707; p>0,05), išliko teigiama. Neigiama koreliacija tvartiniu (rS = –0,205, p>0,05) ir ganykliniu (rS = –0,408, p>0,05) laikotarpiais išliko tarp redukcinio bakterijų... [toliau žr. visą tekstą] / This study was designed to determine a correlation between rumen fermentation process activity rates and milk production, also to establish a correlation between the rumen fermentation indicators. The study group was consisted of five LJ cows, which were tested during indoor and outdoor periods. In this study we have measured ruminal pH, bacterial activity reduction, glucose fermentation reaction, number of protozoa and volatile fatty acids also milk indicators such as milk fat, milk proteins, milk lactose, and milk urea. Correlation coefficients (rS) were calculated according to Spearman. The results are not statistically significant, except correlation results during the stable period between rumen protozoa count and milk fat (rS = 0.9, p = 0.037) also between number of protozoa and milk proteins (rS = 0.9, p = 0.037). A correlation constant between number of protozoa and quantity of milk (rs = -0.8, p < 0.05) was stable during both periods. During indoor and outdoor periods correlation between reduction activity of bacteria and number of protozoa, volatile fatty acids (VFA) and number of protozoa, (respectively, rS = 0.87, p<0.05, rS = 0 1, p> 0.05 and rS = 0.289, p> 0.05, rS = 0.707, p> 0.05) remained positive. During both periods negative correlation remained between reduction activity of bacteria and VFA (respectively rS = -0.205, p> 0.05, rS = -0.408, p <0.05).

Organic dairying is growing in popularity in New Zealand and the demand for knowledge is ever increasing. Many more farmers are considering organics as an alternative to their current conventional system. However, limited information is available on organic dairying in a New Zealand pastoral situation particularly in relation to its effect on fertility. The New Zealand dairy industry requires the dairy cow to become pregnant every year at the same time to maximise milk production and utilise the high pasture production in spring. A cow requires 40 to 60 days for uterine involution to occur and for resumption of oestrous cycles. It is critical that the cow becomes pregnant within the six to eight week mating period, however, this can be difficult for late calvers or those cows that had or still have a uterine infection, to undergo uterine involution and be successfully mated. These cows will often not become pregnant and as a consequence be culled for infertility. During the first few weeks postpartum, the bacterial composition of the uterus fluctuates as a result of spontaneous contamination, elimination and recontamination. Most cows are able to eliminate these bacteria, however, 10 to 17% of cows are unable to do this. In these cows, the bacteria persist, cause infection and inflammation, and delay uterine involution. The main objective of this present study was to investigate the effect of different management systems (Organic and Conventional) on productivity and reproduction, particularly the process of uterine involution and its relationship with reproductive outcomes. Uterine involution will be studied through the following measurements: cervical diameter as assessed by measurement per rectum, plasma concentrations of glucocorticoids and bacteriology of the uterus. Lactation characteristics: milk yield, cumulative milk yield, milksolids production and somatic cell count will also be investigated. From the results, it can be concluded that Organic cows have reduced milk yield (P=0.05) and milksolids production (P<0.01) through there were no major differences at peak lactation or in the rate of decline after. However, overall somatic cell count was not affected by management system though the Conventional cows had high somatic cell counts in early lactation (P=0.925). Cervical diameter was affected by the management system with the difference between Organic and Conventional cows almost significant (P=0.06). Cortisol concentrations were significantly higher in Organic cows (0.68 ± 0.08 ng/ml) when compared to Conventional cows (0.95 ± 0.06 ng/ml) (P=0.01). Cortisol concentrations decreased over time postpartum (P<0.01). Additionally Organic cows had a shorter interval from calving to AI (P=0.017). However, none of the other reproductive outcomes were affected by management system. Simple correlations established that reproductive outcomes and bacterial counts, reproductive outcomes and cortisol at Day seven, and cortisol and milk production characteristics, were not independent of each other. Aerobic bacterial counts on Day 28 and the interval from calving to AI were found to be significantly correlated (r= 0.615). Stepwise partial regression analysis, plus analysis of variance calculated on the relationships between uterine involution parameters and reproductive outcomes found multiple weak correlations. It found that cervical diameter, and aerobic and anaerobic bacterial counts on Day 28 were significantly correlated with the interval from calving to first AI (P=0.018). The differences in lactation characteristics are related to the lower pasture production on the organic farmlet reducing the maximal potential milk production and the possibly earlier calving dates of the Conventional cows. The differences in bacterial counts and almost significant difference in cervical diameter may be related to the lower cortisol levels and thus suggest that the Organic cows may be less stressed. As stress suppresses the immune system, it may be possible that the higher bacterial counts are indicitative of a less efficient or slightly weakened immune system which takes longer to eliminate bacteria in the uterus; however this is open to conjecture. The shorter interval from calving to AI suggests that Organic cows may be exhibiting oestrus behaviour earlier postpartum or the Conventional cows are having “silent heats” but this difference is possibly related to human factors. The correlation between parameters of uterine involution and interval from calving to AI, and the lower values for uterine involution parameters in Organic cows suggest the possibility of faster uterine involution and this may result in better fertility in the Organic cows. More research needs to be carried out to further investigate the effect of organic dairying on uterine involution and reproduction outcomes but organic dairying at the very least does not negatively impact on uterine involution and fertility.

Content removed due to copyright restrictions: Burggraaf, V.T., Kemp, P.D., Thom, E.R., Waghorn,G.C., Woodfield, D.R. & Woodward, S.L. (2004) Performance of dairy cows grazing white clover selected for increased floral condensed tannin. Preliminary report from experiments presented in Chapter 4 published in the 2004 Proceedings of the New Zealand Grassland Association. / Legumes containing 20 to 40 g of condensed tannin (CT) per kg of dry matter (DM) can improve dairy cow milk production by reducing ruminal protein degradation to ammonia and preventing bloat. White clover (Triflium repens L.) produces CT in its flower heads. High tannin (HT) white clover, bred for increased flowering and increased floral CT concentration, was evaluated under dairy grazing in Hamilton, New Zealand. Its performance in monoculture was compared to that of Grasslands Huia white clover over two years, and five short-term grazing experiments determined its effects on Friesian dairy cows. Huia and HT had similar floral CT concentrations, ranging from 15 to 77 g/kg DM over two flowering seasons. HT clover had higher flower densities than Huia until the second summer after sowing, resulting in higher clover (leaf plus flower) CT concentrations. Clover CT peaked at 12.1 g/kg DM for HT and 5.7 g/kg DM for Huia. HT swards had lower stolon growing point densities than Huia swards and annual DM yields averaged 10.0 and 11.0 t DM/ha for the respective clovers. The ingress of non-sown white clover genotypes reduced treatment differences in the last 10 months of the experiment. Mild bloat occurred in cows grazing both clovers. Cows grazing HT white clover had rumen ammonia concentrations 5 to 26% lower than that of cows grazing Huia, indicating less proteolysis in the rumen of HT cows, but there were no consistent effects on rumen soluble protein or volatile fatty acids (VFA). Differences between treatments in dietary CT concentrations were too small to affect milk production or composition. Minced mixtures of 0, 25, 50, 75 or 100% of DM as white clover flower with the remainder as white clover leaf, were incubated in vitro and rumen metabolite concentrations determined at 0, 2 ,4, 8, 12 and 24 hours. Polyethylene glycol was added to one of the 50% flower treatments to inactivate CT. Clover flowers had less soluble protein than leaves at 0 hours, and increasing the percentage of flowers from 0 to 100% reduced the net conversion of plant-N to ammonia-N from 29 to 12%. The contribution of CT to these effects was small. Increasing percentages of clover flowers did not significantly affect total VFA production but increased acetate to propionate (A:P) ratios. White clover CT decreased A:P ratios. In another in vitro experiment perennial ryegrass leaf (Lolium perenne L.) was incubated either alone or with white clover flowers or birdsfoot trefoil (Lotus corniculatus L.). Clover flowers were more effective at reducing proteolysis than birdsfoot trefoil, due largely to less release of soluble protein, but birdsfoot trefoil treatments had the lowest A:P ratios. In conclusion, HT clover had higher forage CT concentrations than Huia because of increased flowering. Increased flowering reduced the agronomic performance of HT and lowered rumen ammonia concentrations, but did not increase milk production or prevent bloat. White clover flowers reduced rumen proteolysis in vitro, but this was mainly a result of their low protein concentration. White clover CT and birdsfoot trefoil forage benefited the molar percentages of VFA, but increasing the proportion of clover flowers did not. Further increases in white clover CT concentrations may benefit ruminant performance, but this should not be implemented through increased flowering.