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We evaluated the reproductive losses in three periods: period I ­ starting from the time the cows were exposed to the bulls to pregnancy diagnoses (PD, number of cows diagnosed as non-pregnant/total exposed cows × 100); period II ­ from the time of PD to calving (number of calving cows/number of cows diagnosed as pregnant × 100); and period III ­ from calving to weaning (number of weaned calves/number of calving cows × 100) in purebred Hereford (HH) and Angus (AA) cows and their crosses in beef cows under extensive production systems. Likewise, the effect of parity (nulliparous, primiparous, and multiparous) and the interaction between both factors were studied. A thirteen-year data set (2505 record) of an experimental breeding herd, maintained in an extensive production system based on natural grassland, was used. The dataset was under a complete diallel design between HH and AA breeds. Both the genetic group and parity of the cow affected the reproductive losses, but only in period I. No interaction was found. Purebred cows had higher reproductive losses than the crossbred cows, without differences between the purebred (HH and AA) or between the crossbred (AH and HA). The greatest losses were observed rather in primiparous than in nulliparous and multiparous cows without difference between the latter two. The use of crossbred cows in extensive production systems is an alternative to reduce reproductive losses and to increase calf harvest.(AU)

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Supplementation strategies have been studied to increase animal performance and the quality of meat. Thus, this study was carried out to evaluate the influence of different supplementation strategies on the performance, feed intake, digestibility and ingestive behaviour of crossbred steers on Brachiaria brizantha pasture, during the dry season. The experiment was performed in Bahia, Brazil, from August 2015 to January 2016, with a dry season of 203 days. Thirty-three crossbred steers with an average weight of 269.5 ± 41.8 kg were distributed in a completely randomised design with three treatments and 11 replicates per treatment. The results were analysed using an ANOVA and a Tukey test, with a 5% probability of error. The treatments were mineral salt with urea and the supplementation of protein based on the animals' body weight (BW), as follows: 0.1 and 0.2% BW. There was no effect of supplementation strategy on the initial and final body weights. Supplementation strategies did not influence (p > 0.05) the variables related to the intake of total dry matter. There was an effect (p < 0.05) on the dry matter and crude protein digestibility coefficients. For ingestive behaviour, feed intake, grazing time and idle time tended to be altered by the supply strategies (p < 0.05), but rumination was not affected (p > 0.05) by the evaluated strategies. In conclusion, the supplementation strategies used during the dry season resulted in a similar performance; therefore, the adopted strategy can be chosen according to the economic and regional conditions of the production system. Thus, the strategy adopted could be chosen according to the economic and regional conditions of the production.(AU)

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This study aimed to evaluate food additives for the replacement of monensinand virginiamycin in high-grain diets for cattle. A Latin square experimental design was adopted, represented by four treatments (functional oil, yeast, tannin and control monensin and virginiamycin) in four experimental periods, with four animals cannulated in the rumen. l The natural ruminal modulators fully replaced the ionophores monensin and virginiamycin in the concentrate. Being evaluated: ruminal pH, apparent digestibility and in situdegradability of dry matter. The results showed that the pH variation curve as a function of rumen fluid collection time was not significant (P<0.05) among the additives studied. The additives used to replace monensin and virginiamycin in crossbred cattle fed a diet of 70% concentrate and 30% roughage with fractionation five times a day, are efficient in maintaining rumen pH above 6.0. The additives did not affect digestibility of OM, CP, NDF, FDA and EE.The in situ degradability of the soluble and potentially degradable fractions was higher in the yeast and essential oil treatments, respectively.The additives evaluated are efficient in replacing monensin and virginiamycin.

Objetivou-se com o presente estudo avaliar aditivos alimentares em substituição a monensina mais virginiamicina em dietas de alto grão para bovinos. Foi adotado o delineamento experimental em quadrado latino, representado por quatro tratamentos (Óleo funcional, Levedura, Tanino e o controle monensina e virginiamicina) em quatro períodos experimentais, com quatro animais cânulados no rúmen. Os moduladores ruminais naturais substituíram integralmente os ionóforos monensina mais virginiamicina no concentrado. Sendo avaliados: pH ruminal, digestibilidade aparente e a degradabilidade in situda matéria seca. Os resultados mostraram que a curva de variação do pH em função do tempo de coleta de líquido ruminal não foi significativa (P<0,05) entre os aditivos estudados. Os aditivos utilizados em substituição a monensina mais virginiamicina para bovinos mestiços com dieta 70% concentrado e 30% volumoso com fracionamento cinco vezes ao dia, são eficientes na manutenção do pH ruminal acima de 6,0. Não diferindo os aditivos na digestibilidade aparente de MO, PB, FDN, FDA e EE. A degradabilidade in situ apresentou maiores valores para a fração solúvel e potencialmente degradável nos tratamentos com levedura e óleos essenciais, respectivamente. Sendo os aditivos avaliados eficientes na substituição a monensina e virginiamicina.

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The use of crop residue silages is a viable alternative for producers to reduce feed costs. The present study was developed with the objective of investigating the inclusion of pineapple silage in replacement of sorghum silage in the diet of lactating cows regarding feed intake, production, and quality of milk. Eight crossbred (Holstein × Gir) cows with an average weight of 555±30 kg and an average milk yield of 12.50±3.25 kg/day, between 60 and 90 days in milk, were distributed into two simultaneous 4 × 4 Latin squares, at one animal per experimental unit. Silage of pineapple crop residue (PS) using plants after the harvest of the fruits was included in the roughage portion of the diet at increasing levels, with simultaneous and proportional removal of sorghum silage (SS) from the diets. The studied treatments thus consisted of the roughage portion containing: 1- 0% PS and 100% SS (100SS); 2- 34% PS and 66% SS (34PS66SS); 3- 67% PS and 33% SS (67PS33SS); 4- 100% PS and 0% SS (100PS). The diets were supplied twice daily, allowing 5% leftovers in relation to the quantity offered. The amounts of feed supplied, and orts of each animal were weighed for a subsequent determination of intake. The experiment was divided into four 21-day sub-periods, the first 14 days of which were used as an adaptation to the diet, while the others served for data collection. The milk was weighed from the 15th to the 19th day of each experimental period, and milk samples were collected on the last day of each period. Milk samples were sent to the laboratory, where they were analyzed. Dry matter, mineral matter, and lignin concentrations in the diet did not vary (P>0.05) as a function of PS inclusion in the roughage portion, while protein content, fiber content, and fat content levels were influenced. No effect of PS inclusion was observed (P>0.05) on the intakes of dry matter, neutral detergent fiber, mineral material, or lignin. However, PS inclusion prompted (P<0.05) a linear increase in the intakes of protein and total fat. The inclusion of pineapple plant silage in the roughage part of the diet had a positive effect (P<0.05) on milk yield, 4% fat-corrected milk yield, and on the milk fat and total solids contents. Milk production, as well as fat and total solids content, increased moderately with inclusion of pineapple plant silages in the roughage portion of the diet. Therefore, pineapple silage can replace sorghum silage in the roughage part of diets for lactating crossbred cows.(AU)

A utilização de silagens de resíduos culturais é uma alternativa viável para os produtores reduzirem custos com alimentação. O presente estudo foi desenvolvido com o objetivo de investigar a inclusão da silagem de abacaxi em substituição à silagem de sorgo na dieta de vacas lactantes quanto ao consumo de ração, produção e qualidade do leite. Oito vacas mestiças (Holstein × Gir), com peso médio de 555±30 kg e produção média de leite de 12,50±3,25 kg/dia, entre 60 e 90 dias de lactação, foram distribuídas em dois quadrados latinos 4 × 4 simultâneos, em um animal por unidade experimental. A silagem de resíduo da cultura do abacaxi (PS) utilizando plantas após a colheita dos frutos foi incluída na porção de volumoso da dieta em níveis crescentes, com retirada simultânea e proporcional da silagem de sorgo (SS) das dietas. Os tratamentos estudados consistiram, portanto, na porção de volumoso contendo: 1- 0% PS e 100% SS (100SS); 2- 34% PS e 66% SS (34PS66SS); 3- 67% PS e 33% SS (67PS33SS); 4- 100% PS e 0% SS (100PS). As dietas foram fornecidas duas vezes ao dia, permitindo sobras de 5% em relação à quantidade oferecida. As quantidades de ração fornecida e sobras de cada animal foram pesadas para posterior determinação do consumo. O experimento foi dividido em quatro subperíodos de 21 dias, sendo os primeiros 14 dias utilizados como adaptação à dieta, enquanto os demais serviram para coleta de dados. O leite foi pesado do 15º ao 19º dia de cada período experimental, e as amostras de leite foram coletadas no último dia de coleta de cada período. As amostras de leite foram enviadas ao laboratório, onde foram analisadas. As concentrações de matéria seca, matéria mineral e lignina na dieta não variaram (P>0,05) em função da inclusão de PS na porção de volumoso, enquanto os teores de proteína, teor de fibra e teor de gordura foram influenciados. Não foi observado efeito da inclusão de PS (P>0,05) nos consumos de matéria seca, fibra em detergente neutro, material mineral ou lignina. No entanto, a inclusão de PS provocou (P<0,05) um aumento linear na ingestão de proteínas e gorduras totais. A inclusão de silagem de abacaxi na parte volumosa da dieta teve efeito positivo (P<0,05) na produção de leite, na produção de leite corrigida em 4% para gordura e nos teores de gordura e sólidos totais do leite. A produção de leite, bem como o teor de gordura e sólidos totais aumentaram moderadamente com a inclusão de silagens de abacaxi na porção de volumoso da dieta. Portanto, a silagem de abacaxi pode substituir a silagem de sorgo na parte de volumoso das dietas de vacas mestiças em lactação.(AU)

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The impact of GnRH treatment on the day of TAI in beef cows has received limited investigation, especially concerning its association with estrus expression. Consequently, two experiments were conducted to assess the potential of GnRH treatment on the day of TAI to enhance fertility according to the expression or not of estrus in beef cows. Experiment 1 aimed to determine ovulation rate and luteal function, while Experiment 2 aimed to determine the effect of the two GnRH treatment approaches on pregnancy rate. In Experiment 1, multiparous Brangus suckling cows (n = 17) were submitted to an 8-day TAI protocol. Estrus occurrence was evaluated based on chalk removal on D10 (TAI) and cows were assigned to receive GnRH (25µg lecirelin; im) according to the group: GnRH (n = 7), regardless of estrus expression; or selectGnRH (n = 10), only cows not detected in estrus. Ovulation rate occurring until 77h after IVD removal did not differ (p = 0.17) between GnRH (85.7%; 6/7) and selectGnRH (100%; 10/10). Also, corpus luteum size and serum progesterone concentration were not affected (p>0.05) by treatments. In Experiment 2, crossbred taurine suckled cows (n = 384) were submitted to the same protocol as described in Experiment 1 and were randomly allocated to GnRH or selectGnRH groups. There was no difference in P/AI between groups (selectGnRH = 55.6%; GnRH = 54.3%; p = 0.7) 30 days after TAI. As expected, there was a pronounced effect (p<0.0001) of estrus expression on P/AI (Estrus = 61.5%; No estrus = 33.0%), regardless of group. In summary, ovulation timing and rate and luteal function did not differ between groups. Also, GnRH administration only in cows that do not show estrus is recommended, considering hormone savings and similar conception rate.(AU)

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As malformações congênitas surgem no desenvolvimento embrionário e podem ser funcionais ou estruturais, afetando diversos órgãos e tecidos, podendo ter como causas fatores ambientais, genéticos ou iatrogênicos. Dentre essas malformações, pode-se citar a microtia, que se caracteriza pela malformação da pina, resultando em uma hipoplasia de pavilhão auricular externo, apresentando anormalidade no tamanho, contorno ou ausência total da aurícula e lóbulo, condição que na maioria dos casos é unilateral e resulta em perda auditiva, especialmente quando associada à atresia do canal auditivo. O objetivo deste trabalho foi relatar os principais achados clínicos em um caso de microtia e atresia do conduto auricular externo, congênito em um bovino no estado do Amazonas-BR. Foi atendido pelo Serviço Médico Veterinário do Instituto Federal de Educação, Ciência e Tecnologia do Amazonas - IFAM, campus Lábrea, uma bezerra mestiça (Jersey + Girolando), para manejo neonatal. Durante o exame físico do animal foi observada alteração anatômica na pina esquerda, caracterizada por microtia de pina e ausência do conduto auditivo externo. Não foram observadas alterações anatômicas na orelha direita. Este caso destaca a necessidade de exame físico e avaliação clínica minuciosa em neonatos, pois anomalias auditivas podem não apresentar sinais neurológicos evidentes.(AU)

Congenital malformations arise during embryonic development and can be functional or structural, affecting various organs and tissues, and may be caused by environmental, genetic, or iatrogenic factors. Among these malformations, microtia can be mentioned, which is characterized by malformation of the pinna, resulting in hypoplasia of the external ear, which presents as an abnormality in the size, contour, or total absence of the auricle and lobe, a condition that in most cases is unilateral and often results in hearing loss, especially when associated with atresia of the auditory canal. The objective of this study was to report the main clinical findings in a case of microtia and atresia of the external ear canal, congenital in a bovine in the state of Amazonas. A crossbred (Jersey + Girolando) heifer was treated by the Veterinary Medical Service of the Federal Institute of Education, Science, and Technology of Amazonas - IFAM, Lábrea campus, for neonatal management. During the physical examination of the animal, an anatomical alteration was observed in the left pinna, characterized by pinna microtia and the absence of the external auditory canal. No anatomical alterations were observed in the right ear. This case highlights the need for thorough physical examination and clinical evaluation in neonates, as hearing anomalies may not present with obvious neurological signs.(AU)

Las malformaciones congénitas surgen en el desarrollo embrionario y pueden ser funcionales o estructurales, afectando diversos órganos y tejidos, y pueden ser causadas por factores ambientales, genéticos o iatrogénicos. Entre estas malformaciones podemos mencionar la microtia, que se caracteriza por la malformación del pabellón auricular, dando lugar a una hipoplasia del pabellón auricular externo, presentando una anomalía en el tamaño, contorno o ausencia total del pabellón auricular y lóbulo de la oreja, condición que en la mayoría En algunos casos es unilateral y produce pérdida de audición, especialmente cuando se asocia con atresia del canal auditivo. El objetivo de este trabajo fue relatar los principales hallazgos clínicos en un caso de microtia y atresia del conducto auditivo externo, congénita en un bovino en el estado de Amazonas-BR. Un ternero mestizo (Jersey + Girolando) fue atendido por el Servicio Médico Veterinario del Instituto Federal de Educación, Ciencia y Tecnología de Amazonas - IFAM, campus Lábrea, para manejo neonatal. Durante el examen físico del animal se observaron cambios anatómicos en el pabellón auricular izquierdo, caracterizados por microtia del pabellón auricular y ausencia del conducto auditivo externo. No se observaron cambios anatómicos en el oído derecho. Este caso resalta la necesidad de un examen físico y una evaluación clínica exhaustiva en los recién nacidos, ya que las anomalías auditivas pueden no presentar signos neurológicos obvios.(AU)

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The present study presents a comparative evaluation of the transit kinetics of straw briquette in response to the dietary addition of non-protein nitrogen sources in the form of a mineral supplement. Four rumen-cannulated, castrated Holstein-Gir crossbred cattle, weighing an average of 380±22.64 kg, were distributed into a 4 × 4 Latin square design (four supplements with non-protein nitrogen sources × four experimental periods). The following non-protein nitrogen sources were studied: conventional urea, slow-release urea, extruded urea, and monoammonium phosphate. During the experiment, the animals were housed in individual stalls with concrete floors where they received a basal diet consisting of straw briquette, potato starch, and the mineral supplement, the latter whose variation was only in the non-protein nitrogen source, which characterized the treatments. The different non-protein nitrogen sources did not affect the parameters of transit or degradation kinetics of straw fiber briquette. These results can be associated with the low nitrogen content limited by the types of supplements and the particle size of straw briquette, which is smaller due to processing.(AU)

Resumo

The objective of this study was to assess the effects of high-concentrate diets with and without the inclusion of soybean hull (SH; 0 or 500.8 g/kg) plus corn (whole or ground) on the performance, morphometric traits, and nutritional and metabolic parameters of crossbred dairy calves. We also aimed to assess the costs associated with the experimental diets employed. Thirty-six male calves with an average weight of 89±18.6 kg and age of 3.5 months were allocated to four treatments, with nine replicates of one calf/pen, in a completely randomized experimental design for 198 days. The inclusion of the SH and the physical form of corn did not influence animal performance or morphometric measurements; however, SH inclusion increased the digestibility of neutral detergent fiber and the intakes of dry matter and neutral detergent fiber, but did not affect total digestible nutrient intake. The physical form of corn did not influence nutrient intake or digestibility, which resulted in similar performance across the animals. Blood glucose levels as well as alkaline phosphatase and creatinine remained elevated regardless of the diet. The use of SH reduced the total plasma cholesterol content, and there was an interaction between the physical form of corn and SH inclusion in relation to creatinine levels, which were higher when using diets with whole corn and SH. Although the inclusion of up to 500.8 g/kg of SH in the diet reduces feed efficiency, its use decreases the cost per kilogram of weight gain. Dairy calves can exhibit satisfactory production performance when fed alternative ingredients such as whole corn or SH, which have a lower cost than ground corn, traditionally used in diet formulations.(AU)

Resumo

This trial was designed to evaluate the effect of processing method of rehydrated corn grain silage (RCGS) on feed intake, performance, carcass traits, feeding behavior, rumen morphology, and blood metabolites of cattle in the finishing phase. Thirty-eight F1 Angus × Nellore bulls (365±22 kg) raised under grazing conditions were housed in individual pens (2 × 4 m) for the feeding trial. At the end of the adaptation period, animals were weighed after a 16-h fast, blocked by shrunk body weight, and randomly assigned to one of two dietary treatments: GRC, consisting of RCGS that was ground before ensiling using a hammer mill with a uniform 8-mm screen (1.52 mm geometric mean particle size); and RRC, consisting of RCGS that was rolled before ensiling in a roller mill mounted in a bagging machine (2.18 mm geometric mean particle size). Diet ingredients were mixed manually twice daily, at 09:00 and 15:00 h, and offered as total mixed rations in amounts approximately 50 g/kg in excess of daily intake. The experimental diets contained a forage:concentrate ratio of 130:870 g/kg, with 644 g/kg of RCGS. The GRC resulted in greater daily variation in dry matter intake, total-tract digestibility (dry and organic matter), fecal pH, rumen papillae width, and lower first meal duration, meal length, fecal starch, and rumen papillae height than the RRC. However, grinding or rolling RCGS did not affect dry matter intake, growth performance, carcass traits, or health (liver abscesses, ruminitis, serum D-lactate) of finishing beef cattle. Therefore, the processing equipment to make RCGS might be preferable based on equipment availability, milling yield, energy consumption, and diet composition.(AU)

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The aim of this study was to evaluate the effect of the type of calving (normal or assisted) on the occurrence of puerperal uterine disorders and on the number of artificial inseminations (AI) per conception and pregnancy rate at 150 days postpartum (PPD). Cows were observed during parturition and the type of calving was classified as normal or assisted. Normal calving required no human interference, while assisted calving required a calf removal aid via vaginal access. There were 825 births, 7 stillbirths (0.85%) and 17 twins (2.06%). We analyzed 801 single births, from which 766 (95.63%) were normal and 35 (4.36%) assisted. Were evaluated the uterine disorders occurrence such as retained placenta combined with metritis (PR/ME) and clinical endometritis (CE). The overall occurrences were 10.24% (82/801) of RP/ME, 12.86% for CE and 5.12% for RP/ME and CE. Most of normal calving cows had healthy puerperium (73.89%), whereas a majority of assisted calving cows had uterine disorders (74.29%). The number of AI per conception was similar for cows that had either normal or assisted calving (2.39±0.08 and 3.00±0.43, P = 0.16). There was no evidence of negative influence of calving type on the 150 PPD pregnancy rate of lactating crossbreed dairy cows (P = 0.44). Healthy cows had higher 150 PPD pregnancy rate than cows affected by puerperium uterine disorders (51.65 vs. 42.92%). Normal calving crossbred dairy cows had a healthier puerperium, compared to cows with assisted calving which were more susceptible to puerperium uterine disorders. And cows with a health puerperium have a higher pregnancy rate at 150 days postpartum.

Objetivou-se avaliar em vacas leiteiras mestiças que pariram um bezerro vivo, o efeito do tipo de parto (normal ou assistido) na ocorrência de desordens uterinas puerperais e no número de inseminações artificiais (IA) por concepção e taxa de prenhez 150 dias pós-parto (DPP). As vacas foram monitoradas durante o parto e o tipo de parto foi classificado como normal ou assistido. O parto normal não precisou de interferência humana, enquanto o parto assistido precisou de auxílio para retirada do bezerro por via vaginal. Foram registrados 825 partos, sendo 7 natimortos (0,85%) e 17 gemelares (2,06%). Foram analisados 801 partos simples, dos quais 766 (95,63%) foram normais e 35 (4,36%) foram assistidos. Foram avaliadas a ocorrência de desordens uterinas como a retenção de placenta associada com metrite (RP/ME) e endometrite clínica (EC). A ocorrência das doenças foi de 10,24% (82/801) para RP/ME, 12,86% para EC e 5.12% para RP/ME com CE. A maioria das vacas com parto normal tiveram puerpério saudável (73,89%), enquanto a maioria das vacas com parto assistido apresentaram desordens uterinas (74,29%). O número de IA por concepção foi semelhante nas vacas que tiveram parto normal ou assistido (2,39±0,08 e 3,00±0,43, P = 0,16). Não houve evidência de influência negativa do tipo de parto na taxa de prenhez 150 DPP de vacas leiteiras mestiças em lactação (P = 0,44). Vacas saudáveis apresentaram maior taxa de prenhez 150 DPP do que vacas afetadas por desordens uterinas no puerpério (51,65 vs. 42,92%). Vacas leiteiras mestiças com parto normal tiveram um puerpério saudável, comparadas às que tiveram parto assistido, por sua vez foram mais susceptíveis as desordens uterinas no puerpério. E vacas com puerpério saudável resultaram em maiores taxas de prenhez aos 150 dias pós parto.

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This study aimed to evaluate the ingestive behavior of F1 Holstein × Zebu cows grazing on deferred pasture receiving different supplementation strategies. The experimental design was completely randomized, in a 3×4 factorial, with three supplementation strategies and four evaluation periods. The ingestive behavior of 24 cows divided into three groups of supplementation provided at milking was observed, and two of these groups received protein in the pasture. Ingestive behavior was monitored every 10 minutes for 24 hours and analyzed in the form of periods (morning, afternoon, night, and dawn) and total time. The animals remained longer grazing during the afternoon when the BGHI presented values of 83.8. Protein consumption did not influence grazing time but interfered with forage consumption. For the total grazing time, the animals in group 2 spent less time grazing. The groups of animals presented no difference concerning the time spent on rumination and idleness. During night and dawn, when the climate was characterized as thermal comfort, the animals spent more time ruminating. The climatic conditions did not influence the ingestive behavior, as the grazing peak was observed at times of higher BGHI. However, supplementation of the animals in group 2 modified the ingestive behavior of F1 H × Z cows.

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The objective of this study was to analyze the correlation between milking characteristics and the behavior of cows in automatic milking systems. Data were collected between September 2019 and March 2020 from two commercial dairy herds located in Minas Gerais, Brazil, which use an automatic milking system (AMSTM, DeLaval, Tumba, Sweden). The dataset comprised 68,896 observations from 542 primiparous and multiparous cows of Holstein and crossbred (Holstein × Jersey) breeds. Daily milking characteristics, including milk flow rate (FR), time spent in the milking box (BT), and milking efficiency (ME), were recorded, along with behavioral traits such as milking handling time (HT), incomplete milkings (IM), and kicks. To assess the relationships between these traits, a bivariate correlation analysis was performed using Pearson's correlation coefficient, executed with the statistical software SPSS version 22. The results revealed moderate negative correlations between FR and BT, ME and HT, and BT and ME. Conversely, a strong positive correlation was observed between FR and ME. A high positive correlation was identified between BT and HT, a moderate positive correlation between ME and milk yield, and a weak positive correlation between HT and IM (P<0.01). No significant correlation was found between milking frequency and kicks or incomplete milkings.(AU)

Objetivou-se analisar a correlação entre características de ordenhabilidade e de comportamento de vacas ordenhadas em sistemas de ordenha automáticas. Os dados coletados, foram referentes ao período de setembro de 2019 a março de 2020, oriundos de dois rebanhos leiteiros comerciais localizados no Estado de Minas Gerais, nos quais utilizam sistema de ordenha automática (AMSTM, DeLaval, Tumba, Suécia), contêm 68.896 observações, de 542 vacas primíparas e multíparas da raça Holstein e mestiças (Holstein x Jersey). Os registros diários de características de ordenhabilidade como fluxo do leite (FL), tempo no box (TB) e eficiência na ordenha (EO); bem como características de comportamento: handling time na ordenha (HT), ordenhas incompletas (OIN) e coices (COI) foram avaliadas por análise de correlação bivariada pelo coeficiente de correlação de Pearson, utilizando-se o programa estatístico SPSS versão 22. As correlações foram negativas moderadas entre FL e TB; EO e HT; bem como TB e EO; e positiva e alta entre FL e EO. Correlação positiva e alta foi encontrada entre TB e HT; positiva e moderada entre EO e PL; e positiva baixa entre HT e OIN (P<0,01). Não houve correlação entre a frequência de ordenha (FO) com COI e OIN.(AU)

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This study aimed to evaluate the efficiency of a body condition score (BCS) assessment device (BCAD) to identify cows with an adequate BCS and, presumably, a higher fertility when subjected to timed artificial insemination (TAI). We evaluated cows at smallholder dairy farms in the state of Rondonia, Brazil. Crossbred dairy cows (n = 141) were subjected to a TAI protocol and classified according to the BCAD scale as low BCS (red; n = 55) or adequate BCS (green; n = 86). The outcome pregnancy per artificial insemination (P/AI) was analyzed by logistic regression. Cows classified as green by the BCAD had a significantly greater P/AI (41 of 86; 47.7%) than cows classified as red (15 of 55; 27.3%; P = 0.01). In conclusion, the BCS assessment device was an effective tool to detect cows more likely to become pregnant due to their adequate BCS and, consequently, better fertility in TAI.

Este estudo investigou a eficiência de um dispositivo avaliador de ECC (escore de condição corporal) (DAEC) para identificar vacas com ECC adequado e, presumivelmente, com fertilidade mais alta quando submetidas a protocolos de inseminação artificial em tempo-fixo (IATF). Conduzimos o estudo em pequenas propriedades leiteiras no estado de Rondônia, Brasil. Vacas leiteiras mestiças (n = 141) foram submetidas a um protocolo de IATF e classificadas de acordo com a escala do DAEC em vacas com ECC baixo (vermelho; n = 55) ou ECC adequado (verde; n = 86). A prenhez por inseminação artificial (P/IA) foi analisada por regressão logística. Vacas classificadas como verde no DAEC apresentaram P/IA significativamente mais alto (41 de 86; 47,7%) que vacas classificadas como vermelho (15 de 55; 27,3%; P = 0,01). Conclui-se que o dispositivo avaliador de ECC é uma ferramenta eficiente para detectar vacas com adequado ECC e com consequente maior fertilidade na IATF.

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Milk's qualitative and technological properties are greatly affected by genetic polymorphisms in the kappa-casein gene, and their polymorphisms may serve as informative markers of yield and composition. Thus, the objective of this study was to detect kappa-casein (kappa-CN) gene polymorphisms and their association with milk production traits in crossbred dairy cows. One hundred healthy crossbred (Friesian x Jenoubi) dairy animals between three and five years old were sampled for blood and milk during their first lactation. The genomic DNA was extracted from whole blood, and restriction fragment length polymorphism (RFLP-PCR) was used to determine the genotype of the kappa-CN gene. As a consequence of the restriction digestion of this fragment with Hind III, it showed three different restriction patterns: BB (453 base pairs uncut), AB (453, 206, and 225 base pairs), and AA (206 and 225 base pairs). Based on genetic diversity, the AB genotype was the most predominant (n = 67), with a frequency of 0.67. A variant genotype of the kappa-CN gene was associated with milk production traits in crossbred dairy cows. Animals with the AA variant produced a higher milk yield and a higher percentage of fat, casein, protein, and solids not fat (SNF) (P≤0.05) (1.397kg, 0.75%, 0.31%, 0.27%, and 0.68%, respectively) than those with the BB variant. A logistic regression analysis confirmed that the kappa-CN genotypes increase milk yield and casein content. Therefore, genetic variants of the kappa-CN gene could be used as genetic markers for improving milk production traits in dairy cattle.(AU)

As propriedades qualitativas e tecnológicas do leite são muito afetadas por polimorfismos genéticos no gene kappa-caseína e esses polimorfismos podem servir como marcadores informativos de rendimento e composição. Assim, o objetivo deste estudo foi detectar polimorfismos do gene kappa-caseína (kappa-CN) e sua associação com características de produção de leite em vacas leiteiras mestiças. Cem animais mestiços (Freisian x Jenoubi) saudáveis, entre três e cinco anos de idade, foram amostrados durante a primeira lactação para sangue e leite. O DNA genômico foi extraído do sangue total e o polimorfismo dos fragmentos de restrição do DNA genômico (RFLP-PCR) foi usado para determinar o genótipo do gene kappa-CN. Em consequência da digestão de restrição deste fragmento com Hind III, ele apresentou três padrões de restrição diferentes: BB (453 pares de bases não cortadas), AB (453,206 e 225 pares de bases) eAA (206 e 225 pares de bases). Com base na diversidade genética, o genótipo AB foi o mais predominante (n = 67), com frequência de 0,67. Genótipo variante do gene kappa-CN foi associado com características de produção de leite em vacas leiteiras mestiças. Animais com a variante AA tiveram maior produção de leite e maior percentual de gordura, caseína, proteína e sólidos não gordurosos (SNG) (P≤0,05) (l,397kg, 0,75%, 0,31%, 0,27% e 0,68%, respectivamente) do que aqueles com variante BB. Uma análise de regressão logística confirmou que os genótipos kappa-CN aumentam a produção de leite e o teor de caseína. Portanto, variantes genéticas do gene kappa-CN podem ser usadas como marcadores genéticos para melhorar as características de produção de leite em bovinos leiteiros.(AU)

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Retained placenta, metritis, and clinical endometritis are prevalent diseases on dairy farms; they lead to economic losses and reduce the longevity of dairy cows in dairy production systems. Hence, it is important to investigate potential predisposing factors. The aim of this study was to evaluate the relationship between perineal hygiene during calving and the incidence of retained placenta, metritis, and clinical endometritis, and their effect on reproductive efficiency in crossbred dairy cows. At two farms, pre-calving cows (n = 101) were evaluated for perineal dirtiness before calving by visual observation. They received a score of 1, free of feces and a dry perineum; a score of 2, slight presence of feces and a moist perineum; or a score of 3, a mild-wet perineum covered by feces (over 10% of the surface). After calving, cows were subjected to visual observation and gynecological evaluation to identify retained placenta, metritis, and clinical endometritis. Cows with a hygiene score of 2 or 3 showed higher rates of retained placenta (41.9% vs. 14.0%, P = 0.0049), metritis (32.5% vs. 14.0%, P = 0.0191), and clinical endometritis (42.5% vs. 15.8%, P = 0.0061) compared with cows with a score of 1. There were no effects on reproductive efficiency. The findings indicate that the degree of perineal dirtiness in prepartum crossbred dairy cows is associated with the occurrence of uterine puerperal disorders.(AU)

Retenção de placenta, metrite e endometrite clínica são distúrbios presentes nas fazendas leiteiras, levando a perdas econômicas e reduzindo a longevidade das vacas nos sistemas de produção, dessa forma, é importante investigar os possíveis fatores predisponentes. Objetivou-se avaliar a relação entre higiene perineal antes do parto e a ocorrência de retenção de placenta, metrite, endometrite clínica e sua influência na eficiência reprodutiva de vacas leiteiras mestiças. Em duas propriedades, vacas no pré-parto (n=101) foram avaliadas quanto ao grau de sujidade perineal antes do parto, por observação visual e classificadas em escore 1 - livre de fezes e períneo seco; escore 2 - presença sutil de fezes e períneo úmido; escore 3 - períneo moderadamente molhado, coberto por fezes (acima de 10% da superfície). Após o parto, as vacas foram avaliadas por observação visual e avaliação ginecológica para diagnosticar retenção de placenta, presença de metrite e endometrite clínica. Vacas com escores de higiene 2 ou 3 tiveram maior incidência de retenção de placenta (41,9% x 14,0%, P = 0,0049), metrite (32,5% x 14,0%, P = 0,0191) e endometrite clínica (42,5% x 15,8%, P = 0,0061) se comparadas a vacas com escore 1. Não foram observados efeitos na eficiência reprodutiva. Esses achados indicam que o grau de sujidade perineal de vacas leiteiras mestiças no pré-parto está relacionado com a ocorrência de desordens uterinas pós-parto.(AU)

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The objective of this study was to analyze the correlation between milking characteristics and the behavior of cows in automatic milking systems. Data were collected between September 2019 and March 2020 from two commercial dairy herds located in Minas Gerais, Brazil, which use an automatic milking system (AMSTM, DeLaval, Tumba, Sweden). The dataset comprised 68,896 observations from 542 primiparous and multiparous cows of Holstein and crossbred (Holstein × Jersey) breeds. Daily milking characteristics, including milk flow rate (FR), time spent in the milking box (BT), and milking efficiency (ME), were recorded, along with behavioral traits such as milking handling time (HT), incomplete milkings (IM), and kicks. To assess the relationships between these traits, a bivariate correlation analysis was performed using Pearson's correlation coefficient, executed with the statistical software SPSS version 22. The results revealed moderate negative correlations between FR and BT, ME and HT, and BT and ME. Conversely, a strong positive correlation was observed between FR and ME. A high positive correlation was identified between BT and HT, a moderate positive correlation between ME and milk yield, and a weak positive correlation between HT and IM (P<0.01). No significant correlation was found between milking frequency and kicks or incomplete milkings.(AU)

Objetivou-se analisar a correlação entre características de ordenhabilidade e de comportamento de vacas ordenhadas em sistemas de ordenha automáticas. Os dados coletados, foram referentes ao período de setembro de 2019 a março de 2020, oriundos de dois rebanhos leiteiros comerciais localizados no Estado de Minas Gerais, nos quais utilizam sistema de ordenha automática (AMSTM, DeLaval, Tumba, Suécia), contêm 68.896 observações, de 542 vacas primíparas e multíparas da raça Holstein e mestiças (Holstein x Jersey). Os registros diários de características de ordenhabilidade como fluxo do leite (FL), tempo no box (TB) e eficiência na ordenha (EO); bem como características de comportamento: handling time na ordenha (HT), ordenhas incompletas (OIN) e coices (COI) foram avaliadas por análise de correlação bivariada pelo coeficiente de correlação de Pearson, utilizando-se o programa estatístico SPSS versão 22. As correlações foram negativas moderadas entre FL e TB; EO e HT; bem como TB e EO; e positiva e alta entre FL e EO. Correlação positiva e alta foi encontrada entre TB e HT; positiva e moderada entre EO e PL; e positiva baixa entre HT e OIN (P<0,01). Não houve correlação entre a frequência de ordenha (FO) com COI e OIN.(AU)

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Crossbred cattle are used in dual-purpose systems to obtain meat and milk, becoming one of Colombia's systems with the greatest presence. However, studies characterizing productive variables in crossbred individuals are scarce, making it pertinent to conduct analyses evaluating their potential. The objective of this study was to phenotypically characterize a population of crossbred cattle from the state of Norte de Santander (Colombia) in terms of milk traits. Up to a maximum of 4 controls per female was obtained, and information on milk yield (MY), fat percentage (FP), protein percentage (PP), and somatic cell count (SCC) of first parity crossbred females was evaluated. The information was filtered and analyzed with the R program. The mean, standard deviation, and general variation coefficient were calculated for each trait and the means and deviations by non-genetic categorical factors. For the numeric factors, graphs of trends related to the response variables were made. Multiple correspondence analysis was performed, and the standardized residual values were estimated to recognize associations between levels of non-genetic factors and each trait. Mean values for controls were: 3.06±1.40 kg/day (MY), 3.21±0.40% (PP), 3.32±0.77% (FP), and 357±256x103cells/ml (SCC). The non-genetic factors that showed the most significance were the pasture type, the control season, and the region. Thus, MY from 1.00 to 2.00 kg is associated with the levels of region 1 (R1) and summer 1 (S1), MY from 2.10 to 3.99 kg with region 2 (R2), group 1 (G1) and winter 1 (W1), MY from 4.00 to 8.30 kg with R1, group 3 (G3) and W1, PP from 2.45 to 2.99% there was association with G1, PP from 3.00 to 3.40% with group 2 (G2), PP from 3.41 to 6.04% with G3, FPof 1.94 to 3.00% is associated with R1, G3, S1, and S2, FP of 3.01 to 4.00% with R2, G1 and W1, FP from 4 to 4.82 % with region 3 (R3), G2, and S1, SCC from 8.00 to 100x103cells/ml is associated with R1, R3, and S1, SCC of 101 to 499x103cells/ml with R2, G1, and W1. Finally, SCC of 500 to 888x103cells/ml is associated with R2 and W1. A variation of medium to high magnitude of the traits evaluated within the population was evidenced, revealing that no standards that allow unifying the management of animals within herds, which can affect the efficiency of dual-purpose systems.(AU)

O gado cruzado é utilizado nos sistemas de dupla aptidão procurando se obter carne e leite; este é o sistema produtivo bovino com maior representação na Colômbia. Estudos de caracterização de variáveis produtivas em indivíduos cruzados são escassos, tornando, pertinente realizar análises que avaliem o seu potencial. Objetivou-se caracterizar fenotipicamente uma população de gado cruzado no estado de Norte de Santander (Colômbia), considerando características relacionadas com a produção de leite. Foram obtidos até um máximo de 4 controles por fêmea e avaliadas informações sobre produção de leite (MY), porcentagem de gordura (FP), porcentagem de proteína (PP) e contagem de células somáticas (SCC) de fêmeas cruzadas de primeira ordem de parto. A informação foi depurada e analisada com o programa R. Foi calculada a média, desvio padrão e coeficiente de variação para cada característica de maneira geral e detalhando por fatores categóricos não genéticos. Para os fatores numéricos foram elaborados gráficos de tendencias relacionados com as variáveis resposta. Realizou-se uma análise de correspondência múltipla e estimados os valores dos resíduos padronizados para reconhecer níveis de fatores não genéticos com influência sobre as características. Os valores médios para os controles foram: 3.06±1.40 kg/dia (MY), 3.21±0.40% (PP), 3.32±0.77% (FP), e 357 ± 256x103células/ml (SCC). Os fatores não genéticos que apresentaram maior influência foram o tipo de pastagem, a estação de controle e a região. Assim, a MY de 1,00 a 2,00 kg está associada aos níveis da região 1 (R1) e verão 1(S1), a MY de 2,10 a 3,99 kg à região 2 (R2), grupo 1 (G1) e inverno 1 (W1), EM de 4,00 a 8,30 kg com R1, grupo 3 (G3) e W1, PP de 2,45 a 2,99% foi associado ao G1, PP de 3,00 a 3,40% ao grupo 2 (G2), PP de 3,41 a 6,04% ao G3 , FP de 1,94 a 3,00% está associado a R1, G3, S1 e S2, FP de 3,01 a 4,00% a R2, G1 e W1, FP de 4 a 4,82% à região 3 (R3), G2 e S1, SCC de 8,00 a 100x103células/ml está associado a R1, R3 e S1, SCC de 101 a 499x103células/ml a R2, G1 e W1. Finalmente, SCC de 500 a 888x103células/ml estão associadas a R2 e W1. Foi evidenciada uma variação de média a alta magnitude das características avaliadas dentro da população, revelando que não existem padrões que permitam unificar o manejo dos animais dentro dos rebanhos, o que pode afetar a eficiência dos sistemas de dupla aptidão. Foi evidenciada uma variação de magnitude média a alta das características avaliadas dentro da população, revelando que não existem padrões para unificar o manejo dos animais dentro das fazendas, o que pode influenciara eficiência dos sistemas de dupla aptidão.(AU)

Resumo

The objective of this study was to evaluate the seasonal effect of months of the year upon the physiological and productive responses of crossbred dairy cows raised in an Amazonian climate. Twenty lactating cows were evaluated, fed on Brachiaria decumbens pasture, with free access to water and mineral supplementation. Data from climate variables air temperature (AT), relative humidity (RH), rainfall (RA) and temperature and humidity index (THI) were recorded dur ing the months of January to April 2019. The physiological data collected were: respiratory rate (RR, mov/min), heart rate (HR, beats/min), rectal temperature (RT, ºC), udder surface temperature (UST, ºC), body surface temperature (BST, ºC), dorsum surface temperature (DST, ºC), front surface temperature (FST, ºC) and rear shin temperature (RST). Milk production (MP) was also measured. There was a significant difference (P<0.05) of RST and RR with values ranging from 34.8 to 35.5°C and 32.0 to 36.2 mov/min, respectively. There were no significant difference (P>0.05) for BST, and the values for MP and THI were 3.8; 3.8; 4.6; 4.1 kg and 77.7; 79.7; 80.6; 80.1, respectively. It was concluded that there was a seasonal effect of the months of the year evaluated on the respiratory rate of animals, however, it did not change the MP and the THI. The Amazon environment is conducive to causing thermal stress in lactating cows raised on pasture, requiring the use of shading to facilitate the ability of these animals to dissipate heat.(AU)

O objetivo desse estudo foi avaliar os efeitos sazonais dos meses do ano sobre as respostas fisiológicas e produtivas de vacas leiteiras mestiças criadas em clima amazônico. Foram avaliadas 20 vacas lactantes, alimentadas com pasto de Brachiaria decumbens, com acesso livre a água e suplementação mineral. Foram registrados dados das variáveis climáticas temperatura do ar (TA), umidade relativa do ar (UR), precipitação pluviométrica (PP) e índice de temperatura e Umidade (ITU) durante os meses de janeiro a abril de 2019. Os dados fisiológicos coletados foram: frequência respiratória (FR, mov/min), frequência cardíaca (FC, bat./min), temperatura retal (TR, ºC), temperatura superficial do úbere (TSU, ºC), temperatura superfície corporal (TSC, ºC), temperatura superficial do dorso (TSD, ºC), temperatura superficial da fronte (TSF, ºC) e temperatura superficial da canela (TSCA, °C). Também foi mensurada a produção de leite (PL, kg). Houve diferença significativa (P<0,05) da TSCA e FR com valores variando de 34,8 a 35,5°C e 32,0 a 36,2 mov/min, respectivamente. Não houve diferença significativa (P>0,05) para TSC e os valores observados para PL e ITU foram 3,8; 3,8; 4,6; 4,1 kg e 77,7; 79,7; 80,6; 80,1, respectivamente. Houve efeito sazonal dos meses avaliados sobre a taxa respiratória dos animais, no entanto, isso não alterou a PL nem o ITU. O ambiente amazônico é propício a causar estresse térmico em vacas lactantes mantidas a pasto, sendo necessário o uso de sombreamento para facilitar a capacidade de dissipação de calor corporal desses animais.(AU)

Resumo

The complete rearing cycle of dairy calves is not yet widely adopted by rural producers, possibly because they do not perceive these animals as potential meat producers or are unaware of their production capabilities. This study aimed to assess the economic viability of rearing dairy calves through their entire growth cycle. Sixteen Holstein × Gyr crossbred animals were assessed, originating from dairy farming, with an average initial weight of 40.67 ± 5.27 kg and slaughtered at 10 months of age, reaching a final weight of 320.4 ± 45.87 kg. These calves were reared in a feedlot system and received a mash diet without the inclusion of roughage. The experiment was conducted on a farm primarily focused on dairy farming, situated in the municipality of Turvânia, GO, Brazil. Economic evaluations were conducted at the conclusion of the production cycle, with the calculation of the value of the arroba (@ = 15 kg) produced. Data were analyzed using a production cost structure methodology, which included effective operating cost, total operating cost, and total cost. The following economic indicators were examined: gross revenue, gross margin, net margin, and the break-even point. Results were highly promising, demonstrating a profit from raising dairy male calves, with a net margin per animal of BRL 321.50. Additionally, these animals displayed noteworthy potential for weight gain and carcass quality. A total of 149.19 @ were produced, averaging 9.32 @ per animal, with a production cost of BRL 105.52, encompassing expenses such as milk consumption, concentrate diet, and labor, which amounted to BRL 1.18 per month per animal. These findings underscore the economic feasibility of this rearing system.(AU)

O ciclo completo de bezerros leiteiros ainda não é muito utilizado pelos produtores rurais, por não considerarem esses animais como produtores de carne, ou pelo motivo de não conhecerem o potencial de produção. Objetivou-se avaliar os índices econômicos do ciclo completo em bezerros leiteiros. Foram avaliados 16 animais mestiços Holandês x Gir, oriundos da atividade leiteira com peso médio inicial de 40,67 ± 5,27 kg, abatidos aos 10 meses de vida com peso final de 320,4 ± 45,87 kg, mantidos em sistema de confinamento recebendo dieta farelada sem o uso de volumoso. O experimento foi conduzido em uma propriedade com principal fonte renda à atividade leiteira, no munícipio de Turvânia-GO. As avaliações econômicas foram feitas no final do ciclo de produção, com o cálculo do valor da arroba (@) produzida, para a interpretação dos dados utilizou-se a metodologia da estrutura de custos de produção: custo operacional efetivo, custo operacional total e custo total. Foram analisados os seguintes indicadores econômicos: receita bruta, margem bruta, margem líquida e ponto de equilíbrio. Os resultados obtidos foram satisfatórios, ao apresentarem lucro com utilização dos machos leiteiros, com Margem Líquida por animal de R$ 321.50, além do potencial de ganho de peso e qualidade de carcaça desses animais. Foram produzidas 149,19 @ com média de 9,32 @ animal-¹, com o custo de produção de R$ 105,52 incluindo o leite consumido, dieta concentrada e a mão-de-obra no valor de R$ 1,18 ao mês por animal, demonstrando viabilidade econômica do sistema.(AU)

Resumo

The present study aimed at assessing the effects of hepatoprotective agents in diets that contain sources of energy on milk production, milk composition, and nutrient partition in lactating cows. Sixteen Holstein x Gir crossbred mid-lactation cows with an average body weight of 553 ± 85 kg were used in this study. These animals were allocated in a 4x4 Latin square design. A 2x2 factorial arrangement was employed in this feeding experiment. In each treatment, cows received diets with or without a hepatoprotective agent and variable in ground corn grain or citrus pulp as energy sources. Evaluated parameters included nutrient intake and digestibility, milk production, milk composition, energy balance, and nitrogen balance. Performance and nutrient balance variables were assessed and no interaction was observed between the hepatoprotective compounds and the dietary sources of energy. Dry matter intake, milk production and net energy for lactation were higher in corn as an energy source whereas milk fat content was higher in citrus pulp diets. There was a reduction in protein and casein contents in the milk of cows that was supplemented with an hepatoprotective agent. In this study, the hepatoprotective agent improved nitrogen balance in dairy cows. The use of the hepatoprotective compounds in the diet of these lactating cows in confinement reduced the milk protein fraction and favored a higher nitrogen balance in these animals. Retention of nitrogen compounds in the metabolism of lactating cows under confinement is influenced by hepatoprotective agents.(AU)

Objetivou-se com este estudo avaliar os efeitos de fontes de energia associadas a um hepatoprotetor sobre a produção, composição do leite e a partição dos nutrientes em vacas lactantes confinadas. Foram utilizadas 16 vacas mestiças Holandês x Gir no terço médio da lactação, com peso corporal médio de 553 ± 85 kg, distribuídas em delineamento experimental quadrado latino 4x4 quádruplo em arranjo fatorial 2x2. Os tratamentos consistiram de dieta com ou sem a inclusão do hepatoprotetor, e variação de milho moído ou polpa cítrica como fontes de energia. Não houve interação (P>0.05) entre as fontes de energia e o hepatoprotetor para as variáveis de desempenho e balanço de nutrientes. O consumo de matéria seca, a produção de leite, o leite corrigido para 4% de gordura foram maiores (P<0.05) nas dietas com milho moído como fonte de energia. O teor de gordura do leite foi maior (P<0.05) nas dietas com a polpa cítrica. Houve redução (P<0.05) no teor de proteína bruta e caseína no leite das vacas que receberam o hepatoprotetor na dieta. O hepatoprotetor favoreceu maior (P<0.05) retenção e balanço de nitrogênio nas vacas. Portanto, o milho moído pode ser utilizado na dieta como fonte de energia para impulsionar a produção de leite. Enquanto, a fonte de energia proveniente da polpa cítrica afeta a composição do leite, através do incremento no teor de gordura. O uso de hepatoprotetores na dieta favoreceu maior retenção de nitrogênio em vacas lactantes confinadas.(AU)