Physiological parameters, hair coat morphological characteristics and temperature gradients in holstein-gyr crossbred cows / Parâmetros fisiológicos, características morfológicas do pelame e gradientes térmicos de vacas cruzadas holandês-gir

The aim of this study was to assess physiological parameters, hair coat morphological characteristics and temperature gradients in crossbred Holstein-Gyr cows in the municipality of Tapira, Minas Gerais (MG), Brazil. Forty-nine lactating cows from six Holstein (H) and Gyr (G) genetic groups (1/4H 3/4G, 3/8H 5/8G, 1/2H 1/2G, 5/8H 3/8G, 3/4H 1/4G and 7/8H 1/8G) were distributed in a completely randomized design. The dry-bulb temperature and relative humidity were recorded, and the temperature and humidity index (THI) was calculated. The rectal temperature, respiratory rate and body surface temperature were measured, as were hair thickness, numbers, length and angle. Cows with a greater than 50% Holstein breed ratio (5/8H 3/8G, 3/4H 1/4G and 7/8H 1/8G) showed a higher respiratory rate and greater hair length than animals with genetic composition equal to or greater than 50% Zebu (1/2H 1/2G, 3/8H 5/8G and 1/4H 3/4G). Animals from the 1/2 and 1/4 HG genetic groups showed the greatest hair angle (P<0.05). With respect to climatic characteristics, the examined locality was within the thermoneutral zone and therefore did not impose conditions of thermal stress. The animals exhibited thermoregulation and hair coat characteristics that were within physiological parameters.

Objetivou-se avaliar parâmetros fisiológicos, características morfológicas de pelame e gradientes térmicos de vacas cruzadas Holandês-Gir no município de Tapira, MG. Foram utilizadas 49 vacas em lactação de seis grupos genéticos Holandês (H) e Gir (G): 1/4H 3/4G, 3/8H 5/8G, 1/2H 1/2G, 5/8H 3/8G, 3/4H 1/4G e 7/8H 1/8G distribuídas em delineamento inteiramente ao acaso. A temperatura de bulbo seco e umidade relativa foram registradas e calculou-se o índice de temperatura e umidade (ITU). A temperatura retal, frequência respiratória, temperatura da superfície corporal, espessura, número, comprimento e inclinação dos pelos foram mensurados. Vacas com proporção maior que 50% da raça Holandesa (5/8H 3/8G, 3/4H 1/4G e 7/8H 1/8G) apresentaram frequência respiratória e comprimento dos pelos maiores em comparação aos animais com composição genética igual ou superior a 50% do Zebu (1/2H 1/2G, 3/8H 5/8G e 1/4H 3/4G). Os animais do grupo genético 1/2 e 1/4 HG apresentaram a maior inclinação de pelo (P<0,05). As características climáticas da localidade estiveram dentro da zona de termoneutralidade, não impondo desta forma condições de estresse térmico e os animais apresentaram características de termorregulação e de pelame dentro dos parâmetros fisiológicos.

Características termorreguladoras no início da gestação e índices reprodutivos de matrizes suínas de diferentes ordens de parto / Thermoregulatory characteristics in early pregnancy and reproductive efficiency of sows of different parity orders

Neste estudo objetivou-se avaliar algumas características termorreguladoras no início da gestação, bem como obter alguns índices reprodutivos de matrizes suínas de diferentes ordens de parto. Matrizes de 0 a 11ª ordem de parto (98) foram divididas em nulíparas, primíparas, de segundo ao sexto parto e do sétimo ao décimo primeiro para quantificar a frequência respiratória, temperatura retal e temperatura da pele em três momentos da gestação: no dia da primeira inseminação artificial, do segundo ao quarto dia de gestação e do décimo ao décimo terceiro dia. Também calcularam-se os gradientes térmicos entre temperaturas retal e da pele (TR-TP), temperaturas retal e do ar (TR-TA) e temperaturas da pele e do ar (TP-TA). Outras 164 matrizes de 1ª a 12ª ordens de parto: primíparas, de segundo parto, do terceiro ao sétimo e do oitavo ao décimo segundo parto foram utilizadas para obter o período de gestação e número de leitões nascidos vivos. Os diferentes momentos da gestação e ordem de parto não influenciaram as médias da frequência respiratória e da temperatura da pele. Matrizes de 7ª a 11ª ordem de parto apresentaram menor média de temperatura retal que as demais ordens. Em relação aos momentos da gestação, foi observada menor temperatura retal do segundo ao quarto dia de gestação comparado ao dia da primeira inseminação e do décimo ao décimo terceiro dia de gestação. O gradiente TR-TP de leitoas foi maior em comparação às demais ordens de parto. Matrizes de 7ª a 11ª ordem de parto apresentaram valores dos gradientes TR-TA e TP-TA maiores em relação às demais ordens de parto. O gradiente TR-TP aumentou conforme se distanciou do dia da inseminação artificial e os gradientes TR-TA e TP-TA, diminuíram. Matrizes de 8ª a 12ª ordem de parto apresentaram maior período de gestação (114,87±1,55 dias) comparada aos demais grupos de ordem de parto (113,28±1,43 para primíparas; 113,09±1,77 para 2º parto e 113,83±1,33 dias para 3º ao 7º). O número de leitões nascidos vivos não diferiu entre as diferentes ordens de parto. Momentos da gestação até o 13º dia e a ordem de parto não influenciam a temperatura da pele medida pela manhã e a frequência respiratória avaliada às 14 horas. Entretanto, matrizes suínas mais velhas (7ª a 11ª ordem de parto) apresentam menor temperatura retal pela manhã e maior período de gestação. A ordem de parto não interfere no número de nascidos vivos na linhagem comercial PenArlan.

The aim of this study was to evaluate some of the thermoregulation characteristics during early pregnancy, and obtain reproductive parameters of sows of different birth orders. Sows 0-11 the parity orders (98) were divided into groups consisting of nulliparous; primiparous; sows from the second to sixth; and sows from the seventh to eleventh birth, in order to quantify the respiratory rate, rectal temperature and skin temperature at three time intervals of pregnancy: the day of first artificial insemination, the second to the fourth day of gestation and the tenth to the thirteenth day. The thermal gradients between rectal and skin temperatures (RT-ST), rectal temperatures and air (RT-AT) and skin temperatures and air (ST-AT) were also calculated. Another 164 sows from 1st to 12th parity orders were grouped as follows: primiparous, second parity, the third to the seventh, and the eighth to twelfth parity orders were used to obtain data on gestation period and number of piglets born alive. The different stages of gestation and parity orders did not influence the average respiratory rate and skin temperature. Sows of 7th to 11th parity orders showed lower mean rectal temperature than the other orders. As regards gestation times, lower rectal temperature was observed on second to fourth day of gestation compared with the first day of insemination and the tenth to the thirteenth day of gestation. The RT-ST gradient of gilts was higher compared with that of other parity orders. Sows of groups from 7th to 11th parity orders showed higher values of gradients RT-AT and ST-AT compared with other parity orders. The RT-ST gradient increased as time passed after the day of insemination, and RT-AT and ST-AT gradients decreased. Sows from 8th to 12th parity orders showed longer gestation period (114.87 ± 1.55 days) compared with the other groups of parity order (113.28 ± 1.43 for primiparous; 113.09 ± 1.77 to 2nd parity orders and 113.83 ± 1.33 days for the group from 3rd to 7th parity orders. The number of piglets born alive did not differ between the different parity orders. Time intervals of pregnancy until the 13th day and the parity orders did not influence the skin temperature measured in the morning, and respiratory rate measured at 14 hours. However, older sows (7th to 11th parity order) had a lower rectal temperature in the morning and longer gestation period. The parity order did not interfere in the number of live births in the commercial line PenArlan.

Níveis de hormônios tireoideanos circulantes, desempenho e qualidade de carcaça e carne de suínos em crescimento e terminação / Levels of circulating thyroid hormones, performance and carcass and meat quality of growing-finishing swine

Objetivou-se neste estudo comparar as concentrações séricas de triiodotironina (T3) e tiroxina (T4) em suínos de linhagem comercial no início e término da fase de crescimento-terminação, correlacionando-os com o desempenho produtivo, características de qualidade de carcaça e da carne. As amostras sanguíneas de 48 animais foram coletadas no início e no final da fase de crescimento-terminação por punção da veia jugular externa, sempre no mesmo horário (8-10h). As determinações séricas dos hormônios tireoideanos foram feitas por enzimaimunoensaio. Foram feitas avaliações de desempenho e de qualidade de carcaça e de carne. No início e final do alojamento, as concentrações séricas de T3 foram de 1,85 e 1,32nmol L-1, respectivamente, e para T4 de 100,33 e 86,53nmol L-1, respectivamente. Houve correlação negativa e baixa entre T3 final e ganho de peso médio diário, peso final e espessura de toucinho. T4 inicial correlacionou-se negativamente e moderadamente com peso inicial. Os valores de T3 e de T4 em suínos no início da fase de crescimento-terminação são maiores que na terminação. Os hormônios tireoideanos estão associados com o peso inicial e final, espessura de toucinho na última lombar, pH45min e pH24h de suínos em crescimento-terminação.

The objective of this study was to compare serum concentrations of the hormones triiodothyronine (T3) and thyroxine (T4) in pigs on commercial line beginning and end of growing-finishing phase, correlating them with productive performance and quality characteristics of carcass and meat. Blood samples were collected from 48 animals at the beginning and end of growing-finishing phase by puncturing the jugular vein, around the same time (08:00 to 10:00a.m.). Measurements of serum thyroid hormones were made by enzyme-immunoassay. It was evaluated the performance and quality of carcass and meat. At the beginning and end of the housing, serum T3 concentrations were 1.85 and 1.32nmol L-1, respectively, and T4 of 100.33 and 86.53nmol L-1, respectively. There was negative correlation between T3 and low-end and average daily weight gain, final weight and backfat thickness. Inicial T4 was moderately and moderately negatively correlated with initial weight. The values of T3 and T4 in pigs early in the growing-finishing phase are larger than in termination. The thyroid hormones are associated with the initial and final weight, backfat thickness at the last lumbar, pH45min and pH24h of growing-finishing pigs.

Association of the estrogen receptor gene Pvu II restriction polymorphism with expected progeny differences for reproductive and performance traits in swine herds in Brazil

Estrogen has an important function in swine reproduction and growth. A Pvu II restriction enzyme polymorphism has been proven to be an important genetic variation in the estrogen receptor gene (ESR) and may be considered as a candidate gene for use in pig production but there is no data regarding the prevalence of this polymorphism in the Brazilian pig population. We used DNA samples from the following three purebred pig breeds: Large White (336 females and 26 males), Landrace (304 females and 27 males) and Pietrain (125 females and 11 males). The ESR genotyping was performed using PCR-RFLP. For each breed, genotypes for the ESR gene were compared independently for expected progeny differences (EPD) in litter size (LS), average daily weight gain (DWG) (g/day) and back fat thickness (BT) as measured in mm by ultrasound. In the Large White breed, but not the other breeds, the ESR genotype was significantly (p < 0.05) associated to LS, DWG and BT. Large Whites genotyped as AA or AB had higher EPD values for the LS and BT traits compared to BB Large Whites, while AA Large Whites had higher DWG EPD values than BB Large Whites. Our results for the Large White population showed that the A allele has a beneficial effect on LS, DWG and BT expected progeny differences.

Association of a PIT1 gene polymorphism with growth hormone mRNA levels in pig pituitary glands

Fourty-six non-castrated, halothane-free, male Landrace pigs were genotyped by PCR-RFLP for the Rsa I polymorphism in the PIT1 gene and classified into AA and AB genotypes. Total RNA was extracted from the pituitaries and the relative quantities of growth hormone (GH) mRNA were determined by semi-quantitative RT-PCR. Pigs with the AB genotype had higher levels of GH mRNA than those with the AA genotype (p = 0.034; Kruskal-Wallis test). This result suggests that the Rsa I polymorphism may be involved in Pit-1 protein expression or function, which in turn may influence GH transcription and expression. Thus, the Rsa I PIT1 gene polymorphism in this pig line may be used as a molecular marker to identify higher GH expression and possibly select for carcass and performance traits affected by GH.

Protocol for extraction of genomic DNA from swine solid tissues

Molecular diagnostics are performed by using DNA from different body tissues. However, it is necessary to obtain genomic DNA of good quality. Due to the impossibility of collecting blood from slaughtered animals, DNA extraction from solid tissues is necessary. The objective of this study was to describe a protocol of DNA extraction from swine skin, adipose, brain, liver, kidney and muscle tissues. We obtained high molecular weight DNA of good quality, shown by agarose gel and amplification of two DNA fragments, 605bp and 891pb, by PCR. Spectrophotometric analysis of DNA concentration showed variation among the DNA from different tissues, with the liver and adipose tissues presenting the greatest and the smallest concentration, respectively. The described protocol has proven to be advantageous due to its simplicity, quickness, affordable reagents and absence of phenol, resulting in a high molecular weight DNA of good quality from several tissues