Lactation performance, feed efficiency, and blood metabolites of dairy cows treated with recombinant bovine somatotropin: A systematic review and meta-analysis.

A systematic review and meta-analysis were conducted to assess the impact of recombinant bovine somatotropin (rbST) on lactation performance, feed efficiency, and blood metabolites in dairy cows. In the systematic review, articles were selected based on the following criteria: (1) Data focusing on the influence of bovine somatotropin doses on milk production; (2) Submission of original data; (3) Articles published in journals; and (4) Articles in English or Portuguese. The analysis of variance was used with a completely randomized design and mixed models methodology. Polynomial regression was applied to significant fixed effects (rbST dose). The use of rbST resulted in increased milk yield and 4% fat-corrected milk yield, while fat, protein, and lactose contents remained unaffected. Dry matter and metabolizable energy intakes, as well as milk/feed efficiency, exhibited a linear increase, but body condition score (BCS) was negatively impacted. The administration of rbST led to higher blood concentrations of triglycerides and insulin. Cows treated with rbST showed a 23% increase in non-esterified fatty acid (NEFA) concentrations compared to non-treated cows. Additionally, growth factors IGF-1 and IGF-2 displayed a linear increase with rbST treatment. In summary, rbST administration increased milk yield and fat-corrected milk yield without affecting milk components. However, despite increasing intake, it resulted in BCS losses and alterations in blood parameters such as NEFA, IGF-1, and IGF-2.

Factors intrinsic to handling and transport in pre-slaughter behavioural changes in beef cattle.

The aim of this study was to evaluate handling and transport variables as potential causes of disturbed behaviour in response to seeing a person on an overhead observation platform during pre-slaughter in batches of females and castrated males composed of pure or crossed Bos Taurus animals (Aberdeen Angus, Red Angus, Hereford and Charolais) with a maximum of 37.5% Bos indicus, and maturity at slaughter varying from zero to eight teeth, coming from pasture and confined systems. For the batches of castrated males, the independent variables included the distance covered on the trip, and the handling and facilities on the farms. For the female batches, the variables were travel time and waiting time prior to unloading. For both sexes, the presence of horns in the batches and the load density were included in the regression equations. Disturbed behaviour, the result of factors related to animal handling and transportation, is detrimental to satisfactory results in production systems. It is up to the managers in the production chain to seek alternatives in order to minimise inappropriate behaviour, which is one determinant of loss. Handling and transport are determining factors in the behaviour of beef cattle during the pre-slaughter period.

Trade and consumption of buffalo meat in Brazil.

Due to the lack of information concerning the buffalo production chain, the aim of this survey was to identify consumer behaviour, acceptance and trends in relation to buffalo meat. The survey research method was used, for which an online questionnaire was prepared using Google Forms, and distributed via digital platforms to Brazilian consumers. Using the exploratory technique of multivariate statistics, ordination was carried out by principal component analysis (PCA), where the words were grouped into dimensions. Of the respondents, 44.82% had already consumed buffalo meat; however, many did not know whether they had already tried it, since 50.24% of the respondents said they could not identify any difference between buffalo meat and beef. An identification and indication of the origin were considered important by 44.82% of respondents. The respondents cited 1130 different terms, the word 'quality' appearing in most responses. Principal component analysis explained 93.32% of the variations in the consumer perception of buffalo meat. A part of Brazilian consumers is unaware of the buffalo production chain, and have never had the opportunity to consume the meat. The creation and divulgation of a certificate of identification, together with the benefits to health from consuming buffalo meat is fundamental for consumer confidence, which, together with the ready availability of the product, would allow expansion, consolidation and improvement of the production chain. The results of the study show the potential for increasing the consumption of buffalo meat among Brazilian consumers, providing the product included a guarantee of origin, quality and healthiness.

Environmental factors on the probability of pregnancy in early or conventionally weaned beef cows.

Potential variables for the reproductive success of beef cows were evaluated. Included in the model were the age of the cow at calving; the interval between the Julian calving date and the end of the breeding season; the body weight and conditions at calving, at 75 days post-partum and at the end of the breeding season; and the mean daily variation in weight between these dates. Logistic regression was used in the analysis, with the parameters evaluated using the odds ratio statistic, estimating the chance of pregnancy. The mean rate of pregnancy was 84% and 55% for early and late-weaned cows, respectively. For early weaned cows, the regression variables were the Julian calving date, age of the cow, weight gain from calving to 75 days post-partum, and from 75 days post-partum to the end of the reproductive period. For late-weaned cows, there were only two regression variables, weight at calving and weight gain from calving to the end of the reproductive period. For every year above the average age of the herd, early weaned cows have an 80.9% greater chance of pregnancy, while a reduction of one year reduces the chance of pregnancy by 44.7%. In early weaned cows, every seven days after the mean Julian calving date reduces the chances of pregnancy by 22.6%, whereas every seven days before the mean calving date increases pregnancy by 29.2%. Greater gains in cow body weight, from calving to the end of the reproductive period, determine a greater probability of pregnancy.

Carcass traits and meat quality of lambs slaughtered during different seasonal conditions.

This study was conducted to evaluate the effects of slaughtering feedlot Texel lambs during different climatic conditions on carcass and meat quality traits. Twenty castrated male Texel lambs (21.8 ± 0.62 kg) were distributed to two treatments according to the climatic conditions during the finishing period and at pre-slaughter: warm season (WS; mean temperature of 23.4 °C and 77.5% relative humidity) and cool season (CS; mean temperature of 14.9 °C and 79.5% relative humidity). During the pre-slaughter, thermal comfort was evaluated through the variables: respiratory frequency, rectal temperature, temperature of the ocular region, and temperature-humidity index (THI). After the finishing period, lambs were slaughtered, and carcass and meat quality traits were assessed. The THI values indicate that animals harvested in the WS spent 13 h of the day under potential thermal discomfort conditions in the week before slaughter and in the pre-slaughter period, whereas lambs harvested in the CS did not experience any thermal discomfort. Slaughter weight, carcass weight, carcass dressing, and backfat thickness were greater (P ≤ 0.03), whereas cooling losses were lower (P < 0.01) for lambs slaughtered in the CS. Moreover, thawing losses were lower (P < 0.01), whereas cooking losses were greater (P < 0.01) for lambs harvested in the CS. Lambs slaughtered in the CS also showed greater meat redness, yellowness, and chroma values (P < 0.05). Although carcass traits were affected by the greater thermal discomfort exposure, meat quality of lambs was less impacted by the climatic conditions at slaughter.

Body mass index at calving on performance and efficiency of Charolais cow herds.

This study evaluated the productive and reproductive performance of Charolais cows with different body mass index (BMI) at calving and the development of their calves. Seventy-two Charolais cows and their calves were grouped into BMI classes at calving, namely, low, moderate, and high. Body mass index was determined by dividing the cows' body weight by their body length and hip height and finally dividing the result by 10. Cows and their calves were weighed immediately after calving, at early weaning (63-day postpartum), and at pregnancy diagnosis (210-day postpartum). To evaluate milk production and quality, collections were performed at 21, 42, and 63 days after calving. Cows with high and moderate BMI were heavier (P < 0.05) than low-BMI cows from calving to the date of pregnancy diagnosis. Calves from low-BMI cows were heavier (P < 0.05) at 210-day postpartum than those born to cows with moderate and high BMI. The low- and moderate-BMI cows had higher pregnancy rates than those with a high BMI and were more efficient (P < 0.05) at calving and at weaning in kilograms of calf produced per kilogram of cow kept in the herd. High- and moderate-BMI cows had the highest milk production, whereas low-BMI cows produced milk with the highest concentrations of lactose and solids-not-fat (P < 0.05). Charolais cows with low and moderate BMI at calving are more efficient in production systems. The BMI may be considered a selection variable to improve the productive results of breeding herds.

Morphophysiology of forage peanut submitted to different intensities of defoliation on grazing with sheep.

The aim was to monitor the growth, the dry mass accumulation curve, and the structural photosynthetic components of forage peanut pasture, in different intensities of defoliation in sheep rotational stocking. Experimental area of Arachis pintoi (cv. Amarillo) had 0.29 ha divided equally into 16 paddocks of 180 m2 where they were assigned in a randomized block design with four repetitions; intensities of grazing were very lenient, lenient, moderate, and severe, represented by the residue heights of 11.2, 8.4, 5.9, and 3.2 cm respectively, from 14 cm (pre-grazing height). Weekly evaluations were carried out in the remaining period and in the pre and post-grazing period, with the forage cut to soil level for the determination of the dry mass available, separation of the structural components of pasture, and determination of the area of the leaflets. From this information, the values of leaf area index, leaf to stem ratio, and growth ratios were calculated. With these results, for the growth variables, regression curves were estimated as a function of the rest days offered by each treatment. Despite the lower mass of forage obtained when the leaf area is severely defoliated, the species presents even accumulation of biomass and foliar area. Severe grazing intensity resulted in greater accumulation of leaves, reflected in the leaf area ratio and leaf weight ratio. The lenient intensities provide less rest time between grazing, requiring a greater number of paddocks. Under the research conditions, severe defoliation provides less forage to the animals.

Direct and maternal breed additive and heterosis effects on growth traits of beef cattle raised in southern Brazil.

The objective of this study was to compare growth from birth to slaughter of different breed groups that were raised in Rio Grande do Sul, Brazil and estimate the consequent breed additive and heterosis effects. Caracu (C), Hereford (H), and Nelore (N) sires were mated with Angus (A) dams, and A sires were mated with H and N dams to produce a first generation of crossbred progeny that was contemporary with purebred A, H, and N calves. Heifers from this first generation (G1) were mated with Brangus (BN) and Braford (BO) sires to produce a second generation (G2) of progeny. Data were analyzed to estimate breed group means, individual and maternal breed additive effects, and heterosis effects on birth weight, weaning weight, preweaning average daily gain, yearling weight, postweaning average daily gain, fattening phase initial weight (around 19 mo), final weight (around 24 mo), average daily gain in the fattening phase, and age at slaughter. In general, crossbred calves outperformed purebred calves. Angus-N and CA crossbred cows weaned heavier calves. Individual taurine-indicine heterosis (Z) significantly increased weaning weight. The AN, NA, and CA steers were heaviest at yearling, whereas NA, CA, AN, and HA had the greatest final weights. However, AH steers were 1 mo older at slaughter than NA contemporaries. Taurine breed effects on postweaning traits and final weight were greater than for N. Maternal breed effects on birth weight and average daily gain in the fattening phase were greater for A and H than for N. In conclusion, heterosis effects were sufficiently large for use of N to be recommended as a component of such systems, despite their relatively low-breed additive effects compared with taurine breeds. Moreover, germplasm from the tropically adapted Bos taurus C may be particularly useful when increased milk production is desired. With the breed and heterosis effects derived in the present study, it is possible to predict the performance and infer which breed and breed crosses will perform better in crossbreeding systems designed for the subtropical conditions of southern Brazil and similar regions.

Productive efficiency of cows primiparous aberdeen angus of the body size and milk production levels / Eficiência produtiva de vacas primíparas aberdeen angus de diferentes tamanhos corporais e níveis de produção de leite

Assessment of the productive efficiency of 30 primiparous Aberdeen Angus cows of different body sizes, classified at calving as heavy (375±10.5 kg) or light (283±7.7 kg), and different total milk-yield levels, classified as high (868±24.5 kg) or low (547±18.3 kg). Heavy cows were superior in weight at calving and weaning, but there were no differences in milk yield and weight at birth and weaning of calves. Heavy cows were less efficient than light cows in the production of kilograms of calves per 100 kg of cows at calving and at weaning. High milk producing cows were heavier at calving and had heavier calves at birth and weaning, but did not differ between the milk-yield levels for the variation in daily weight. The variation in daily weight of the calves was greater from high-producing cows. High milk producing dairy beef cows were more efficient at weaning, and their calves required less milk to produce one kilogram of live weight.

Objetivou-se avaliar a eficiência produtiva de 30 vacas primíparas Aberdeen Angus, de diferentes tamanhos corporais, classificadas ao parto em pesadas (375±10,5 kg) ou leves (283±7,7 kg) e diferentes produções totais de leite, classificadas em alta (868±24,5 kg) ou baixa produção (537±18,3 kg). Vacas pesadas foram superiores no peso ao parto e ao desmame sem diferença na produção de leite e no peso ao nascimento e desmame dos bezerros. Vacas pesadas foram menos eficientes na produção de quilograma de bezerros por 100 kg de vacas ao parto e ao desmame. Vacas de alta produção de leite foram mais pesadas ao parto, bem como produziram bezerros mais pesados ao nascer e ao desmame, porém não diferiram entre os níveis de produção de leite na variação diária de peso. A variação diária de peso dos bezerros foi superior nos filhos de vacas de altas produções de leite. Vacas de alta produção de leite foram mais eficientes ao desmame e seus bezerros necessitaram de menor quantidade de leite para produzir um quilo de peso vivo.

Performance of beef cows of different genetic groups in natural and cultivated pastures / Pastagens naturais e cultivadas no desempenho de vacas de corte de diferentes grupos genéticos

The objective was to assess the performance of 96 pregnant cows of the genetic groups (GG) Charolais (C), Nellore (N), ½ CN and ½ NC, subjected to the following treatments: kept exclusively in natural pastures (NP) throughout the experimental period; kept in cultivated pastures (CP) from July 15 to Setp 15 (CPNP) or from Sept 15 to Nov 15 (NPCP) and the remainder of the experimental period in NP. The weight at the end of the first grazing period (Sept 15) was higher for the CPNP cows than those of the NPCP and NP. The weight at the end of the second period (Nov 15) was 456, 428 and 392 kg respectively for NPCP, CPNP and NP. At calving, the heaviest cows were the CPNP, followed by the NPCP and the NP. At weaning, 90 days postpartum, the heaviest were the NPCP, followed by the CPNP and NP. Nelore cows were less heavy in all evaluations, followed by C, with the F1s' weight higher than the purebreds. The grazing sequences did not affect the percentages of the cows in estrus and pregnancy, but did influence the invervals between calving and first estrus postpartum (ICE). The GG influenced the rate of cows in estrus, pregnant and the ICE which was lower in the F1 (103 days), followed by the C (109 days) and had the largest interval N (119 days). The grazing sequences affect the average daily weight gain (ADG) of calves until weaning at 90 days of age. The GG of the calf affected the ADG at to 210 days.

Objetivou-se determinar o desempenho de 96 vacas prenhas dos grupos genéticos (GG) Charolês (C), Nelore (N), ½ CN e ½ NC, submetidos aos seguintes tratamentos: mantidas exclusivamente em pastagens naturais (PN) durante todo o período experimental; mantidas em pastagens cultivadas (PC) a partir de 15 de julho a 15 de setembro (PCPN) ou a partir de 15 de setembro a 15 de novembro (PNPC) e o restante do período experimental em PN. O peso no final do primeiro período de pastejo (15 de setembro) foi maior para as vacas PCPN que as do PNPC e PN. O peso no final do segundo período (15 de novembro) foi de 456, 428 e 392 kg, respectivamente, para PNPC, PCPN e PN. No parto as vacas da PCPN foram mais pesadas, seguidas pela PNPC e a PN. Ao desmame 90 dias de pós-parto o grupo mais pesado era de vacas da PNPC, seguido pelo PCPN e PN. Vacas N foram menos pesadas em todas as avaliações, seguidas pelas C, com o peso dos F1s maior do que os puros. As seqüências de pastagem não afetaram os percentuais de vacas em cio e prenhes, mas influenciou os intervalos entre partos e pós-parto ao primeiro cio (IPC). O GG influenciou a taxa de vacas em estro, prenhes e IPC que foi menor nas F1 (103 dias), seguidas das C (109 dias) e as N tiveram o maior intervalo (119 dias). As sequencias de pastejo influenciaram o ganho de peso médio diário (GMD) de bezerros até a idade do desmame aos 90 dias de idade. O GG do bezerro afetou a GMD até os 210 dias.

Análise de eficiência econômica de sistemas de cria com diferentes idades de desmame dos bezerros / Analysis of economic efficiency of breeding systems with different weaning ages of calves

O presente estudo objetivou avaliar o retorno econômico em rebanhos de cria submetidas ou não ao desmame precoce (DP), por três anos consecutivos. Através de resultados experimentais de desempenhos de rodeios de cria, simulou-se duas estruturas de rebanhos com diferentes idades de desmame para sistemas produtivos em áreas de 2000 hectares. A avaliação econômica foi realizada através das receitas dos sistemas com números, pesos e valores das categorias, subtraindo-se as despesas adicionais do desmame precoce. Foram considerados nos custos do DP os gastos adicionais com alimentação e manejo sanitário dos bezerros. As taxas de desmame foram de 83,6% para o (DP) e de 44,5% para desmame a idade convencional (DC). Os sistemas originaram a produção de 139.306 e 90.578 kg de bezerros para sistemas DP e DC, respectivamente. O sistema DP foi mais eficiente, produzindo lucro total de 19.361 kg de bezerros, com retorno de R$ 5,76 para cada R$ 1,00 investido. A soma das produções em kg de pesos das categorias de vacas, bezerros (as) foram de 103.848 e 65.115 kg para DP e DC, respectivamente. O aumento na taxa de prenhez aumentou a taxa de desfrute com 39,12 e 25,04 % respectivamente para DP e DC. Apesar dos gastos adicionais ao sistema produtivo, a utilização do DP permitiu maiores ganhos de pesos, melhor valorização no preço de vendas das vacas de descarte vendidas gordas para abate, viabilizando a sua utilização pelo superávit das receitas em relação às despesas comparado ao DC. O desmame precoce proporciona diluição dos custos e uma maior eficiência produtiva das vacas.

This study aimed to evaluate the economic returns of beef cow herd subject or not to early weaning (EW), during three consecutive years. Using experimental results of the performance of beef cows, two structures of cow herds were simulated with different weaning ages of production systems in areas of 2,000 hectares. The economic evaluation was performed by the revenue of the systems with numbers, weights and values of the categories, subtracting the additional costs of EW. We considered in the costs of EW the additional spending on food and sanitary handling of calves. Weaning rates were 83.6% for EW and 44.5% for weaning at conventional age (CW). The systems originated the production of 139,306 and 90,578 kg of calves for the EW and CW systems, respectively. The EW system was more efficient, producing total profit of 19,361 kg of calves, with a return of R$ 5.76 for each R$ 1.00 invested. The sum of the productions of weights of cows and calves were 103,848 and 65,115 kg for EW and CW, respectively. The increase in pregnancy rate increased the offtake rate with averages of 39.12 and 25.04%, respectively, for EW and CW. Despite the additional costs to the productive system, the use of EW showed the highest weight gain, best value in the sales price of cull cows sold fat for slaughter, enabling its use by the surplus of revenue over expenses compared to CW. Early weaning provides dilution of costs and greater production efficiency of cows.