1161
Body weight adjustments for feeding status and pregnant or non-pregnant condition in beef cows*
Body weight adjustments for feeding status and pregnant or non-pregnant condition in beef cows*
Tuesday, July 22, 2014
Exhibit Hall AB (Kansas City Convention Center)
Abstract Text: Dataset from 49 multiparous Nellore cows (32 pregnant and 17 non-pregnant) averaging 451±10 kg was used to develop a set of equations and relations for body weight (BW) adjustments in pregnant or not pregnant cows. Cows were fed a corn silage based diet and weighed every 28 days (0700 h, before feeding) to obtain BW, and reweighed at the same time following day after 16 h fasting to obtain shrunk body weight (SBW). Pregnant cows were separated into four groups of 8 cows and harvested at 136, 189, 239 and 269 days of pregnancy (DOP) to obtain the empty body weight (EBW) and the weight of components related to pregnancy. A set of linear and non-linear equations was tested, based on theoretical suppositions, to establish the relationships between the BW, SBW and EBW of pregnant and non-pregnant cows as function of DOP. The pregnant compound (PREG) was defined as the weight genuinely related to pregnancy, that includes the gravid uterus minus the non-pregnant uterus plus the accretion in udder related to pregnancy. The PREG was deducted from the SBW or EBW of a pregnant cow to estimate the non-pregnant weights (SBWnp and EBWnp). Results are shown in Table 1. There was no accretion in udder weight up to 238 days of pregnancy. We conclude that the weight related to the pregnancy can be estimated in a live cow allowing estimate non-pregnant EBW and SBW of a pregnant cow and calculates the body gain of only maternal tissues.
*Funded by INCT-CA, CNPq, FAPEMIG.
Keywords: Bos indicus, gestation, gravid uterus
| Estimated variable | Predictors | Relation |
| Non-pregnant cows | ||
| SBWnp | BW | SBW=0.8084×BW1.0303 |
| EBWnp | SBWnp | EBWnp=0.8424×SBWnp1.0122 |
| Pregnant cows | ||
| SBW | BW | SBW=0.8084×BW1.0303 |
| SBWnp | SBW and PREG | SBWnp=SBW–PREG |
| PREG | If DOP≤238: GUdp If DOP>238: GUdp and UDdp |
If DOP≤238: PREG=GUdp If DOP>238: PREG=GUdp + UDdp |
| Gravid uterus accretion due to pregnancy (GUdp) | GU and UTnp | GUdp = GU–UTnp |
| Gravid uterus (GU) | DOP or DOP and body condition score (BCS) | GU = 0.2243×BCS0.3225×e((0.02544–0.0000286×DOP)×DOP), or GU = 0.2106×e((0.03119–0.00004117×DOP)×DOP) |
| Non-pregnant uterus (UTnp) | SBWp and GU | If DOP≤238: UTnp=0.0012×(SBW–GU+0.6) If DOP >238: UTnp=0.0012×(SBW–GU+0.6–2) |
| Udder accretion due to pregnancy (UDdp) | UDnp and DOP | UDdp=UDnp×e((DOP–238)×0.0109)–UDnp |
| Non-pregnant udder (UDnp) | SBWp and BCS | UDnp=SBWnp×0.00589×BCS0.2043, or If DOP≤238: UDnp=(SBW–GUdp)×0.00589×BCS0.2043 If DOP >238: UDnp=(SBW–GUdp–2)×0.00589×BCS0.2043 |
| EBW | EBWnp and PREG | EBW=EBWnp+PREG |
| EBWnp | SBWnp | EBWnp=0.8424×SBWnp1.0122 |